The 1949 Sylvania 1-076 console arrived today! Three hours late. The poor drivers hit freezing rain and had to drive 45 mph. The driver looked pretty tired.

I'm very grateful to the seller for finding this set and keeping it safe over the years. I'm sure he was attached to it. I'm glad he found me when he realized that he needed to part with it. I'm also glad that he was still willing to sell to me after our initial missed connection for transport.

I've attached photos. The finish isn't bad considering it's age. Except for the top. That's pretty worn and starting to peel. The fabric is missing from the bottom right door that should match the speaker cloth. The wood though matches the rest of the set. Whoever finished it, matched the color well. I think I'll need to refinish the top, but cleaning and restoring the rest of the finish will probably be sufficient.

The speaker will need some work. ;)

The record changer is missing. I've obtained a V-M 951 to replace it with. It should use a V-M 406 though. They look similar and the 951 is probably a much better unit, but if anyone has a lead on a 406 please let me know.

The Horizontal Discriminator Transformer has a bad ding on top. I doubt that it hurt anything though. It looks like something was trying to get out of the end of the doghouse. Some serviceman may have dropped bolts or something into it while working on the set.

The last time I saw this model chassis was when I was very young. It seemed huge back then. Now it seems tiny. I like how neatly it's laid out.

The CRT bezel has some crazing, but not bad. The CRT looks good. I'll have to test it. It's irreplaceable with the same type. I'd have to do a small modification to use any other CRT. I'm crossing my fingers.

I'll have to leave the cabinet in the garage for now, but I'll bring the chassis in this week and maybe get some photos of the bottom. Then news will slow down because I'll be taking my time checking it out and making sure it matches the rev C15 chassis that it is.

John

Nice set John!

The chassis is very interesting looking, I don't think I've ever seen a Sylvania of that vintage before.

Great news! I'd be hugging that Sylvania after all the trouble you went to get it! I better get my act together and search for that missing alignment data...

Hi John;
Congratulations on the new addition. What a great achievement to finally make it happen after all this time and grief!!

That's one really nice looking combo unit, and I'm guessing quite rare too. I don't think I've ever seen an early Sylvania set like that.

I can't wait to see it after you've completed the restoration.

Good luck with it and keep us posted on your progress.

Bob.

I too have never seen a Sylvania that old. Very interesting set. Looking forward to seeing more pics of that chassis. Good luck and I'm glad you finally got it home safe!

Unique layout,, nice set and I love it.
Dan

I removed the speaker and chassis from the cabinet today. While working near the speaker I noticed a very cold Black Widow Spider. It was moving quite slowly in the sub 20 temp.

Here are some photos.

It's pretty dirty. Besides the dust it has a yellow haze over everything. Perhaps tobacco tar.

The photo on the far right shows the RF HV section. That section has a black beauty in it. In the center photo you can see the components on the bridge.

The only work that I can find that anyone did is replacing the soldered in fuses.

I'm a little worried about the transformer. Some tar has dripped out. But the whole set seems to have gotten quite warm. All the ceramic disk caps have bubbled wax. It probably got pretty toasty on a warm night in Georgia.

There is a large white power resistor that was too close to the chassis and appears to have been arcing to it.

Most of the paper and electrolytic caps are reasonably accessible. There are a few that will be difficult.

I'm going to have to learn how to restring a dial cord also.

John

It looks like that sweep chassis, HV box and all, can be unplugged and removed. Might wanna look into that...

It looks like that sweep chassis, HV box and all, can be unplugged and removed. Might wanna look into that...

That's correct. There one big plug. There's also one separate wire that looks like a mini twin lead. I'm not sure if I want to remove the bridge during the restoration or not.

John

I'd pull it out, it's gonna be a LOT easier to fix the caps and all, plus you'll want to take the CRT out, clean it well, plus the HV box too. And inspect the HV lines.

Believe me, it's easier to work on a set when you're not trying to solder around a CRT and all. If it breaks into modules, take advantage of that feature!

I'd pull it out, it's gonna be a LOT easier to fix the caps and all, plus you'll want to take the CRT out, clean it well, plus the HV box too. And inspect the HV lines.

Believe me, it's easier to work on a set when you're not trying to solder around a CRT and all. If it breaks into modules, take advantage of that feature!

I guess I'll do it then. I admit I'm pretty nervous about the CRT. It'll probably be safer if I remove it. And if I remove it it'll make the dial cord replacement a snap too.

John

Small crts like that aren't bad. Just make sure you got a place for it first - get some old towels and make a 'bed' in a safe place for it. Remove the plug in the back and focus/and deflection coils, then loosen the support strap up front (hold the tube so it doesn't fall out), and carefully lift the band out of the way and slide the tube out the front. Just don't bang it into things or drop it, and don't hold it by the neck.

I much prefer working on a chassis without the tube in it.

Oh yeah, ground the hole where the HV lead plugs in, even if the set's been off a while. Some tubes like to store up a surprise over time anyway (not dangerous, but could startle you into dropping the tube).

Once the tube's safely out, I like to clean it nicely, to get all that dust and junk off. Just don't removbe the dag coating :)

I checked the tubes. Out of 32 tubes only the 6T8 was bad.

I had to repair a Sencore SuperMack CR41A before I could try to test the 10MP4. I tried it out on a 5AXP4 and 10BP4 that I had tested previously and it worked well.

When I tried it on the Supermack the filament lit up but I couldn't set the balance or read any emission. Small wonder. The CR41A measures emission through G2. There is no G2 in a triode. They must have made a mistake when they listed the 10MP4 in the settings booklet.

I'll have to make up some flying leads for the B&K to test it. I'll only be able to test the emission though.

The CRT base was loose so I was focusing on it while removing the socket. I didn't notice that I had a finger pressed against one lead and the solder tab broke off of the pin socket. I can solder it back onto the pin socket, but it might be nice to replace the socket.

Can anyone tell me where to look for a CRT socket? It would be the same as used on a 12LP4.

John

The socket's a 12 pin? They're common as dirt - someone with a parting out set should have one.

Look for an old picture tube brightener...a cheap and easy donor.

Look for an old picture tube brightener...a cheap and easy donor.

I should have thought of that! Thanks!

John

Apparently triode CRTs are about as testable as electrostatic CRTs. None of the CRT analyzers that I'm aware of can test them.

I wanted to know the health of the 10MP4 in the Sylvania. I decided to measure the emission by using G1.

At least now I know that the CRT isn't dead. I measured a very high emission, but doing it this way collects most all of the electrons emitted from the cathode rather than the ones that go through the grid. The portion of the cathode that they would originate from could still be weak. You can read about why here http://www.sencore.com/uploads/files/RejuveCRTs.pdf

The Sylvania Technical Manual says that the G1 cutoff is measured by observing the extinction of the focused beam on the screen.

I plan on doing this. I'll need to supply the HV and also be very careful to start with G1 above the cutoff so as not to burn a hole in the screen. If it passes this test then it should be in pretty good shape.

Of course I could just test it in the chassis once I finish cleaning, recapping, and checking all of the resistors. But this is going to take a while and I'd like to know soon whether I need to get it rebuilt or not.

John

I did say I would be slow. Since I couldn't get the CRT loose from the front mount I removed the front plate. That actually was helpful because There is a fiber disk between the focalizer and the yoke. It is tight on the neck of the tube and the tabs caught on the base. That wouldn't have been a problem except that the base is loose so I wanted to be gentle. The front plate helped me keep the CRT aligned while I manipulated the disk.

Now I can remove the bridge and have easy access to clean the chassis as nasadowsk suggested.

John

John,
I may have a VM 406 for you. Let me look and if i still have it, i'll let you know.
-Tony

That would be great!
John

I dismounted the bridge and started cleaning it and the chassis. So far no surprises other than a paper cap that has leaked a fair amount of oil

I managed to finaly remove the front plate from the CRT. The rubber pads were glued to it and the support plate. The pads peeled from the glue, but the glue is still on the CRT. I'm going to leave it because it won't be visible and it's too difficult to get off. It's a contact type cement.

There's a long concentric shaft on the tuner. The outper part changes bands and the center tunes. There was oil between them and it has gotten to be very viscous. I don't want to dissassemble it if I don't have to.

I might try the CRC electronic cleaner.

John

Someone who worked on this set previously moved C133 from the bridge down to the main chassis. It connects to pin 6 on the the 6AU6 horizontal control. They took a piece of twin lead and spit it in two and ran that from C133 back up to pin 6.

I can't understand why they did that. It looks like the original electrolytic since it has a Sylvania part number on it. I'm inclined to move it back to the bridge unless someone can come up with a theory as to why it's better in the chassis. The long run to pin 6 seems strange.

The schematic and layout can be found at:

https://www.msu.edu/~yurkon/Sylvania_9-2_Sup2.pdf

John

Very Kool tv looking forward to seeing the pics. of it finished.
Good Luck Damen

I'm still making slow progress. Many of the paper caps are difficult to get to, buried under other parts. I found one good paper cap so far. It was the only one that didn't have blisters on the outside. I wonder if that's related.

I've also found quite a few open or out of tolerance resistors in the audio output section.

I started to do a quick check by checking the tube chart resistances given by the SAM's. I quickly learned that this was a waste of time. Many of the resistances given are wrong. The schematic from the same SAM's folder seems to agree with what I measure. It'll be easer just to check the individual resistors and not worry about whether the SAM's got it right.

John

I've replaced all the paper caps and some of the electrolytics. I'm sure I'll get some flak for it but I kept the electrolytics that had better ESR than the replacements and had leakage in the acceptable range.

I cleaned the chassis. It's not as new looking as many of you guys are capable of producing, but if you look at the photos in the early thread, it's an improvement. The dark area around the electrolytics on top is wax that had dripped from the horizontal output choke on the bridge. If I end up rebuilding those electrolytics I'll clean it up then.

I may paint the top of the power transformer, but I'm waiting until I see if I have to apply a hum fix to the transformer. They have you remove the top instead of removing the entire transformer to work on it.

The thing that took the longest was restringing the dial cord for the radio section. It has three idler wheels, drive pulley and capacitor pulley. Only the capacitor pulley is accessible, you have to use hooks to deal with the others all the while maintaining enough tension to keep the cord from falling off. I hope I never have to do that again.

Now I have to work on the bridge which has just as many paper caps.

John

I was hoping to finish up the set tonight. That was too optimistic. There was way too much wrong with the HV section and I need to get some parts.

Originally I claimed there was almost no work done on this set. That was clearly wrong. As I dug into it I found a mixture of high quality repairs and some pretty ham fisted stuff.

The ceramic disc I showed in another thread actually tested good. I replaced it anyhow. The bumble bees were all toast. A 100 ohm wire-wound was open. A 56K 2 Watt reads 100K. The factory manual shows it as 56K, the markings are for 56K, but the Sam's shows it as 5.6K. I bet that might have confused a few people.

I cleaned up the oil that leaked from the 10KV 0.005uF cap.

I removed the HV section from the bridge to make it easier to work on and minimize physical risk to the HV transformer.

There was an incredible cold solder joint on the lead that goes to the feedback winding on the HV transformer. It was just flopping around in the solder around it. I don't know how they managed that because the lead was well tinned. They had a ball of solder about the size of a pea.

I'll post some more photos once I finish the HV and before I install it back into the bridge.

John

I've finished recapping the Coffee Can HV and the bridge. Now I just need to reassemble everything and hope for the best.

The first photo is the back of the RF HV module. The long white capacitor is a 10KV 0.0005uF film cap.

The second photo shows the back of the bridge with the coffee can HV mounted back on to it. On the top between the yellow film capacitor and the black electrolytic there is what looks like a paper cap. That actually is a polystyrene capacitor and has unmeasurable leakage. I decided to leave it in since it didn't seem to be following the fate of the paper caps.

John

I was hoping to power the set up tomorrow. That won't happen now. While cleaning the controls I discovered that the Horizontal Center pot was bad. I opened it up hoping to repair it but it's beyond repair. It's a 140 ohm 2W wire-wound panel mount. 43-140CT by clarostat. The wire was blown in numerous spots. It must have seen a very high current to do that.

I think the closest I'm going to find is a 150 ohm 2 watt composition pot that I found at Newark. I'm going to go ahead and order that. If anyone should have something more appropriate they'd be willing to part with please let me know.

John

What about the selenium rectifiers?
They need replacing as well...
Bill Cahill

What about the selenium rectifiers?
They need replacing as well...
Bill Cahill

One of the dangers of posting progress; I was afraid someone would notice that. :o

The selenium rectifiers form a center-tapped full wave -125 VDC supply. There is a 39 ohm resistor in series with each rectifier. I believe they're there to limit in-rush current. They won't protect the transformer if the seleniums short.

The output of the supply is already fused. I intend to put a fuse in series with the 39 ohm resistors to protect the transformer.

On our original set we had to replace the seleniums once in its lifetime.

As long as the transformer is protected, I'm not worried. I have a lifetime supply of selenium rectifiers and if I have to change them every 5 years or so I don't have a problem with that. They're easy to get to and change.

I can't explain why I want to keep them in use anymore than I can explain why I want to watch a 60 year old TV. Maybe I just like the smell of garlic.

John

Well, I'm glad I went the variac route. I did use the watt-miser. I used it on the primary of the variac so I was only able to monitor total power and not the voltage and current separately.

Things were coming up nicely. While letting it sit at 90 VAC smoke suddenly wafting up. A 100 ohm plate resistor on the 4th video IF stage was overheating. Since I was watching the bottom of the chassis when this happened it took me a bit to understand what was going on. One end of the resistor goes to +170V and the other connects to the IF transformer primary which connects to the plate of a 6AG5. When I measured the IF transformer side of the resistor it showed zero ohms to ground. I thought the IF was shorted. I pulled the 6AG5 and immediately saw what the problem was. It had gone up to air.

The pins on this tube had been severely bent at some point in its life. It tested good so I kept it, but there must have been a small crack in the glass. As it heated up it eventually cracked open.

Up until this point everything was fine and the voltages were coming up properly and nothing was overheating. The power consumption was still below spec.

I'll start again tomorrow. It's late now.

John

I powered the TV up tonight. I checked out the FM receiver first and it sounds great! I need to make a loop antenna for the AM. It can't work without it. I tried anyway and all I heard was my neighbor's SSB transmission.

I then checked out the TV. I was surprised to get a raster let alone an image. I was very happy the the HV section was working because there were quite a few bad components that I had to replace.

I had to readjust the Horizontal frequency coil by about 15 turns to get it to get this close.

There is no audio on TV. But that's a pretty small section to look at so I don't expect it to be too difficult to fix.

Anyway, the image is below. All the major components are working so I should be able to fix the remaining problems.

Actually the main problem probably is that I wanted to try to keep the selenium rectifiers. They seem to test good, turning on at 6 volts and having zero reverse current at 100 volts. The low reverse current was pretty unusual.

They seemed fine until I plugged the HOT, VOT, and RF HV Osc tubes in. Then there was a 40 volt drop and the seleniums started to get warm. I was going to use NOS ones that I have, but they have a high reverse current.

As much as I like playing with old technology like selenium rectifiers, I'll have to give up on them.

Going to 1N4007's will bring the -90VDC up to -130VDC and may solve some of the apparent problems. That's not related to the sound though.

I may have to do a complete horizontal alignment since I replaced all the caps in that section.

I was very happy to see it do this much!

John

Looking good! Very good for the first power up. I've never had a terrible experience with seleniums; they just seem to be "weak" on some sets. (maybe most sets!) I agree, it is fun to get it working the "old way". I was thinking, you might just be the guy to try rebuilding a selenium!

Yes, it looks good. I can understand your desire to keep the selenium rectifiers. But, they will be a pain from this day forward. If you are looking for originality, you can hide a 1N4007 behind that selenium I am sure. Just a thought...

Looking good! Very good for the first power up. I've never had a terrible experience with seleniums; they just seem to be "weak" on some sets. (maybe most sets!) I agree, it is fun to get it working the "old way". I was thinking, you might just be the guy to try rebuilding a selenium!

Actually there are at least still two manufacturers of selenium rectifiers.

I might try putting together a supply with the NOS seleniums and a dummy load to see how they behave. I might have too high expectations for how I think they should test.

But, for now I'm going to use the 1N4007s. and an additional 110 ohms with each.

I'm glad I fused the seleniums in case they died.

John

Well, using the 1N4007s brought the -HV up. I was a little too conservative with the resistors. I'm about 5 volts low, but that shouldn't be a problem.

I saw no change in the performance. The AM radio is working to a degree now without the loop, but that's not related to the -HV since it doesn't use it. It's just that there's a strong AM station in the daytime.

I'm amazed that the set had a picture at all. While trying to figure out why the video was so weak and the AGC wasn't kicking in I discovered that the primary on the first video IF transformer is open. I only had a picture because of the signal bleeding through.

It's probably hopeless to ask, but does anyone have a Sylvania 125-0001 IF transformer? I don't think Merit made a replacement.

I may have to rewind it which would be difficult. It appears to be coated with glyptal which is extremely difficult to remove. On the other hand, the coil shows no signs of having been over heated. It might just be a cold solder joint to one of the terminations.

I suspect that once I get a decent signal through the video IF stages my horizontal problem will take care of itself.

Oh, the CRT HV is 500 volts low. I can only get it up to 9KV. I should be able to get 11KV max and set it to 9.5KV. I think it's because I have a weak 6Y6-G in there. The one in the audio section is better, but it doesn't fit under the coffee can. Which is funny, because it's the Sylvania tube. The weak 6Y6-G that fits is a Philco. I have a 6Y6-GT I can try. I didn't because Wallace's recommends using a coated 6Y6.

John

Here's a photo of the video IF transformer that I need to repair or replace.

John

I'm torn between rewinding the coil and repairing it. It has 16 turns and is bifilar wound. Should be easy enough to rewind, but just as easy to fix. Both ends are open. One end I can just reattach to the terminal, the other end I would need to splice.

I had to soak it in lacquer thinner. That didn't dissolve the alkyd coating but softened it enough to scrape off.

Any suggestions as to which route I should take?

There are only two components that could have caused the failure. Other than someone twisting the form while trying to adjust it.

One would be the tube which tested o.k. At least not shorted. The other is a 0.68 pF 500V axial ceramic. It's too small a value for me to test, but the leakage at 500V is less than 100 nA. There's a 0.005uF disc ceramic on the secondary that has 1.2uA leakage at 500V. That didn't cause any problems though. I'll replace it anyhow since it's really ugly looking.

The color code on the 0.68pF ceramic is Blue-Gray-Silver-Nothing. I'm not familiar with this coding. Anyone have a chart for this type of ceramic cap?

John

I decided to rewind the video IF transformer. You can see the progress below. It would have been easier if my eyes weren't the same age as the TV.

After installing it, it has a strong video signal. :banana: I have have a horizontal problem. I'll go through the horizontal alignment procedure and if that doesn't fix it I'll have to do some debugging. :scratch2:

I'll need to realign the video IF also. But, I need to do some work on my Hickok 610A first.

John

John,

Nice job on the IF transformer. Here is a link to capacitor color codes, hope it will help:
http://www.tpub.com/neets/book2/3g.htm

John,

Nice job on the IF transformer. Here is a link to capacitor color codes, hope it will help:
http://www.tpub.com/neets/book2/3g.htm

Thanks for the compliment and the link. The axial ceramic cap color code table is close. But, like all of the others I've looked at they don't include silver in the multiplier. I guess I should just assume it follows form since that gives the schematic value.

John

I think I've found the problem with the horizontal circuit. The symptom is that it's only stable with the blanking bar down the center of the screen.

I don't fully understand the circuit. It's a sine wave type horizontal AFC.

But suffice it to say that the output of the sync clipper is fed to the horizontal discriminator through a 100pF capacitor. It was supposed to be an axial ceramic. It's actually a Micamold.

All the bad things I've heard about micamolds are justified. If a capacitor can be evil, this one is. The discriminator circuit requires it to not have any leakage. It has about 16 uA at rated voltage. But it gets weirder. The capacitor testing gives up trying to measure the value if the cap's been resting for a long time. After measuring the leakage, the capacitance tests out at 300 pF. It then gradually ramps up to 3,000 pF after a few minutes of testing.

At least this one is easy to get to. The other one that I'll replace is used to turn the line cord into an FM antenna. Given that it would probably burn my house down I'm inclined to replace it.

I wish the 13 others weren't so difficult to get to; I'd love to replace them but since they seem to be working I guess I'll replace them when their time comes.

John

Finally! :banana:

I changed the micamold and found two caps I had switched. A 0.005 and a 0.010 uF. There's one micamold left that is for the horizontal ringing coil. It's hard to get to, but I should change it.

Here are some photos. Is this the typical linearity that you should expect for a set of this vintage?

John

John, those photos represent outstanding work on your part. Congratulations on getting that old babe back to as good as, or even better than, new.

As to linearity, looks to me like you're down to the point where any deviation may only be in the eye of the beholder.

Three cheers for a job well done! And thanks for sharing all the details with us.

Roger

Awesome!
-Tony

While doing some fine tuning of the set I realized that the Zenith Wavemagnet I picked up has the right inductance to use as a loop for the AM section of this set. I tried it without doing any alignment and the reception was amazing.

This might be pretty good for AM DXing.

John

I need some advice on dealing with a problem with the volume control on this set. It's a 1 meg composition pot tapped at 500K and 250K. It has a hollow shaft. The Photofact doesn't list any replacements other than Sylvania so it's pretty much going to be impossible to find.

The resistance from one end to the other is 1.2 Meg, which isn't so bad. The Symptom is that the volume jumps up to a loud leve when I start turning it up.

I've attached a scan of this section.

It seems that a spot was burned in the conductive film near the bottom of the pot. Possibly when paper cap C25 was leaky. As you go past this spot the resistance measured at the wiper jumps from 25 ohms to 250 ohms. If I measure the resistance to ground from the other taps they jump down to the correct value when the wiper is in the center of this spot. I imagine the conductive trace having a burned spot in the center of the trace, but good on both sides. I've attached a sketch of what I think it might look like.

I think the taps are there to keep the tone the same as the volume is changed. I could just short the 250K tap to ground. I'd lose a portion of the range. The tone might sound a little different. This would be the easiest solution.

I could try coating the spot with aquadag to cover the burned spot. If it's small enough, it might not be noticiable.

To get at it I have to remove the CRT, the front panel, and the plate that holds the pulley for the dial cord. I hope to avoid that.

Any other suggestions on how to attack this problem?

John

Well, the problem with the volume control wasn't what I thought it was, and the problem was fixed by an unfortunate accident.

Instead of a burned spot on the resistive trace, it was where the terminal on the ground side was riveted to the phenolic board with the resistive trace. I didn't notice that a tubular capacitor that is on the end of a coax running to the wiper of the volume control was too close to a resistor. It arced through the paint on the capacitor while I was watching and made violent discharges in the volume control. :yikes: I expected the worst. :worried: But, it turns out it just improved the connection so now the volume control tests and works perfectly! :banana:

John

While I was able to adjust the set to give a good picture, there was still a problem with the horizontal. I wasn't able to adjust it according to the service literature. Basically you're supposed to remove the discriminator tube, the 6AL5, adjust the frequency until the bar moves slowly across the screen and reinsert the tube. It should lock in at this point and then you adjust the phase.

They then have test the pull-in range by adjusting the frequency CCW until it unlocks, then adjust it back slowly until it locks in and you count the number of bars just before it locks in. Then CW and count the bars. They're supposed to be between 3-4 bars in both cases. In my case when I turned it one way it would just slowly drift across. In the other direction it wouldn't unlock until I made many turns.

I also wasn't able to adjust the phase independently.

I checked all the caps and resistors. I replaced the micas. Nothing helped. I started to suspect the horizontal oscillator transformer. But, I noticed that the DC level on the grid of the 6AU6 control tube was -1V when it should have been -3V. The 6AU6 is used as a reactance tube to control the frequency based on the output of the phase discriminator. -1V put it at one end of it's control range so it could only adjust the frequency in one direction if the free running frequency was set correctly.

The bias is determined by dividing down the -125V supply. First they divide it down to -30V with a low impedance divider then down to -3 with a 10meg and 1meg in series. I checked those and they were o.k. I was getting close to modifying it to give the right bias when I decided to swap the 6AU6 even though it tested as new and seemed to work. Well the bias went to -3V with the new tube and I was able to align the horizontal sweep as per the service manual. The grid on the 6AU6 was drawing 0.2 microamps at -1volt. My tube tester isn't going to notice that.

Now the only problem I have is with the FM. Although it worked great in the beginning, it is now fading out after 4 minutes. It runs for 4 minutes after turning on and then suddenly the volume drops.

I've replaced two micamold caps. One was leaky, the other was o.k. Some resistors are out of spec, but I don't think they're at fault.

What is curious is that the AM function works fine even when the FM has dropped in volume. They both use the same circuitry except different IF transformers and osc frequency. There must be a clue in this.

You can see the schematic for the radio section on the last page of:

https://www.msu.edu/~yurkon/Sylvania_9-2_Sup1.pdf

This is getting to be really frustrating. I swapped all the tubes in the radio after my experience with the horizontal 6AU6 but it didn't make a difference. Any suggestions for what to look for would be welcome.

I'd like to get it off my bench so I can work on my alignment generator and get it working. I want to touch up the alignment since I had to rewind one of the video IF transformers.

I'm also working on making a bezel for the 12" version of this set. A friend drew a mold up for me based on my measurements. I didn't notice however that the had made the face a cylinder instead of a sphere. It wasn't obvious in the preview. It became obvious when the shop I'm using tested their programming on a shape board.

If I'm able to cast a 12" bezel then I'll put a 12LP4 into the chassis. It should really be a 12VP4 but I'm unlikely to find one of those. I'll have to add a screen bias supply. One of the 16" Sylvania shows a circuit to do that, based on this power supply.

This is basically changing it from a 1-076 model to a 1-128 model. I have the cabinet from my family's 1-128, just nothing is left of the electronics. The 1-108 chassis was used in both. If I can't successfully cast a bezel I'll refinish the 1-076 cabinet and stick with it.

John

Have you re-capped the entire set?
Bill Cahill

Have you re-capped the entire set?
Bill Cahill

Bascially. Any that I didn't change were tested. All paper capacitors were replaced. I didn't change any ugly looking ceramics based on feedback from the forum and the fact that a sample of them that I did test, tested good.

The radio section is comletely independant except for the 6AU6 1st AF and 6Y6 power amp which is shared by the TV. The problem only occurs with the FM. The TV and AM audio are fine.

There was only one electrolytic in the radio section and I changed that in the beginning since it was shorted. I changed the two micamolds that were in the radio. There are other micas that aren't micamolds. I'm hoping it's not one of these micas because I'd have to remove most of the other components just to get at them.

Also, I've checked the HV to the radio and it doesn't change. There should be 215V on the plates but it's 238V. I've tried lowering it by running the set on a lower voltage with a variac, but this doesn't change the fading.

John

Found the FM fading problem. Had to resort to using component cooler. It's the 2nd 10.7MHZ IF. It looks exactly like the Ktrans that Robert Casey repaired. I suspect it's the same problem.

Anyone have a 122-0011 Sylvania IF or Merit FM-254 you're willing to part with?

John

I found an FM-254 and ordered it, but decided to repair the original IF instead. The FM-254 would have been too difficult to use because of the pin-out.

In the first photo you can see the problem with the mica capacitor. Although it looks like silver migration might have been the problem, it was actually a break in the silver on the bottom half that you see. It appears that the mica was bent when installed. It was actually tuned to work with it open. Then it would eventually make contact as it warmed up and detune.

I measured the capacitance on the good side at 23pF. Just for the fun of it I measured the thickness of the mica which was 0.045mm, the area that forms the capacitor as 3.5mm x 5.5 mm and calculated the capacitance assuming a relative dielectric constant of 6 for mica. I came up with 22.7pF.

I installed two 22pF silver mica capacitors internally. You can see the result in the right hand photo. I think most people install them outside during the repair, but there was room and I was confident of the value that I needed.

The FM works great again and is now stable. It only took a minor touch-up on the alignment on the side that was good, on the other side I had to back the slug out many turns. I think the IF had been this way since it was made.

I'm glad that this set didn't have any serious problems to solve since it was my first restoration. Even the minor problems I had to deal with might have stumped me if not for the wealth of information that many of you have made available on your web sites.

John

John , you have done a great job .
Such a neat set to restore .
If you ever need a volume control , I "might" have one .
I've got a big box of different ones that were salvaged by a TV / radio guy back in the day.....

John , you have done a great job .
Such a neat set to restore .
If you ever need a volume control , I "might" have one .
I've got a big box of different ones that were salvaged by a TV / radio guy back in the day.....

Thanks for the offer. So far the accidental repair by loud sparks is still going strong. I just couldn't believe my luck. I thought for sure I would have destroyed something.

John

Since I won't have the set back in a cabinet by the time analog TV is history, I thought I should shoot a couple of photos of over the air broadcasts.

The on the left is Channel 12 in Flint Michigan, 36.1 miles away. The one on the right is Channel 6 in Lansing about 7.4 miles away. For channel 6 I don't even need a rabbit ear. Just 2" of wire.

The key-stoning you see in the right hand photo is because I'm close to the TV and at a slight angle.

I think the slight fuzziness is because I need to align the video IF. I have to finish restoring my Hickok alignment generator first.

I've also been slow in starting on the cabinet because I've been tracking down all the minor problems I could find. One was a crackling in the sound as the set warmed up. I thought I'd find that one of the electrolytics that I decided to keep was failing and I'd have to swallow my pride.

It turned out to be the 6Y6G audio output tube. I swapped it and the crackling went away. Swallowing my pride will come later.

I wonder if there is a heater to cathode short developing with it. The tube is coated so I don't think it was secondary emission from the glass.

John

Nice picture on the Sylvania! I havent forgot about the turntable John...i'll look this comming week and let you know.
-Tony

I just tried to attach images and got an upload error. I'm now trying to see if I can even make a reply to my thread...

John

I just tried to attach images and got an upload error. I'm now trying to see if I can even make a reply to my thread...

John

I can't attach files either, but it seems I can respond at least.

Here are the photos again of the bezel/mask mold that I'm making. The left photo is the 10" bezel, the center is the 12" rear half of the mold after machining and the right is after my attempt at polishing.

John

John, how on earth did you make that mold? It looks incredible!

John, how on earth did you make that mold? It looks incredible!

Thanks. I took measurements from the 10" bezel and used the radius from the datasheet for the 12VP4 CRT. I drew the cross-section that I wanted and then a friend drew it up in SolidWorks. Another shop has a new employee and they thought it would be a good training/learning experience for him. It's not a simple part even for CNC. He learned a lot and I gained a part. The risk for me was having to possibly keep replacing material if there were problems.

So, I really lucked out. I only had to pay for material. Our own shop is way too busy to even think about doing anything personal. Especially this complicated. I'd probably have gotten in trouble for even asking.

I was looking at having a rapid prototype company do it, which would have cost a fortune, when this opportunity came up.

The polishing I did by hand using micro-mesh mx and wet sanding it through all the grades, then using Mother's aluminum polish. I was worried that it wouldn't work as well as Simichrome or Wenol polish, but it seems to work as well.

John

More miracles. Or maybe there are more early Sylvanias out there than I realize.

Roger Dreyfoos noticed my attempt at making a mold for a 12" bezel and remembered he had picked up some freebies of some sort at CHRS flea market. It turned out one of them was a 12" NOS Sylvania bezel for the 1-108 chassis! He was kind enough to pass it along to me. Thanks Roger! :banana:

I will finish the mold, just to see if it works. Also in case anyone should need a 12" bezel similar to this.

Now I can complete my goal of having my childhood TV console again. I just need to pick up the 1-128 cabinet from my brother's place. Of course I'll have a 1-076 cabinet that's empty. No aquarium for it though. I'll just hang on to it in the hopes that I eventually find a chassis for it.

I can't blame my dad for converting his to a linen cabinet. It was a perfect use for it and he did a great job of installing the chassis and record player into the rec room. It's only when things get old that we start thinking about preserving them in their original form.

"The Wonderful World of Disney" was one of my favorite shows that I watched on the Sylvania. I've been hoping for many years to eventually find a set and the way things finally started to fall together it seemed as though a wish was being granted. Thus the title...

John

I forgot the attachments. Here's the 10" and 12" bezel.

John

I picked up cabinet from my parent's 1-128 Sylvania over Thanksgiving. It survived the trailer ride well.

http://www.videokarma.org/picture.php?albumid=510&pictureid=2896

The console is supposed to look like this:

http://www.videokarma.org/picture.php?albumid=510&pictureid=2897

Here's the outside front:

http://www.videokarma.org/picture.php?albumid=510&pictureid=2891

The finish isn't too bad. Where it's thin it has a more reddish color.

http://www.videokarma.org/picture.php?albumid=510&pictureid=2894

My dad had converted it into a cedar chest to store linens.

http://www.videokarma.org/picture.php?albumid=510&pictureid=2893

http://www.videokarma.org/picture.php?albumid=510&pictureid=2892

Restoring it to use the 1-108 chassis that I have that is common to the 1-076 10" and 1-128 12" consoles shouldn't be too difficult.

I had ordered some NOPP film from a US company, but the actual shipment came from Jakarta and was boxed in some fairly high grade luan/mahogany plywood. I'll see if that works for the panel. I also need to pick up some small pieces of solid mahogany.

The biggest problem is that he cut slots in the trim for the cedar.

http://www.videokarma.org/picture.php?albumid=510&pictureid=2895

Since the finish is so dark, I may be able to just fill it and stain it. The recent thread on molding trims/molding will be helpful here.

If you were really observant you'll have noticed that there were supposed to be rosettes at the upper corners which don't appear on my cabinet. I vaguely remember them being there, but there are no signs of them being removed. I think they would have been attached rather than milled into the boards. The rosettes are raised and it would have required milling much wood away. They may have even been metal like the pulls.

The style of this cabinet is Hepplewhite, or so claims Sylvania.

I'm getting closer to getting my childhood set finished. I may convert the 1-076 cabinet into a cedar chest using the cedar from this cabinet after I'm done. I'll never be able to find parts to make a complete 1-076 or 1-128 without gutting one of them. Fortunately, beside the cabinet the only things that are different between the two are the CRT, band to clamp the CRT, and the bezel.

John

You are doing an awsome job John. When this is finished you will accomplished something very wonderful, especially considering the obsticles that have been in your way.

This is the first I have seen the postings about the mold you had made. What a spectacular piece of machining. Must have taken a lot of work to polish that to such a beautiful mirror finish.

If you look around at some of the woodworking web sites, I think you may be able to find wooden rosettes that might approximate the ones that are missing. Just google wooden rosettes. The first hit I got can make 13,000 different historic designs.

Bob

Are there pictures in post #65 that my browser does not see?

Same "no pix" problem here. Maybe they didn't survive the trailer ride? I PM'd John.

Roger

Are there pictures in post #65 that my browser does not see?

Yes there are pictures. This is my first attempt at posting using images from an album. I thought I could leave the album private. Apparently not, so I've made it public.

Please let me know if this works now.

John

Looking good now! Nice set!:banana::banana::banana:

jr

I've micaculously got the pix now. Now here's my opinion. You don't need no stinkin' rosettes. Seems quite possible that someone decided (perhaps at the factory) that it looked as good or better without the rosettes.

Or, maybe the Sylvania legal department decided that as add-ons, a little kid could figure out how to take them off and swallow one.

One person's opinion,

Roger

I've micaculously got the pix now. Now here's my opinion. You don't need no stinkin' rosettes. Seems quite possible that someone decided (perhaps at the factory) that it looked as good or better without the rosettes.

Or, maybe the Sylvania legal department decided that as add-ons, a little kid could figure out how to take them off and swallow one.

One person's opinion,

Roger

After looking more closely I can see where one was glued to the left side. I don't see any evidence on the right side.

I'll leave this for last and decide then which way I prefer it. I tried a quick search per Bob's suggestion. I need to find one that's 3/4" in diameter. Most seem to be much larger than this.

John

I've started to remove the cedar lining. Fortunately my dad didn't glue them in. They're tongue and groove and were nailed as you would flooring with small brads. The nail holes are almost invisible.

I was happy to see the tube chart is still there. I'm a bit confused though. They went to the effort of making a label especially for the model 1-128. That uses a 12" CRT. Yet they show both the 10" 10MP4 and 12VP4 as possible CRTs. Why show the 10MP4 when it was used in the 1-076?

It's also curious that the "UL" label was inked out. I wonder if it didn't meet UL certification?

I'll take more photos after I remove all the cedar and figure out what's missing. I found one surprise already. Maybe it'll be clear after I remove more cedar.

John

Hmm, that is weird. Never saw a UL label inked out.

The finish on that cabinet doesn't look bad at all. I'd bet a little touch up (and maybe a couple coats of lacquer if it's worn) would do wonders.

Well, I checked the 1-076 cabinet and the UL stamp is inked out on it too.

The first picture on the left is the inside of the phono side in the 1-076 cabinet. The rear panel is Masonite. I was surprised to see that they used regular plywood on the right where they separated the TV from the phono. The left side is mahogany veneer. In the 1-128 they used mahogany veneer on the right side too. I had thought they would also use it for the back, but I think Masonite might actually look better because of the uniform surface. The color of the Masonite looks much different than the wood in the photo, but to the naked eye they are quite similar. Looking at the photo in the Sam's, it appears that they used Masonite in the 1-128 model also.

But, the record changer is supported differently. In the 1-076 it hangs into the speaker cabinet. In the 1-128 it's above the record storage area and sits on a platform. The board to support the changer fits into a dado on the right side and is screwed to a rail on the left side. It also sits on a board at the front of the cabinet. I'm not sure if they used Masonite or plywood which sat on the bottom rails to separate the space between the changer and the storage area.

The photo on the right shows the rosette that is on the 1-076 cabinet. I believe it's the same as the missing ones on the 1-128. I suppose I should make a mold of it to replicate it. However, I'm tempted to get a Carvewright to make one out of wood. But, unless I can come up with a number of other uses for the Carvewright, that would be a silly expenditure.

John

Roger Dreyfoos suggested that the rosette was made of Repwood and not carved. After examining it closely, I'm pretty sure that's correct.

That will make it easy to reproduce and has killed my immediate desire to obtain a Carvewright. I've ordered some Equinox 35 silicone putty to take an impression and make a mold.

I've also ordered some Mohawk toning lacquer in three different shades of mahogany to try out. Hopefully one will match the existing finish.

John

Here's a test of making a mold to copy an appliqué. I decided to try it on an appliqué on a Majestic 71 radio. It's about 1" long. The radio was refinished by the previous owner and that might account the the old finish around the piece.

I mixed up Equinox 35, which is a silicone putty and applied it. I removed it after letting it sit for the demold time of 7 minutes. I was surprised to see that no air was trapped.

I then mixed up some Bix staining putty and used that to copy the piece. The rough surface is due to micro bubbles that I didn't realize had formed when I added the water and mixed up the putty. If I use this in the future I will need to degas it. Otherwise I might use an epoxy instead.

The final photo shows the part next to the original after spraying with lacquer. The difference in color is because I only had mahogany toned lacquer when the original is walnut.

The rough surface is unacceptable so I will need to work on this some more, but the mold was easy to make and is more than satisfactory.

John

Awesome! Where did you get that Equinox 35?

I got it from TFB plastics since they're close to me.

http://www.tfbplastics.com/catalogsearch/result/?q=equinox&x=25&y=10

The manufacturer is Smooth-On http://www.smooth-on.com/Architectural-Rest/c1236/index.html

John

I've been holding off replacing the 10MP4 with a 12LP4 since I was having trouble finding the right CRT socket. I collected a bunch of brighteners to steal the socket from, but they are quite identifiable as brightener sockets due to the green cap and mediocre quality. I would have had to splice the leads also which I didn't like the idea of doing.

I finally obtained a NOS EBY CRT socket. It has nice long leads and looks like it belongs. It does have an extra lead for CRTs that use electrostatic focusing. So, I have the option of cutting off the blue lead or running it down to the chassis and just not using it. For some reason, I'm inclined to do that. Some day I might find a 12VP4 and then I'd put the old socket back. And I could save the new socket in case I come across a set that needs it.

I finally had to give up on my old Pioneer RPTV. I replaced it with a 60" Mitsubishi DLP which I mounted on the wall. I now have space to put the Sylvania console under it. I'll bring the cabinet in this weekend and be able to work on it when time permits.
John

I'd keep that blue lead too - never know when it might come in handy.

I replaced it with a 60" Mitsubishi DLP which I mounted on the wall.

Which one? The picture quality of the 65" WD-65831 I bought last year is stellar, and I got it for a song at Best Buy.

Which one? The picture quality of the 65" WD-65831 I bought last year is stellar, and I got it for a song at Best Buy.

The WD-60C9. Not as high end as the 831 series, but I'm very happy with it. With it set for natural, the color is quite good. Though the blues tend to be quite electric in some scenes. I'm tempted to try the advanced set up.

I wish I knew where the vertical center of gravity is. Since I have it mounted high enough to go above the Sylvania, I'm tempted to tilt it forward by 10 degrees.

John

Whoops, just looked at the back and it's actually a WD-65735. Went to the Mitsu site, they now have 82" sets! Looks like it's trade up time, huh? :D

Whoops, just looked at the back and it's actually a WD-65735. Went to the Mitsu site, they now have 82" sets! Looks like it's trade up time, huh? :D

Maybe if you have a 20ft deep living room! :D

John

Yeah, no doubt!

Anyhow screw HD, back to watching South Park on the Philco! :)

Here's a thread where making a mold to reproduce an item like that rosette is explained.

http://www.videokarma.org/showthread.php?t=246388&highlight=mold

Duplicated

I've added a circuit to supply the screen bias needed for a 12LP4, that uses the existing 170VDC supply and a 135 V. rms tap. It comes out to 255 VDC which is really close to the 250 v typical G2 operating point of the 12LP4.

After replacing the crt connector and adding the circuit I tried operating it with the 10MP4 to make sure I didn't mess anything up. It works fine. In fact, I used to have a minor problem with a crawling horizontal and vertical distortion in the image that I had thought was from the damper tube filament transformer which is mounted near the neck of the CRT. This problem has disappeared. So has the sync buzz you get when tuning, or have text displayed on the screen. In fact the sound quality is dramatically better.

There is no reason the circuit I added should have any effect on either the sweep or the sound. Guess I shouldn't complain though.

The next step will be to try the 12LP4. I'll take photos of the circuit addition when I do the test.

I got rid of my old rear projection set and mounted a DLP on the wall leaving space under it for the Sylvania console. I've attached a photo of how it'll be set up. The cabinet is empty at this point.

John

I've attached a photo of the booster circuit I added. It's on the board with the orange drops.

Close, but no cigar. :tears: Yet. :thmbsp:

I tried mounting the 12LP4. I raised the scanning bridge to the next higher set of holes which centers the yoke on a 12" CRT. However the 12LP4 is 3/4" longer than a 12VP4. The yoke has a large adjustment range to accommodate both the 10MP4 and the 12VP4, but not enough to handle the 12LP4. I was about to give up and consider staying with the 10MP4 and then having to decide whether to mount it in the 1-128 cabinet or the 1-076 cabinet. 10" would make most sense in the 1-076, but the 1-128 cabinet is the one our family kept.

But, not all is lost. It turns out that the chassis has another set of holes for a 12" CRT located 3/4" farther back that would make the 12LP4 fit perfectly. This must be the Swiss Army Knife of chassis. It was used for a large range of sets including one that used a 16LP4 CRT (at least the bridge was). The 16LP4 version has a boost circuit for the screen that uses a 6X4. There is a hole already punched for it in the bridge. I could have gone that route, but I would have had to reroute too many wires. It would have been a lot of work and the work would have been obvious. So, I used a silicon diode version of the circuit that I could hide underneath.

But, the bell of the 16LP4 is 4 inches longer than the 12LP4. I'm guessing but it seems that they had designed the chassis to be able to use the 12LP4 but never built them with it. The 12VP4 was probably less expensive, especially since they could leave out the 6X4.

When I do move the bridge back, the cross brace may not have a set of holes for it. It had one for raising the bridge, but I suspect there won't be a matching location for both raising and moving the bridge back. I may have to make a different cross brace. Not a big deal since it's just a flat strap with a bend and each end.

John

I installed the 12LP4 tonight by moving the bridge to the next set of mounting holes back. By the way, there are another set of holes that would accommodate a 16LP4. That's really stretching a design.

I will have to make new side straps because of moving the bridge back. They're 3/4" too short now. To my surprise, the cross brace still fits.

The raster was shifted to the left. I was able to center it with the horizontal center control, but the raster is out of focus on the right. I had to greatly reduce the focusing field to get it to focus, compared to the 10MP4.

I've included a photo of the dot pattern to show the focus, though it's obvious in the movie photo.

I just noticed that the focusing magnet is pretty far off center vertically. It's centered horizontally. This doesn't seem to match the focus issue.

The yoke is very slightly off axis. It's such a small amount that I can't believe it's the cause. I'll try moving it to see what happens.

The GE data-sheet for a 12LP4 says the center of the focus magnet should be 4-1/2" from the reference line. The Sylvania data-sheet for a 12LP4 says it should be 3-1/4" from the reference line. Mine is 3-1/2" from the reference line. I wonder if I should move it back a bit.

Any suggestions as to what might be causing the left shift and the bad focus on the right would be welcome. It seems to be unaffected by the ion-trap position.

John

I think that I also see some keystone from left to right (yoke alignment?) or perhaps some voltage shifts? Are power supply voltages, boost, HV constant ? or do they change with the horizontal position of the beam?

jr

I think that I also see some keystone from left to right (yoke alignment?) or perhaps some voltage shifts? Are power supply voltages, boost, HV constant ? or do they change with the horizontal position of the beam?

jr

The key-stoning was there with the 10MP4 also, but it didn't have the focus issue and it was centered horizontally. I'll have to check the supply and the boost. The HV will be constant if the power supply is since it's an RF oscillator type. At least it wouldn't be coupled to the horizontal.

It could be the power supply. Since I had to make a large horizontal center adjustment, and the pot that does that also drops the 180V to supply 170V to other sections, it could now be affecting the 170V that I boost to 250V. The 170V is also supplied to the vertical output stage.

Until I'm able to secure the CRT I won't be able to do any measurements under the chassis.

It's probably not related, but right where the screen gets blury is where the right edge of the scan stopped until I recentered it.

John

I scoped the G2 voltage and there is minimal ripple. Perhaps a volt. The G2 is +254V. This shouldn't account for the focus problem. Also, since this is derived from the +180V supply, it shouldn't be causing the keystoning either. I can't get to the -125 supply yet to check it, but it could have ripple causing the keystoning.

The gun does not appear to be a slashed field type. It doesn't seem bent either, but I can't see enough of it to be sure either. This is a rebuilt 12LP4 and the gun is different than the original type. If the end is offset like I see in some diagrams, that might be causing the left shift that I'm having with the raster. I've tried centering the focus magnet better and playing with the yoke with minimal improvement.

Since the gun is different I started to wonder if I needed to use a single field trap instead. The instructions that came with a Miller adjustable single field trap says that CRTs up to 10" or 12" having a straight gun, generally use a double ion trap of 38 gauss. I think by straight gun they mean one with a slashed field.

Then they go on to say that CRTs of 14" to 17" having a bent gun, use a single ion trap of 35 to 45 Gauss. Larger CRTs use a single ion trap of 45 to 55 Gauss.

Since it doesn't appear to be a slashed field type I decided to try a single field type. I had to adjust the field down to 35 Gauss for best results. This is the same strength as the double field trap that I have. With it adjusted to the best position I wasn't able to do any better than I did with the double field trap. With both of them I have to butt it up against the base. I get the impression that it might be better to even move it over the base. Perhaps the field is too strong, but I can't adjust the adjustable trap any lower than 35 Gauss.

The HV is at 8.8KV. The manual says it should be between 9.5KV to 7.5KV depending on the brightness setting. I heard some corona in the coffee can today so I've got to find that. I've suspected it in the past, but I've never been able to see it. I was also afraid of getting my nose too close.

I have another 12LP4 that is rebuilt that I can try. I noticed a strange charging effect when I used the single field trap. I'd adjust it, it would be o.k. for a few seconds and then drift. This didn't happen at the best position though.

If it's a matter of not having the slashed field type gun, I have one unrestored set that has a good original 12LP4 in it. I hate to take it out but I may have to eventually try that.

John

Perhaps it is indeed a straight gun...Do you get any beam to the screen with NO magnet?

"I have one unrestored set that has a good original 12LP4 in it. I hate to take it out but I may have to eventually try that."

It seems that many times the most difficult experiment yields the most useful data!

Since you mentioned charging effects, I had another terrible (perhaps far fetched) thought about the key-stoning/focus... since the tube is not aluminized, is the landing energy of the beam constant as it travels across the screen ? Is it possible that the phosphor surface discharges somewhat during retrace? :scratch2:

jr

Perhaps it is indeed a straight gun...Do you get any beam to the screen with NO magnet?

"I have one unrestored set that has a good original 12LP4 in it. I hate to take it out but I may have to eventually try that."

It seems that many times the most difficult experiment yields the most useful data!

Since you mentioned charging effects, I had another terrible (perhaps far fetched) thought about the key-stoning/focus... since the tube is not aluminized, is the landing energy of the beam constant as it travels across the screen ? Is it possible that the phosphor surface discharges somewhat during retrace? :scratch2:

jr

O.K. I do get a raster with no magnet. I tried the other rebuilt CRT and it behaves the same way. The raster is best without the magnet. However it is still badly focused on the right side.

The keystone is much reduced without the ion trap. I did have a keystone with the 10MP4 also. I suspect it is the -125V supply not being rigid enough, but I haven't tested it yet.

In defense of your odd theory :thmbsp: when I had the keystone effect pretty bad with the 10MP4 I thought about charging since the raster would move if I got my hand near the front of the CRT. I blew on the CRT expecting moisture to drain any external charging. The raster blew up and disappeared for a second then returned with only a tiny keystone. I think the small keystone is a supply issue.

I did some research and the only way I can see that I could get a raster without an ion trap is if G2 and G3 are at the same potential. I think this would be extremely unlikely. Especially for both CRTs.

I will have to try the old 12LP4 that is in a Sonora that is further down the restoration queue.

BTW, I did look up the specs for a 12LPC. Although it is aluminized, from the factory it still requires a dual field ion trap.

I also found this page where they converted a set from a Triode to Tetrode (http://www.thevalvepage.com/teletech/tube_rep/tube_rep.htm) CRT. They had to reduce the focusing field, which I also observed.

Something else that is happening now is that I get a bright spot for a couple of seconds after turning the TV off. With a gun that requires an ion trap, the electrons have to have the right velocity to make it out of the gun. As soon as the HV drops they get lost. But the straight gun without a trap doesn't filter by velocity

John

I would try moving the focus magnet. Specs for a 12LP4 call for a double-field ion trap, but once they're rebuilt, it seems anything goes. All of the rebuilt CTRs that I've seen used a single-field ion trap. For that reason, I would ignore the focus magnet orientation specs and adjust it for best pic.

I would try moving the focus magnet. Specs for a 12LP4 call for a double-field ion trap, but once they're rebuilt, it seems anything goes. All of the rebuilt CTRs that I've seen used a single-field ion trap. For that reason, I would ignore the focus magnet orientation specs and adjust it for best pic.

Thanks for the suggestion. I tried moving it further back and that helped with the centering, it improved the focus a little at the top and bottom, but the right is still bad.

It could still be a geometry problem, but that it no longer requires an ion trap worries me. Unless the vacuum is extremely good I'd eventually get an ion burn.

John

No pictures, yet I don't have any time left to work on it today.

I tried the 12LP4A from the Sonora. It was made by NU-Videon or something like that. It was better, but basically behaved the same except that it really does need an ion trap.

Using the double field trap I wasn't able to adjust it properly. At the brightest position there was a shadow. It was not as bright at the position that got rid of the shadow, but the focus was good.

I then used the single field trap that was on the tube. This tube really does require a double, but the single field gave the brightest image without the shadow. The CRT is dim and blue opposite the anode connector. It looks a lot like the damage described in the article I posted about adjusting ion traps where the beam hits one of the electrodes and sputters material on to the screen. I fear that's a result of it's being used in the Sonora with a single field trap.

I think the offset raster and bad focus on the right is a geometry problem. I earlier posted that I was surprised that the cross brace still fit after moving the bridge back. Well, it is slightly off shifting the bridge to the left. I'll need to make a new brace.

It may also account for the bad focus on the right. When I mis-adjusted the ion trap I could get a good focus everywhere, dim raster though. This makes it seem like a depth of field problem. When the ion trap is mis-adjusted, only a small portion of the beam exits the gun lowering it's acceptance. That is, there is a smaller range of angles of electrons leaving the gun. This gives a larger depth of field. With a small depth of field the focal plane has to be aligned properly to be in focus everywhere. With a large depth depth of field the focal plane can be tilted with respect to the screen and still have a good focus.

This is conjecture and I'll have to see what happens when I get the bridge back into its proper position.

I'm still worried about the rebuilds not using an ion trap any more though. I wonder how long they would last this way.

John

I tried the used 12LP4 from the Sonora again, mostly to take a photo and try having the bridge in the correct horizontal position. That's the photo on the left. Ignore the vertical non-linearity, my bad.

The bridge position didn't help the focus. It did turn out to be related to the depth of field of the focus of the beam, but not because of a rotation of the screen around the focal plane.

You'll notice a bluish stain in the bottom right corner. This is opposite the HV connector. The HV connector is on top in the Sonora so this stained region is outside of the normal scan in that set. In the Sylvania I have to have the connector at a 45deg angle so that's why it shows up here. Its a really odd stain/ion burn because when you look at it closely you can see that the phosphor grains are coated on one side. I have no idea how this occurred.

The RCA data sheet for the 12LP4 gives more information than the others. It gives focus and ion trap strengths for 9KV and 11KV. The proper field strength for the ion trap at 9KV is about 14% less than it is at 11KV. That means it should be 30 Gauss instead of 35 Gauss. That's probably why I can't adjust the double field ion trap properly because I'm at 8.8KV. If I try this CRT again I'll make a shunt for the trap to reduce its field. I should be able to do at least 9.5KV with the Sylvania. That's supposed to be less than the peak value obtainable. Perhaps I missed something when I worked on the HV section. Maybe the RF transformer is getting lossy. The Sylvania manual also says to try different 6Y6 tubes since they're not all created equal. Or, maybe it thinks it's a Philco. ;)

Since the focus field should be smaller at 9KV and it should be smaller also for a tetrode CRT than a triode CRT I decided to try to reduce the focus field more than I was able to easily do before. I was afraid that I would have to add more shunts, but there was still some adjustment room left.

Now the focus isn't perfect, but it's fairly uniform across the screen. There is some astigmatism. The focus magnet is close to the yoke at the moment. I will move it farther back which should help and eliminate the shadowing on the left.

The Sylvania is capable of better resolution than you see here, though it's not bad for a set of this vintage. It's mainly a focus problem. If I can get the HV up to 11KV I think things will look much better.

They did a really good job of rebuilding the two CRTs I have. They have excellent emission and are nearly identical in performance. My only concern is that they no longer use an ion trap.

John

Great progress! :banana::banana:
Wow what a saga! So where did the Horizontal position pot end up ... still pushing the raster hard to the right? Another 1 to 2 KV should sharpen things up a bit if you can get it and still get enough horiz and vertical scan. Does the "shunted" focus assembly produce a fairly uniform field?

jr

The pot is pretty much in a neutral position now. Basically where it was for the 10MP4. I have more than enough scan width left over in both horizontal and vertical.

I don't know how uniform the focus field is. I'll have to borrow a Gauss-meter. I didn't add any shunts. There are two versions that this same chassis uses. One has two adjustable shunts and another has only one. This one has two so it probably helps to keep the field uniform.

John

Or, maybe it thinks it's a Philco. ;)

Hey! My Philco resembles that statement. :smoke:

Scotty is a great guy! He says the SW30 is the correct gun for a 12LP4, but it is a straight gun and should only be used for an aluminized 12LP4. Since my CRTs aren't aluminized a bent gun should have been used.

He is willing to rebuild the two CRTs again for only the cost of rebuilding the two bent guns. This is more than reasonable since I would have had to pay the rebuilding costs for the guns anyway since bent guns aren't available.

I can highly recommend Scotty for any rebuilding. Also, the emission for the two CRTs were perfectly matched and in my opinion atests to the high degree of control that he has in the rebuilding process.

John

Hey! My Philco resembles that statement. :smoke:

I was wondering if I'd get a rise out of anyone. :D

"rebuilding the two bent guns"

Wow! How does he get the old cathode out? Grind/cut away the retainer ring? Or perhaps he somehow replaces the whole cathode/grid cup assembly and re-aligns it? :scratch2:

Hats off to anybody that can do this.:thmbsp:

jr

"rebuilding the two bent guns"

Wow! How does he get the old cathode out? Grind/cut away the retainer ring? Or perhaps he somehow replaces the whole cathode/grid cup assembly and re-aligns it? :scratch2:

Hats off to anybody that can do this.:thmbsp:

jr

He has someone else do it.

When I took mine apart I gound the three spot welds. That left three small holes in G1. I don't think that would affect the operation.

I hope Bob or John correct me if I'm wrong, but for rebuilding their 15GP22 guns Bob edm's the retainer/cathode holder out. That leaves G1 intact. I think they made a tool to stamp out new retainers.

John

I swapped the audio and HV 6Y6 tubes and the HV went from about 8.8 KV to 10.2KV. The audio has crackling noises so it's pretty clear that there is leakage in that 6Y6.

That helped the focus issue a bit. It's livable, but I think I may have a problem with supply ripple or ringing in the horizontal section. The vertical focus is quite good most everywhere now. But the horizontal is off. When I reduce the width to what it was with the 10MP4 the horizontal resolution improves. It's not just a magnification issue because the test pattern resolution improves.

Something else I meant to ask about; when I received this set the yoke was 5-10 degrees off axis. I thought it was just misadjusted, but after restoring the set that was the position it has to be in for the scan to be horizontal. It's unchanged between the 10MP4 and 12LP4.

Is it common for yokes to need to be adjusted this way? If not, what could cause it?

John

I forgot to mention that after getting the HV back up to where it should be, the corona sound got louder and I do smell ozone. It doesn't happen with the coffee can off though. It looks like there is a discharge between the cap of the 1B3 and the can, based on burn marks on the paint. The cap seems smooth, but I guess I should try polishing it more.

About the yoke rotation, the yoke is in a steel cradle that is half a tube. A solenoidal magnet will rotate the scan. Since the focus magnet was very close to this it may have magnetized it and it could be acting like a solenoidal magnet. I'll have to try degaussing it the next time I have the CRT out.

The vertical centering magnet assembly was falling apart from age, so I made a new holder for it out of fish paper. The red paint on the ring indicates the North pole of the magnet.

The disk on the left is the original one.

John

Since I had to move the bridge back to accommodate the 12LP4 I had to make longer brackets. The second one from the bottom is the original one. The bottom one is one that I bent from sheet stock. The third from the bottom is one that a machinist friend made. It looks the nicest, but even though it is the same thickness, it is too stiff to bend. I may have to try annealing it.

The top object is the original cross brace and the one below it is the one I made. There is very little difference between them other than the bend angle and a slightly different hole location.

John

I also had to make a longer strap. I found a piece of strapping in a dumpster that was the right width and thickness. I cut a piece of steel for the retaining end and took a 10-32 stainless socket head cap screw, but the head off, and beat it with a hammer to make the other end. These parts are shown in the first photo. The second photo shows the original strap. The next two show the ends of the strap after spot welding the pieces on and the next two show the completed chassis after assembling the parts.

The original CRT had a brown paper strip glued around the CRT under the strap. It was also glued to the strap. I guess this was to provide some minimal protection for the CRT and keep it in place. Although not as original, I used cork. It works well and holds the CRT securely. I'll trim it up after I am satisfied with the CRT adjustments.

You can pick up a resistance welder on eBay for almost nothing. They come from China. I can't figure out if they are a knockoff of the ones that Hobart and Miller sell, or if they supply Hobart and Miller. If you do get one off of eBay, don't expect it to work out of the box. It takes some adjustments.

I also wanted to have a fire extinguisher nearby in case a spark caught something on fire. If you have a cat, don't expect the release pin to be in the extinguisher when you pick it up. I can't figure out where Schatzi has hidden it! :dunno:

John

Since I have to replace some missing pieces of the cabinet I needed to learn how to do veneer work. After doing some reading using a heat activate glue sounded like the easiest. It's safe, water based, and you can do it in your living room. You can align pieces without them sticking until you are ready.

I missed the first photo. I forgot to load the film (CF card).:withstpd:

I taped the veneer down to keep the glue from getting on the face. The veneer is cut larger than the plywood. I've already applied the first coat of glue to the plywood in the first photo, but I didn't apply it to the veneer yet since it's a paper backed veneer, it won't require two coats. The glue needs to dry for 20 minutes.

I was surprised at how easy this process is.

In the second photo I've applied glue to the veneer and the second coat to the plywood.

The third photo shows the veneer setting on top of the plywood ready to iron on with medium-high heat.

The last photo shows the finished product after trimming the excess veneer. At this point it would be ready to do any cutting to final size and drilling any needed holes.

It needs to sit for 24hrs before doing any finishing. I will try that next to see if I can match the existing finish.

John

Very interesting - thanks for detailing your process.
How did you trim the excess veneer ?

I have never really had good luck with the iron on veneer. I use very thin paper-backed veneer with contact cement. I typically reveneer an entire panel, or if it will be noticeable, redo a facing panel as well, so they will properly match. This of course involved stripping the entire cabinet. Maybe it's overkill, but by the time you are into that level of woodworking and preparation, you just may as well take it all the way.

Banderson-to trim veneer, I pretty much use whatever is sharp. I keep an Exacto knife and a variety of other razor blade tools, as well as a double edged razor blade like you find in the old safety razors-they are deadly sharp, and perfect for those tight corners. I also sand down the edges when I am done trimming. There are tools on the market that are also made for just such jobs as well, although they are really only good for straight edges.

Banderson, I used a utility knife. I did pick up a band trimmer, but it doesn't work well across the grain. Since I'll be working with the panel later, the trimming doesn't need to be precise. But, the utility knife turned out to be surprisingly precise.

Leadike, are you talking about the iron on veneer that already has the adhesive applied or the type of product that I used? I find that this HEATLock works really well. It's thermoset so heat doesn't help if you try to remove it later.

John

I decided to try using the method of wiping on orange shellac with a cloth to seal the wood and fill the grain. Photo one shows the materials. The shellac was cut with ethanol.

The shellac was wiped on trying to wipe most off of the surface. It was then sanded down to the surface. Several coats were applied. The result is in the second photo.

I then used Mohawk Utra Classic Toner, Brown Mahogany, aerosol lacquer to finish the board. The last photo compares the color of finished sample to the cabinet. I will be making a front panel to mount the bezel and I would like the panel to match the rest of the cabinet as closely as possible.

Being a bit red/green color blind I'm not sure how well I've done that.

I'm a bit confused about the cabinet. It's supposed to be Mahogany. The interior surfaces, even the hidden ones, are definately a Mahogany veneer that looks like modern Mahogany. The sides of the cabinet match that. The inside surfaces of the doors match it also. However, the front of the doors appear to be almost a different wood. I'd suspect that they put the wrong side out, but all of the other panels that are veneered have mahogany on both sides.

John

Nice job - that's a really good color match. Maybe just a tad more brown and less red, but I wouldn't worry about it especially if it's on a separate panel.

I've used Behlen water-base grain filler a few times. It's messy and there's a lot of rubbing and sanding, but the results are excellent - a glass-like surface.

How did the shellac work out as grain filler ? I've been meaning to try it out for a while since it seems less messy.

Maybe that odd veneer is from a different batch - or maybe it is a different species. That's one advantage of toner lacquer - it's easy to mix species and get the same color.

...
How did the shellac work out as grain filler ? I've been meaning to try it out for a while since it seems less messy.



It takes more coats than I'd prefer. I had cut mine pretty thin for another project. It dries fast though. If you're refinishing a project the shellac is supposed to stick to almost anything, even urethane. I've not tried that.

John

Has anyone had experience with J&J tubes? I noticed that the horizontal on my Sylvania was starting to drift out of alignment so I decided to check the tubes in that section. When I plugged the JJ ECC-82 into my tube tester one set of filaments lit up like a light bulb briefly. The other side was fine. I thought I made a mistake in the settings, but I doubled checked and also checked the voltage at the socket and everything was fine. It would also make sense that the problem I was having was due to this tube.

http://www.jj-electronic.com/pdf/ECC%2082.pdf They're made in the Slovak Republic.

They look really well made, but I'm leary of getting more as replacements.

John

That's just a 12AU7 isn't it ? I can send you a few if you need some.

Yes, it's just a 12AU7. I foolishly bought the gold plated version of the ECC-82 from AES thinking that it would be more reliable and have better controlled characteristics if I had to replace it in the future.

JJ doesn't list this version on their web site anymore, which is interesting. AES still carries it.

I'm pretty sure the light bulb effect was because of a heater-cathode short. I looked at the schematic of the Precision 10-12 and when you set it up for a particular tube the first state that it will be in is with the filament return selected and all other pins connected to filament supply. With a cathode-heater short, say in the middle of the filament, then it's like applying 6.3VAC to a 3VAC filament. The cathode that is connected to pin 3 is shorted to the heater, but there's no way I could prove that it didn't happen after the burn-out.

I'm going to check the ECC-82 that I have in the vertical section with a leakage checker first.

Thanks for the offer of the 12AU7s. I just bought four "Baldwin Sylvania" 12AU7s on ebay for less than I paid for a gold ECC-82.

John

The ECC-82 was working even with the shorted heater/cathode because the cathode of that section is at DC ground anyhow. *I meant to also say that the filament supply is isolated.* It just injected some hum, which I had noticed. There had been a very small slow weave of the dot pattern. It would reduce the feedback in the horizontal oscillator a little bit.

I put in a 12AU7 that I had taken out of the set. It's at the low end of the good scale, nearly in the weak when I test it. Using it I get insufficient horizontal width and fold-over on the right. I hope the ones I ordered are strong.

I was surprised that it performed so poorly with this tube so I did some more checking. I found one resistor out of tolerance by 20%. It's a 10% resistor. Probably shouldn't matter too much but I'll replace it. Another one is off by 20% and one is just the wrong value. It looks like someone replaced it using the schematic from the previous production change and not the current one for this chassis. This ends up shifting the grid bias on the Horizontal Discharge half of the 12AU7.

The 6BD5 horizontal output tube seems strong and I didn't find anything wrong in that section.

John

I decided that R151, 470K being high by 20% shouldn't be problem since they used a 2.2meg in the previous version. I was wrong about R152 being the wrong value installed, I misread the bridge number in the schematic. R155 is a bit high, but again shouldn't cause a major problem. I tried various 12AU7's and still had the folding on the right. I decided to take the JJ ECC-82 from the vertical section and try it expecting to have the horizontal back the way it was. No, changer other than improved width.

I then did the horizontal alignment. This was much easier than the first time since there was much less interaction between the adjustments. Everything behaved as it should. I ended up with a nice horizontal alignment. This makes me believe even more that the brand new ECC-82 that I had used originally, had a heater/cathode short to begin with.

If you want to read about how the alignment is done you can find it at:
Service Manual (https://www.msu.edu/~yurkon/Sylvania_bulletin_9-2.pdf)

It uses the following supplements:

Supplement-1 (https://www.msu.edu/~yurkon/Sylvania_9-2_Sup1.pdf)

Supplement-2 (https://www.msu.edu/~yurkon/Sylvania_9-2_Sup2.pdf)

I have chassis C15 and bridge B17.

While the effects are obvious, I don't understand why the charge peaking resistor R211 needs to be shorted in the first part of the adjustment, or what the ringing coil L60 does.

An oddity is the 20MFD electrolytic paralleling a fuse. It's C219 around F1. Any ideas on that would be appreciated.

John

I was still having a problem with focus on the right hand side of the raster. Jr_tech's suggestion made the most sense so even though I didn't see a ripple in the screen bias I added, I decided to check it again.

I foolishly decided to try a different 6BD5GT HOT at the same time. I didn't get a raster and no HV. I checked the fuses and F3 was blown so no -125V.

I checked the 6BD5 I put in and it was at 100% where a NOS tube should be 70%. I probably should have reduced the horizontal width before turning it on. F3 used to be 1/4amp but they upped it to 0.3amps. Probably still marginal. Replacing it and going back to the first 6BD5 didn't bring back the HV though. I did all the tests I can without removing the HV assembly from the bridge and everything looks o.k. Fortunately the HV RF transformer seems good. That would really be unobtainium.

Maybe the 6Y6 went bad just by coincidence. Except for taking out the fuse, I don't see why the 6BD5 would make the HV go away. The heater of the 6W4 is isolated so a short there shouldn't matter either.

The radio works so the +170 and +180 must be o.k. I'll have to swap the 6Y6 and if that doesn't work, then start troubleshooting.

John

** I forgot, there was something else I did differently too. I had left the TV in the radio position when I shut the AC off. It was still in this position when I turned the AC back on. The HV section still has +170 and -125 supplied to it when the radio is on, but the filament of the 6Y6 is off. Maybe the 6Y6 didn't like waking up this way. Guess I'll find out when I sub it. **

My dad had cut 1/4" off the bottom of the molding in front of the TV section to make room for the cedar boards to fit. You can see the cut in the first photo.

I carefully measured the radius of the bead and bought a beading bit for my router. Although it's obvious in the second photo, I didn't notice that the step isn't perpendicular to a tangent of the arc. I could still use the router bit to make a replacement molding, but I'd have to do it in two steps. First make the bead at the appropriate angle, then go back and make another cut to square up the step. The second cut would have to be precise.

It turns out that the molding goes up 1/2" under the top front trim so all I really have to do is remove the molding and slide it down to the bottom. The top will still be hidden by the trim.

Well, if I break the second molding removing it I at least have a cutter to try to make a replacement.

John

Well, the lack of HV turned out to be the 6Y6. I put in a new one and I got a solid 11KV. Maybe there's something to this cathode stripping theory after all. I hope not, I like to listen to the radio on this set and that biases the 6Y6 with the heater off.

With the higher HV the horizontal width is marginal. I have to turn the width control to the end. I tried the NOS 6BD5 that I thought killed the B- supply. I turned the width to minimum first. It gave me a raster, then as I turned the width up it would soon start to collapse. Eventually, even at a reduced width bad things started to happen. I wasn't sure if it was Barkhausen or breakdown. It caused static in the audio and looked scary enough that I immediately shut it off. The tube tests at 100% when it should test 70% if new.

I can improve the width by going to a 6BQ6. It's an easy change, but it would make it a bridge code B18 instead of B17. I'm not sure if I want the bridge to be different than the version stamped on it.

This and the 12AU7 are two bad tubes in one lot from AES. I can't blame them, but the next time I order any tubes I'll test them in circuit immediately upon receipt. I have a small stock of bottle shaped 6Y6's. I have two really good ones from eBay. Looks like I'll need to obtain a few more.

The focus is better, but when using a dot pattern it's clear that it's an astigmatism. I can correct it with a weak external magnet. The next time I have the CRT out I'll try degaussing the yoke support and play around more with the location of the focus magnet. If that doesn't work I guess I'll resort to mounting a weak magnet.

The photo is the plate of the horizontal discharge 12AU7 tube. The service manual shows a rounded sawtooth and it doesn't have the dip between the teeth that mine shows. Is this a problem?

John

In regards to the scope trace of the horizontal discharge tube plate, it looks like the trace I show is correct and the service manual is wrong. Later sets using the same exact circuit show traces like the one that I photographed.

Also, C219 that is shown paralleling fuse F1 is partially explained by Wallace's Telaides. It seems to help the fuse respond only to the average DC current and not the large peaks from the horizontal sweep. Also, they moved one end from the +180 to the +170 to help the horizontal oscillator start more reliably. I didn't think a fuse had a significant impedance, but it must if this helps.:dunno:

John

John,

That Sylvania of yours is a very curious beast. Sylvania definitely did their own thing, design-wise. I have several 10" and larger sets that use RF high voltage power supplies, and have always enjoyed them. I have never seen any other 40s vintage TV with a large capacitor across a fuse. Seems curious, probably not the best design. But a really interesting set from a technical point of view. Thanks for posting the service data.

John,

That Sylvania of yours is a very curious beast. Sylvania definitely did their own thing, design-wise. I have several 10" and larger sets that use RF high voltage power supplies, and have always enjoyed them. I have never seen any other 40s vintage TV with a large capacitor across a fuse. Seems curious, probably not the best design. But a really interesting set from a technical point of view. Thanks for posting the service data.

Thanks John. To me the design seems straightforward because it's the first TV I was exposed to as a kid. I participated when my Dad did repairs, or when Gus Wall, our TV repair guy would make a home visit. And I actually enjoyed the smell of selenium rectifiers. Well, I admit the large cap across a fuse is strange..

From looking at old texts, data-sheets that I looked at nearly 50 years ago, and old magazines, I think Colonial Radio cut and pasted patented circuits and did some of their own weird stuff like the paralleled 5U4 and 7X6. The horizontal circuit seems to be from RCA. The RF HV, I'm pretty sure, is from Spellman who manufactured HV supplies for TV's. I think that's where they got their start.

I decided to try to understand why a 6BD5 that tested so good, performed so poorly. I guess if something seems to good to be true, it is.

The tube is definately NOS. The getter looks good at first glance, nice and shiny, but looks horrible when you shine light through it. I also noticed a slight haze on the envelope around the plate area.

So, I put it back on the tube tester and turned out the lights. When I did the dynamic test there was a blue glowing haze between the plate and cathode. The tube is gassy. It acts like it has higher emission, but is really gassy.

The supplier only gives a 10 day warranty period and I tend to be too trusting. I'm dissappointed that I had two bad tubes in one order. I've had better luck with eBay. I'll still use them but I'll test as soon as I receive any tubes and I have a better idea of what to look for now. Hopefully I won't fool myself like I did with the gassy tube.

I have a Senecore LC3 leakage tester which works great for the tubes it handles, but it doesn't do the 6BD5 or 6Y6. The Precision 10-12 will find shorts, but doesn't do a sensitive leak test. But I have seen 1B3's glow blue from gas with it and now the 6BD5.

I'm tempted to try a 6AU6, would that make a good substitute for a 6BD5?

John

"I'm tempted to try a 6AU6, would that make a good substitute for a 6BD5?"

huh?:saywhat:

jr

Oh, I get it... My substitution book sez 6AU5 6AV5 6FW5 if not series filament circuit.:yes:

"I'm tempted to try a 6AU6, would that make a good substitute for a 6BD5?"

huh?:saywhat:

jr

Oh, I get it... My substitution book sez 6AU5 6AV5 6FW5 if not series filament circuit.:yes:

Oops! Typo. The filaments are all parallel so there's no problem there.

Actually I wasn't wearing my glasses and a 5 looks alot like a 6 when it's smeared out... Thanks for pointing that out.

John

The 12LP4 that Scotty has rebuilt with a rebuilt gun came today. I installed it and it works great! I still have to figure out the focus issue though.

I might have to go back to the 10MP4 just to make sure that something else didn't change or fail coincidentally.

John

The 12LP4 that Scotty has rebuilt with a rebuilt gun came today. I installed it and it works great! I still have to figure out the focus issue though.

I might have to go back to the 10MP4 just to make sure that something else didn't change or fail coincidentally.

John

Awesome - I'm glad someone is still rebuilding CRTs!

Still trying to figure out the focus issue on the right side. I tried rotating the focalizer 180 degs but that had no effect. I thought that if it was at fault that the problem would switch to the left side.

I scoped all the voltages including the HV. They're stable. Only the HV shows any structure and I don't believe it's enough to cause the problem.

All the photos have a vertical scale sensitivity of about 60V/div. It was AC coupled using a 20KVDC, max pulse 40KV scope probe.

In the first photo you see the pips correspond to the horizontal retrace. The rest of the variation is due to the video signal. The second photo has the time base set to view the vertical sweep period and the fuzz is the horizontal retrace pips. In the last photo I turned the brightness down and all you see are the horizontal pips.

I think the horizontal pips are capacitively coupled from the windings on the yoke to the aquadaq, which is capacitively coupled to the dag on the inside connected to the HV. The horizontal windings are closest to the neck of the CRT.

The HV was about 11KV during this test. The variation appears to be about 50 volts PP. I doubt that 50 volts would affect the focus much.

The resistor in series with the HV supply is about 470K. So, 50 volts means about 100 micro-amps, which is probably reasonable with the brightness set high.

I looked at the old test pattern photos I took with the 10MP4 and I see that it has the same problem, just to a lesser degree. I'm starting to think that the problem is with the yoke.

I'm going to ring test the yoke and perhaps swap the horizontal leads to see if the focus issue moves to the other side of the screen or stays put.

John

"I'm going to ring test the yoke and perhaps swap the horizontal leads to see if the focus issue moves to the other side of the screen or stays put."

That experiment should be interesting!

"20KVDC, max pulse 40KV scope probe"

6015A?

jr

"I'm going to ring test the yoke and perhaps swap the horizontal leads to see if the focus issue moves to the other side of the screen or stays put."

That experiment should be interesting!

"20KVDC, max pulse 40KV scope probe"

6015A?

jr

Yes, but not mine. I borrowed it.

John

I ring tested the yoke with a Sencore LC101. If the yoke is good it's supposed to give 10 rings or more. I got 9 max. Not definitive.

The DC resistance is supposed to be 36 ohms. I measured 47 ohms. The yoke is a bit different in that the horizontal windings are in parallel. This would mean that each coil should be 72 ohms. If I assume the difference is due to one coil, then it would have a resistance of about 135 ohms. Quite a bit different.

I swapped the horizontal leads and while the raster reversed, the focus problem remained on the same side. This, along with trying to rotate the focus magnet and moving to different positions has no effect on the problem leads me to believe that the yoke has a problem.

Another clue is that it appears that someone replaced on of the horizontal leads with HV wire. It has a polyethylene core and a plastic jacket. All the other leads are fabric coated.

https://www.msu.edu/~yurkon/Photos/young_einstein.jpg
Normal

https://www.msu.edu/~yurkon/Photos/Hleadsswapped.jpg
Reversed

The ringing is probably due to the long jumpers I used to connect the yoke.

Notice that the keystoning is the same for both. If it was a supply issue it should be reversed when I reversed the leads.

It looks like I need to search for a yoke.

I would need a Sylvania 100-0001 or a 100-0002 and a horizontal choke 241-0002. The second version has a center tapped yoke instead of parallel windings and thus needs a center-tapped choke. I'd call it a transformer, but they call it a choke.

The Merit numbers would be MD-13 for the yoke and C-2980 for the choke.

If anyone can provide Thordarson or other cross reference numbers that would be great. The actual parts would be even better! ;)

John

If you rotate the yoke 90 or 180 degrees does the area of poor focus follow the mechanical rotation of the yoke? If it still stays on the right hand side of the tube, perhaps some steel part near the neck of the CRT is magnetized ?

jr

I can probably only rotate the yoke over a +/-15degree angle. But that's probably enough to do the test you suggest.

I don't think it's a magnetized part of the chassis. The point at which the focus gets bad follows a vertical line. I wouldn't expect it to follow a straight line line if it's the chassis.

It's a good test though, if the bad focus rotates too, then it has to be the yoke.

John

I have a Sylvania yoke that is similar to the one in the set. I just did a ring test on it and got 25 rings. Quite a bit more than the one in the set.

Sencore says to make a shorted copper loop and place it around the yoke windings. If the number of rings doesn't change by a lot, then there is probably a shorted turn.

I'll have to try that along with rotating the yoke over its limits.

But, not tonight...

John

I finally scored a hit with Moyer's. They have a RAM yoke that will replace either the 100-0001 or 100-0002 Sylvania yoke. I don't think that there are many of these around so it won't hurt to have one on hand even if it turns out that the yoke is o.k.

John

Sorry I don't have time to read this lengthy (and great) thread, but that looks like an h-linearity problem to me. See how it's all stretched out on the right hand side in the second pic?

Sorry I don't have time to read this lengthy (and great) thread, but that looks like an h-linearity problem to me. See how it's all stretched out on the right hand side in the second pic?

That's true, but is only due to the temporary connection by the use of jumper leads. It's not part of the focus problem that I'm concerned with.

John

I tried rotating the yoke over the limits of it's travel as suggested by jr_tech. I used a dot pattern to judge whether the focus problem followed the rotation or not. It follows the yoke.

I'm getting more and more convinced that the problem lies with the yoke. I should find out soon, when the RAM yoke arrives.

John

I received the RAM replacement yoke today. I tried ring testing the horizontal and saw 33 rings as opposed to the 9 rings I saw with the original yoke.

I don't think I'll get a chance to install it this weekend. The core is loose on this yoke also and I'll need to fix it in position before I install it.

John

Hope the new one fixes the problem, you're so close to having a very nice picture!

I made a couple of attempts at making rosettes. The one on the left was done with a clear epoxy that is close to mahogany in color. I did spray it with brown mahogany lacquer.

The one on the right is made with a white paste epoxy. I think I'll try dying the epoxy to the right color, then give it a coat. Although it does kind of match the aging of the cabinet as is.

I need to trim the rosettes a bit to remove the excess epoxy.

The photo on the right shows the rosettes before coating.

John

I finally got around to swapping the yoke. Guess what, it was the yoke that was causing the focus issue! :banana:

I'll post some photos as soon as I get it finalized. In spite of being careful I managed to swap the two horizontal leads. I left them long in case I did something stupid like that. There's a bit of ringing that I hope clears up when I dress the leads.

The yoke that was in the set is the wrong yoke. It was a 100-0002 and the manual says that you cannot use it with an output choke that isn't center tapped without danger of breakdown in the yoke. That must be what happened to it. The manual warns that servicemen have been replacing the 100-0001 with the 100-0002 when they shouldn't.

The yoke I put in though is made just like the 100-0002. Moyer said that RAM says it can be used for either yoke. It came wired as though it was a 100-0001, but internally it's like the -0002.

Does anyone have a RAM catalog? I'd be interested in knowing what it says about a Y70F25 yoke. It's to replace a 100-0001 yoke in a 1-108 sylvania chassis.

I'd feel better about using it if I could find a center tapped choke to go along with it. Can anyone tell me cross reference numbers for a 241-0002 choke for this set? I've yet to figure out why they call it a choke instead of a transformer. :scratch2:

John

John,

Thats fantastic! Way to go. You may find the ringing is better when you swap the yoke leads, as often the yoke has a balancing capacitor across one of the two horizontal windings.

The Y10F25 yoke is speced at 25mH (H), 50mH (V), 27 ohms (H) and 60ohms (v). RAM does not list a replacement for the 241-0002 (flyback transformer, not a choke)

Thordarson, Stancor and Merit do not list a replacement. Must be an oddball flyback...?

The Thordarson cross ref. lists the 1-108 chassis as using a 113-0010 flyback, with a HVO-50 replacement. Is this a mistake in the Thordarson listing?

John,

Thats fantastic! Way to go. You may find the ringing is better when you swap the yoke leads, as often the yoke has a balancing capacitor across one of the two horizontal windings.

The Y10F25 yoke is speced at 25mH (H), 50mH (V), 27 ohms (H) and 60ohms (v). RAM does not list a replacement for the 241-0002 (flyback transformer, not a choke)

Thordarson, Stancor and Merit do not list a replacement. Must be an oddball flyback...?

The Thordarson cross ref. lists the 1-108 chassis as using a 113-0010 flyback, with a HVO-50 replacement. Is this a mistake in the Thordarson listing?

I was wondering about whether the balancing capacitor would do that, but it goes against my grain to think that a one-port passive network would behave that way. There must be enough stray capacitance to make another connection, turning it into a two-port. It does seem to behave as you said though. At least the original one did so I hope this one does too.

Thordarson didn't exactly make a mistake. The RF HV supplied sets don't fit neatly into the charts of Thordarson, RAM, and Merit. The 113-0010 is the RF HV transformer and is listed for the Horizontal output in the Merit catalogue also, even though that's not what it is.

I wouldn't call the 241-0002 a flyback because it doesn't use the retrace (flyback) to generate the HV. It looks just like a filament or audio transformer. All four of the manuals that I have for this set call it a choke, including the SAMS. I assuming that they have a reason to call it that. It hurts my head to think about that part of the schematic. :drool:

If you want to peruse the service manual you can see it at:
https://www.msu.edu/~yurkon/Sylvania_9-2_Sup1.pdf

Thanks for pointing out the 113-0010 being called a flyback. I now have cross-reference numbers to search for a spare. :thmbsp:

John

John, I am afraid I am a poor student. I had forgotten your Sylvania was one of those very interesting RF HV supply sets, and would use s separate transformer (choke?) to drive the horizontal coils. I also note on the schematic the yoke coils are wired in parallel, so my supposition about the balancing capacitor is probably not valid. But hopefully when you reverse the leads on the yoke, your ringing issues will get better.

Good thing you don't have troubles with the RF HV coil, as some of these don't have a replacement.

I made a couple of attempts at making rosettes. The one on the left was done with a clear epoxy that is close to mahogany in color. I did spray it with brown mahogany lacquer.

The one on the right is made with a white paste epoxy. I think I'll try dying the epoxy to the right color, then give it a coat. Although it does kind of match the aging of the cabinet as is.

I need to trim the rosettes a bit to remove the excess epoxy.

The photo on the right shows the rosettes before coating.

John

Any thought of making a wood one? If you could make a study enough die, (maybe with jb weld?) you could probably make one the same way the originals were made. Maybe cut a circular piece of mahogany, soak it in water for a while, and force your die over it, maybe in a vice, and let it sit until the wood dries?

Any thought of making a wood one? If you could make a study enough die, (maybe with jb weld?) you could probably make one the same way the originals were made. Maybe cut a circular piece of mahogany, soak it in water for a while, and force your die over it, maybe in a vice, and let it sit until the wood dries?

That would be cool! I think I might try it.

John

John, I am afraid I am a poor student. I had forgotten your Sylvania was one of those very interesting RF HV supply sets, and would use s separate transformer (choke?) to drive the horizontal coils. I also note on the schematic the yoke coils are wired in parallel, so my supposition about the balancing capacitor is probably not valid. But hopefully when you reverse the leads on the yoke, your ringing issues will get better.

Good thing you don't have troubles with the RF HV coil, as some of these don't have a replacement.

The yoke that was in the set, and the replacement, are both made as you described with the coils in series and a capacitor across one coil. The 100-0002 yoke that is in the set was meant to be used in a center-tapped mode. The schematic shows the 100-0001 yoke where the windings are in parallel. That's the yoke that should have been in the set.

So, your comments really do apply.

I wonder why there are replacements for all of the other transformers and coils, but not the horizontal output thing?

John

John, if reversing the yoke leads does not work, I wonder if you could try rearranging the yoke to operate in parallel, without the balancing cap? How does the inductance of the replacement yoke compare with the original? What Sams Photofact is your set in?

These RF HV supply sets for the 10" and 12" CRTs were oddball sets even in their day, and I suspect the Thordarson/Merits/Stancors of the day did not consider it worthwhile to make these low volume parts.

John, if reversing the yoke leads does not work, I wonder if you could try rearranging the yoke to operate in parallel, without the balancing cap? How does the inductance of the replacement yoke compare with the original? What Sams Photofact is your set in?

These RF HV supply sets for the 10" and 12" CRTs were oddball sets even in their day, and I suspect the Thordarson/Merits/Stancors of the day did not consider it worthwhile to make these low volume parts.

The folder is number 11, set 96. I find the SAMS more difficult to read than the Sylvania or Wallace schematics.

The inductance of the RAM yoke is the same as the Sylvania. If I were to rewire the coils in parallel the resulting inductance would be somewhere between 1/4 to 1/2 the original inductance, depending on how much mutual inductance there is between the two.

I'm doing laundry tonight and when I do laundry I don't have access to the trap door to my basement so I won't get to try it tonight.

Roger Dreyfoos sent me some info from a RAM guide to yokes that is pretty interesting. It talks about residuals fields in some that need to be eliminated. I thought that was my problem, but now I think it's just a bad yoke to begin with, but no shorts.

It has an iron wire winding to form the core, that likely accounts for the low ring test. I don't think there's a short because both half coils test the same for inductance and number of rings. It probably doesn't shield well against the focus magnet which causes a rotation in the raster.

The yoke also appears to be deformed, I'm not sure why that is, but it is also off axis from the housing. The off axis problem is just the way it was assembled.

It also appears that it is not cosine wound, which doesn't help the focus either.

I'm still going to check it out with a hall probe, but using the digital compass on my watch suggests that the residual field is less than the earth's field. I don't think a residual field is the problem. If it turns out to be stronger than that, I might try degaussing it.

John

This is getting to be more involved than I expected.

I checked for residual magnetism in the yoke. The earth's field in Michigan should be about 0.57 Gauss. The field along any axis in the yoke was 0.5 Gauss or less so it doesn't appear to be magnetized. At least not enough to cause any problems.

The first photo shows the rear of the yoke. You can see the bottom h-coil is distorted. The second photo shows that it doesn't appear to be cosine wound. The third photo shows the ends of the coils not being perpendicular to the axix. I think these all add up to the bad focus issue.

If you look through the mounting slot you can see the iron wire that forms the core.

I shortened the leads on the yoke and corrected the reversed horizontal lead connection. The ringing is terrible.

After getting the right image by swapping the leads, the blue lead was not connected to the hot side as both the schematic says and the data sheets indicate. The horizontal output choke appears to at least had one lead lengthened. I don't think it's possible for them to have reversed the output leads and have it work at all.

As John Folsom mentioned, the coil that has the capacitor across it should be on the hot side, which it isn't now that I have the right image. I'll have to move it to the hot side and see how well it works.

The data sheet with the RAM yoke says that when they supply the network with the yoke it's not connected. In this yoke it was already connected. They also give instructions for balancing the yoke if there is still ringing after properly connecting the supplied network. If connecting the capacitor to the other coil half doesn't eliminate all the ringing I'll have to build their little "X" checker device. Just a variable resistor and capacitor in series.

I don't want to run the set while it's in this condition, so I'll take photos once I get it working better.

In spite of the ringing, the focus problem is still gone.

The yoke appears to have been made by Chicago. It looks just like their TY-1 yoke.

John

You can see the Chicago TY-1 here: http://www.bunkerofdoom.com/xfm/CHICAGO1954/004.jpg

and the similarity to the Sylvania 100-0002 is very strong.

The data is here: http://www.bunkerofdoom.com/xfm/CHICAGO1954/003.jpg

and the TY-1 is not cosine wound. It has an iron wire core just like the Sylvania. Not too surprising that focus was so touchy. Especially if they stretched the design to go from 53 degrees to 70 degrees.

John

I moved the balancing capacitor from its original position to the hot side of the yoke. I didn't take any before pictures because the ringing was so severe I was afraid it might damage something.

I haven't aligned the horizontal section or do any serious adjustment of the vertical. I was mainly interested in seeing whether the ringing would be reduced and if the focus would be good. The focus looks good, there is still a little bit of ringing.

The balancing cap in the original yoke was 47pf and the one in the RAM replacement is 68pf. I'll probably use a variable cap first to see what value works best.

Then I need to shim the yoke. For some reason it tilts down a little when it's mounted in the saddle.

Then I'll align the horizontal. That will take care of the curvature and reduce the flagging. There was always some flagging unless I was receiving an over the air broadcast. No chance of that now. There may be a minor problem in the sync separator.

John

Looking good! :banana::banana::banana::banana:

Wow! That was a long uphill battle, but it really shows that persistence does pay off! :yes:

jr

Looking good indeed:thmbsp:
What are you using to generate that test pattern ? It's fantastic :yes:

Looking good indeed:thmbsp:
What are you using to generate that test pattern ? It's fantastic :yes:

It's a reference disk for my Laserdisc player.

John

John, That now looks really good. Persistence pays off!

Why would you have to shim the yoke? Can't you slide it up snug against the bell of the CRT?
Your picture is really looking good!

Why would you have to shim the yoke? Can't you slide it up snug against the bell of the CRT?
Your picture is really looking good!

The yoke sits in a half tube that has a slot. A thumbscrew goes through the slot to allow you to rotate the yoke. The nut that the thumbscrew goes into can slide along the length of the yoke. Once in position you're supposed to tighten the thumbscrew. If you don't it doesn't stay in position. The problem is that when I tighten the thumbscrew the front of the yoke is too low and the rear is just a tad too high.

http://www.videokarma.org/attachment.php?attachmentid=165594&d=1258246674

The half tube in the early sets had slots to allow you to adjust it's position. In later production they just spot welded it into place. I guess the replacement yoke doesn't match the physical shape of the original yokes well enough. The slots are still there. I could drill out the spot welds and add the adjustment, but I rather just shim the yoke between it and the half tube.


John

I read in an RCA TV servicing guide that the trapezoidal raster that I had would be caused by a problem with the vertical portion of the yoke. I don't understand that, I really thought it would be the horizontal, but decided to check it out.

In order to ring test the sections properly I have to remove the core. I started to do that, but after removing the damping resistors for the vertical windings I decided to check them. They are supposed to be 560 ohms each. They are 680 ohms and 725 ohms. I think that's enough to cause a problem and I should have checked that before swapping the yokes.

I'm trying to decide whether to replace the resistors and reassemble the yoke, or to continue the testing. I'd have to unwind a lot of iron wire and rewind it carefully later. To check the coils individually it's necessary to reduce the mutual inductance by removing the core. However, the vertical and horizontal shouldn't have much coupling. I ring tested both and got 9 rings each. There might not be a short and the real problem could have been due to the bad damping resistors.

In either case, I'm not going to put it back in this set since Sylvania says that this model yoke shouldn't be used with the horizontal choke that is in the set because of danger of breakdown.

John

I wonder if you could use an Eico 944 Yoke tester on it ? Supposedly they can detect a single short.

I wonder if you could use an Eico 944 Yoke tester on it ? Supposedly they can detect a single short.

It would be interesting to try, but I think they'd give the same result. I took a quick look at the manual for the Eico. Both the Eico and the Sencore LC101 test the yoke by measuring the absorbed energy, though by different means, and are sensitive to a 1 turn short. The Sencore does it by forming a resonant tank circuit and pinging it. It then counts the number of oscillations to decay a certain fraction.

The problem is that with an iron wire core the Q is low and the energy absorbed is higher. The results I get with the Sencore are right at the border line. The Eico manual also indicates that you can run into this problem, and in that case you want to compare the reading with an identical yoke. The replacement yoke I have isn't identical, it has a powdered iron or ferrite core which gives you a higher Q.

If I remove the iron wire, then either unit should give me an unambiguous result since the Q should be quite high.

John

I finally got around to doing more work on the cabinet. It's difficult for me since I expect everything to be square and all measurements to be a multiple of a rational number.

I replace the missing support rails and made a new base for the chassis. The square hole on the left is for the speaker cable. The oblong hole on the right is for the AM antenna wire. The small square opening is to access the adjustments that don't need frequent access. I was forbidden to touch these as a kid.

There was another hole that could only have been used to adjust the tension on the CRT strap. I don't understand why they put it there since you have to remove the chassis to remove the CRT.

Maybe they wanted to be able to re-tension the strap before shipment, after the rubber pads conformed, or perhaps make it easy for the installer to raise the base end back up if it got shaken down during shipping.

John

Shit John,

If you keep doing work that looks this good, my stuff is going to start looking shabby in comparison :yes:

Bob

I made a mount for the speaker. I suppose there's a technical name for it.

I attached a grille cloth. The proper grill cloth would have had a similar pattern, but much darker brown. Almost charcoal grey with silver thread running through it.

There seems to be a stain on the cloth. I noticed it when I went to iron it. I think it's oil or sweat. When I placed the first order for the cloth they sent me a 1'x2' piece when I ordered and paid for a 2'x2' piece. I think next time I'll order it from the place that specializes in vintage grille cloth. I suspect they put more care into it.

There's some stain, water based I hope, that I have to clean off of the finish. This was from when my dad converted the cabinet to a linen cabinet and lined it with cedar. He had to add some rails and stained them to match. There's a few holes to fill also.

I have to make some round corner molding to finish the installation of the speaker.

John

You may want to, if you haven't already, paint the light tan colored plywood mount for the speaker black, so it isn't visible thru the grill cloth.
http://www.videokarma.org/attachment.php?attachmentid=167580&d=1277878296
http://www.videokarma.org/attachment.php?attachmentid=167581&d=1277878296

Good idea, but I already glued the speaker cloth on. It won't show up much under normal lighting. It's pretty much shaded since it's recessed from the front by about 13". A camera with a flash always makes it look worse.

If I end up redoing it I'll paint it as you suggested. I'm not real happy with how I distorted the fabric. Next time if I use a lightweight fabric I'll make up a clamp to stretch it rather than trying to use gorilla tape.

Oddly enough gorilla tape didn't want to stick to the fabric.

John

Odd, the area that looks like it has a stain doesn't look that way anymore. I used steam to press it but I would have thought that would evaporate quickly.

John

Well, I guess the stains are still there, they just don't show up except when you take a photo. The same with the speaker cutout. I should have painted it a dark color, but it doesn't show up under diffuse lighting. I said the speaker was recessed 13". Not sure what I was drinking, it's more like 5-1/2".

I made corner molding out of mahogany using a 1/4" round-over bit with a router and table saw. I still need to varnish them and nail them in.

John

I put a finish on the molding and installed it. That's a little difficult since it's only 1/4" wide. I wasn't able to come up with a filler for the brads that match the finish very well.

The color of the grille cloth seems too light. In looking at the photo on the front of the Sams I'm not sure it was a diamond pattern.

I remember it being nearly black, my brother says it was dark brown with silver running though it.

AES has a black and a brown basket weave pattern for guitars that looks pretty close. I'll order some samples and see if I like it. If I do, I'll probably change the grille cloth.

Looks like my work was kind of clumsy on this one.
http://www.videokarma.org/attachment.php?attachmentid=167604&d=1278218649



http://www.videokarma.org/attachment.php?attachmentid=167605&d=1278218649


John

I finally finished up the panel. I started by laminating ribbon cut mahogany paper backed veneer on to plywood. I veneered both sides to prevent it from bowing later. I used Heat Lock glue.

https://www.msu.edu/~yurkon/VK/ribbon_mahogany.jpg

I then made a paper template.

https://www.msu.edu/~yurkon/VK/template.jpg

After transferring the template I cut out the panel.

https://www.msu.edu/~yurkon/VK/panel_cut.jpg

Then I checked the fit.

https://www.msu.edu/~yurkon/VK/it_fits.jpg

I then filled the grain by padding on six coats of orange shellac. Sanding it down to the wood with 180 grit sandpaper. Then repeated, but just sanding down almost to the wood. 180 grit is too coarse. I used it after reading a procedure on a woodworking site. I ended up using 600 grit for sanding between coats of Lacquer. I used Mohawk Classic Brown Mahogany.

The front after apply several coats of the toner lacquer and a couple of coats of clear satin.

https://www.msu.edu/~yurkon/VK/panel_lacquered.jpg

https://www.msu.edu/~yurkon/VK/panel_satin.jpg

And the back with clips installed.

https://www.msu.edu/~yurkon/VK/panel_back.jpg

In order to screw it in with wood screws as it was originally done I had to make a fixture for my drill press to angle the screws 30 degrees from the normal. I glued on cork so that it wouldn't affect the finish. I couldn't just free hand it because the panel sits behind strips that are only 3/16" thick and you don't want to risk having the screw hole show up.

It was either this or make a drill guide to hold in place inside of the cabinet and use a hand drill.

The fixture:

https://www.msu.edu/~yurkon/VK/30_deg_fix.jpg

Here's the final product. I'll have to take some photos of it working. The bezel is NOS courtesy of rdreyfoos. It has a little shop rash on one corner, but I'm reluctant to try to repaint it at this time.

https://www.msu.edu/~yurkon/VK/tv_panel_fin.jpg

As I mentioned previously, I don't want to refinish the rest of the cabinet for sentimental reasons so I had to try to match the finish.

John

Wow!! Fantastic job :banana:

How did you cut out the panel ? It looks very clean and crisp.
I'm a little surprised how red that toner turned out. I'll keep that in mind for future projects.

Wow!! Fantastic job :banana:

How did you cut out the panel ? It looks very clean and crisp.
I'm a little surprised how red that toner turned out. I'll keep that in mind for future projects.

The round holes were drilled with Forstner bits. The large opening and the square hole were cut with a scroll saw. I then made a jig with a rectangular opening and used a laminate trimmer in a router to clean up the square hole.

I then used the router on the table saw's router table to clean up the straight sections of the CRT bezel hole. I had to touch up a couple of places on the curved sections by hand with the router.

It did come out pretty red, but the red was accentuated in the outside photo because the sun was setting on the horizon.

John

Here are a couple of photos with it working. With just the room light the CRT shows up too bright. With a drop light it's kind of washed out. Guess I'll have to do the room light, no room light, Photoshop trick if I want a good photo.

I need to rotate the yoke a bit. Seems to have moved while carrying it out of the dungeon. I also didn't notice that I needed to center the horizontal before taking the photo. That's been fixed now.

It had good bass before mounting the speaker in the cabinet. Now it seems a bit excessive.

John

WOW! looking good! What an incredible project! :thmbsp:

It is great to restore a set like this that is remembered from childhood, even better if the set, or in this case a major part of the set is the same one that you enjoyed as a kid. :yes:

jr

John, that set looks great. For me, the hardest thin is trying to take a good photo of an operating TV. And trying to get the exposure correct for cabinet and CRT is mostly impossible. :-)

It helps if you have a camera that lets you control the aperture and shutter. I use a Pentax K200D for all my photos, but it also helps to shoot in normal room light with the brightness turned down a little.

It helps if you have a camera that lets you control the aperture and shutter. I use a Pentax K200D for all my photos, but it also helps to shoot in normal room light with the brightness turned down a little.

Actually I have a Canon Digital Rebel and I shot the images at 1/8 sec to make sure I had full frames. I tried turning the brightness down until it was nearly invisible, but the raster was still too bright in the photo with normal room light. Maybe I should try it in the daytime in case natural light would help.

John

That picture looks excellent - very bright and clear :yes: Is that a rebuilt CRT ?

Photographing sets is a pain. The best results I've gotten have used daylight. I believe Eric photo-shopped a picture of his last restoration and it looked great.

That picture looks excellent - very bright and clear :yes: Is that a rebuilt CRT ?

Photographing sets is a pain. The best results I've gotten have used daylight. I believe Eric photo-shopped a picture of his last restoration and it looked great.

It's a 12LP4A that Scotty rebuilt for me. I had to add screen bias for it to work. He just finished rebuilding the 12VP4 for me. I'll have to try it when it gets here. I'm not sure if I'll use the 12VP4 for originality or stick with the 12LP4 and use the 12VP4 in the set it came with.

Now I have a very good 10MP4 sitting around. Guess I'll consider it a collector's item.

John

Actually I have a Canon Digital Rebel and I shot the images at 1/8 sec to make sure I had full frames. I tried turning the brightness down until it was nearly invisible, but the raster was still too bright in the photo with normal room light.

Did you also stop down the aperture? I shoot in aperture priority mode almost exclusively, so I can control how much light gets in. It can also help if you use the AE lock function (if equipped), or simply meter the shot on a different object before shooting. If you meter on the screen the rest of the frame will be dark, if you meter just below the screen the brightness of the sceen will wash out the frame. You're looking for something in between.

It can help if you put the camera into auto mode, look through the viewfinder, and see what it's using for settings on and off screen. For example if it gives you 1/8 sec@f/8 on the screen and 1/2 sec@f/2.4 off screen, try manually setting it for 1/4 sec@f/4 and see what happens. Play with it, eventually you'll get it right. here's a hint: backlighting the shot helps a lot.

Wonderful job John! The image quality on that set is fantastic. I would be happy if some of my sets look half that good.

BTW, I got won the Veeco calibrated leak for only $52. I hope there is still some helium in it :-) Folsom arrives on Saturday and then we start playing around to see if we can get the 925-40 to opperate.

Bob,
What is a " 925-40 "?
Leaks last what 10-20 years, plenty of helium in the quartz XTAL.
We send ours off once a year and they always come back within calibration.
Seems counterintuitive but, leave the valve open before and during the whole test or the value stamped on the leak won't be accurate.:banana:

Terrific image on that TV. You will enjoy watching it.

Taking screen photos drives me insane. I have taken thousand of shots -- literally -- in attempts to get a true image of what the TV really looks like playing in normal room light. If the rest of the scene looks normal, the screen is always overexposed.

The only solution for me is to take two photos as you say, with the camera on a tripod. First photo with room lights up and TV turned off. Second photo with room lights lower (not completely dark) and TV turned on. For the "turned on" photos, I take a few with the TV at different brightness/contrast settings, then pick the best one later. Once you have two that look good separately, copying & pasting the screen from one to the other does the trick.

Backlighting, or indirect lighting in general, work better than a single strong source.

Glare is an issue if the TV has a flat safety glass. In some cases, I've had to use two black dropcloths to eliminate glare. One spread on the floor in front of the TV and the other pinned to the wall behind the camera. Even then, you may need to pin a black towel around the tripod legs to keep them from showing up as a reflection.

Phil

I missed this one! Guess I shouldn't always rely on Eric to find sets for us. :D

http://columbus.iclassifieds.com/droid_item.php?t=forsale&c=antiques&i=117233274

It looks like the cabinet is in good condition. It's missing both rosettes like mine. It was listed a couple of months ago. Columbus isn't that far.

John

Is that the same model as yours ?

Is that the same model as yours ?

Yes. It's the same model as the one I've been recreating by using the 1-128 cabinet that my family still had and taking the 1-108 chassis from the 1-076 console and reconfiguring it to use the 12VP4 instead of the 10MP4. Fortunately the chassis are identical and just the CRT mounting is a little different.

I wish I could see a photo of the back of the one that was in Columbus so I could find out what the back cover looks like and where the AM antenna was wound.

John