Sylvania 1-076 arrived!
 

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

And I thought CRTs were dangerous!
 

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...

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 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 :)

Tubes
 

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.

I should have thought of that! Thanks!

John

10MP4 test
 

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

CRT removed
 

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

Electrolytic relocation
 

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

Some progress
 

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

Chassis Photos
 

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

Coffee Can HV
 

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

RF HV and Bridge recap photos
 

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

Bad Horizontal Center pot
 

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

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

Smoke test
 

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

First Picture
 

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...

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

Found the problem
 

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

Video IF
 

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

John

Video IF repair
 

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

IF rewinding
 

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