Thanks to RCA2000 I now have a model 1-125 12-1/2" table top Sylvania. Guess Sylvania includes the OD of the CRT in their sizing. :scratch2:

Jack was kind enough to deliver it to the ETF and Bob Dobush was kind enough to transport it to his house. I attended my dad's 100th birthday in Chardon, OH this weekend and stopped by Wellington to pick it up on my way back to Michigan. My brother is on the left in the photo and my dad's brother is on the right. Of course my dad is in the center.

The mahogany cabinet is in pretty good shape. I might try something like restor-a-finish. Or, just a good cleaning and waxing.

The set seems to have been in a very damp environment at some point in its life. The tube pins are quite corroded and there is rust on many parts.

The HV RF transformer seems to be good. I was afraid that it was damaged. The lead that goes to the anode cap of the 1B3 has been re-worked and appears to have been pulled loose and is just hanging by the secondary winding wire. The 6Y6's key was broken off. It looks like the HV section may have taken a hit and the 1B3 possibly broken yanking on that wire. Of course this is just a guess since the 1B3 isn't there. I do measure the proper resistance for the secondary so I'm happy. Someone has worked on this section in the past because all of the color coded leads to the transformer were replaced with yellow PVC wire.

The 12VP4 has marks on the aquadag that would have come from being in a CRT box. That will make it easy to remove. They glued the CRT's in when installed at the factory. They didn't ship the CRTs separately so this might be a replacement CRT. This CRT isn't covered by testers so I was going to set up a grid cutoff test using an external HV supply with a CRT tester like I did with the 10MP4. However, at this point I think I'll just pop it into my other Sylvania and see if it works. I fear that I'm too late to send it to Scotty if it needs rebuilding.

The bezel has some crazing. The crazing follows the flow of the injection molding.

This set will make it easier for me to make the front panel for the cabinet I'm restoring for the 1-128. I can use it as a template.

This set has the first chassis revision released after the initial design. That eliminates most of the serious issues with the original design. There are a number of revisions after this, but this one should be fine.

I need to get a can made to cover the HV section though. It makes horrendous RFI otherwise. Anyone know where I can get a custom can made?

John

I was surprised to find that the knobs on this set had the white crud growing on them. My other Sylvania didn't have this problem. I decided to try banderson's patented 407 in whiskey glass technique. :beerchug:

It worked pretty well. Some of the paint came off of the numbers on the station dial. They are hot stamped in so it should be too hard to fill them in with paint. The plastic is a bit dull from the white growth. I may try to polish up the clear plastic with Novus.

I'm not sure if I'll repaint the gold/brass. The patina kind of seems right for the age of the set. I noticed that one knob didn't have the gold paint in the center. This was true on my other Sylvania too. I thought it had worn off, but now I realise that they signified the power switch this way.

There's a very large opening in the top of the chassis since this version doesn't have the AM/FM radio. Mice seem to have used that to carry nuts into it. It didn't look like they were actually living in there.

I started to try to remove the 12VP4 so I could use my other set to test it. It turns out that whoever replaced it before replaced the pads and glued them to the chassis AND CRT just like the factory did. This makes it very difficult to remove the CRT. I'll have to remove the plate that holds the control knobs. Then it'll come off with the CRT. It's not too hard to pry it loose once it and the CRT are out. The service manual says to use a putty knife between the pad and chassis to loosen it, but that too scary for my tastes.

Schatzi didn't trust me either. He took cover as soon as I started on the CRT.

I hope to get it out and tested tomorrow.

John

Chardon, Ohio ! In my former life I bought a TON of diamond tools from an outfit there-Chardon Tool....The woman I talked to there, Nancy, was the boss or the boss's daughter. She was always very nice & friendly. These things were about the size of the business end of an ink pen, You'd put 'em in the engraver, sometimes they'd last a couple of weeks, sometimes they'd go "CHINGK !" & that was that. Most time they could be re-lapped, but $250 bucks a pop, half that for re-lapping, it was an expensive proposition. We prolly had a good 3-4 dozen between our plant, & there getting re-lapped at any one time. Sorry for the digression...

Wow - those cleaned up real nice :yes: I just ordered up a set of lacquer paint sticks (gold, blue, red, white, etc) to try filling in lettering on knobs and cabinets. I'll let you know how it goes in case you want to give it a try.

I love that picture of Schatzi. It goes well with AUdubon5425's avatar picture :D

I need to get a can made to cover the HV section though. It makes horrendous RFI otherwise. Anyone know where I can get a custom can made?

John

This may sound really stupid, but take measurements of the required size, and go shopping at the supermarket for some food you won't mind eating, that comes in the correct size can.

This may sound really stupid, but take measurements of the required size, and go shopping at the supermarket for some food you won't mind eating, that comes in the correct size can.

Sounds like a good idea to me. The only thing I wonder about is if the material matters. :scratch2: Most grocery store cans that size are steel and the one on my other Sylvania is aluminum.

I wouldn't think the higher mu would matter at the distance it is from the transformer even though the HV transformer is air core. I'm just not sure how to think about it.

John

Sounds like a good idea to me. The only thing I wonder about is if the material matters. :scratch2: Most grocery store cans that size are steel and the one on my other Sylvania is aluminum.

I wouldn't think the higher mu would matter at the distance it is from the transformer even though the HV transformer is air core. I'm just not sure how to think about it.

John

I don't know either, but perhaps a simple experiment with a coffee or large juice can would be in order. Aluminum canister sets in a cooking supply store, or perhaps eBay might be a source of the proper shield.
jr

I don't know either, but perhaps a simple experiment with a coffee or large juice can would be in order. Aluminum canister sets in a cooking supply store, or perhaps eBay might be a source of the proper shield.
jr

What, and trust real experimental evidence over theory! ;)

It'll be fun to see what reaction people have as I measure cans with a tape measure at the grocery. :screwy:

It's 5-1/2" in diameter so something like a coffee can might be close. I know people who can weld aluminum that thin if it comes down to needing to be non-ferrous.

I managed to get the CRT out. I should have realized I was doing something stupid when Schatzi hid in a box again. As I pulled the CRT forward the neck got stuck in the centering ring and the chassis was sliding on the wooden board I had it on as though it was on ice. When I tried to push it back in the board would just slide across the table instead of the chassis sliding back and the plate that was still glued to the CRT was now over the edge of the board so I couldn't set it down without having the neck snap. After some juggling I managed to get things under control again. I had to clean off some airplane cement that someone previously used to try to glue the base on the CRT.

Getting the plate off of the CRT was scary. I used CRC electronic cleaner to try to soften the contact cement. I was eventually able to remove it though one rubber pad tore. I didn't need to save them but they are hard and tough and I was afraid the glass would give.

The getter looks shiny so I think there's hope that I have a good 12VP4. I decided to give it a rest and try the swap tomorrow.

It's difficult to tell the difference between a 12VP4 and 12LP4 by just looking at them. The bell is the same, the neck on the 12VP4 is just shorter by about 3/4".

John

Well, I remeasured the can, this time with my reading glasses on, it's 5-1/8" in diameter. This is a standard can size, though not common. It would be a number 5. They specify them by diameter and it would be a 502 meaning 5-2/16". They do come in different lengths other than the standard #5 can.

Hopefully I can find one at the grocery. Surprisingly I found that they still sell these for home canning. But, the 502 can doesn't seem to be very common. At least not with the places that will sell individual quantities. I don't really want to buy a pallet of them.

But, if the grocery doesn't pan out I'll check with the one place that does sell that size.

John

Glad you are having some success with that old set!! I expected it would be better with you---than in my storage garage.

I hope the tube is good....or at least it will "wake up" for you.

I STILL don 't remember exactly where I got that tv. I THINK it was at an Estes auction--about 6 years ago or so.

I installed the 12VP4 in the 1-108 Chassis I have working. At first I thought the CRT was completely dead, but after turning the brightness up to maximum I was able to get a raster playing with the ion-trap magnet.

I let it play for awhile. The video shot looks better than it is because of the camera. It's barely visible in dim room light.

The scan line splits into two lines as it crosses the center. It should just get wide. I need to move the focus magnet forward. I think the apparent split is because the center of the cathode is pretty used up.

There is a pin point burn right in the center of the CRT where someone must have had HV, but no horizontal or vertical sweep. Or else it's just a defect.

I could try baking the cathode at a higher voltage. Rejuvenating it with any other method is out. I don't think even the Beltron knows about this tube.

So, do I send it to Scotty or modify the set to use a 12LP4 and keep this CRT as a collectible?

John

Looking at the dot pattern, I think that I am seeing a "hollow beam" that has less current in the center... perhaps the center of the cathode is "used up" or it may be ion damaged. I have seen cathodes where the coating in the center has been totally removed by ion bombardment, down to bare nickel.:eek:
If that is the case, It will not "wake up" with the application of 8 volts to the heater, but what have you got to loose by cooking it for a few hours?
jr

Looking at the dot pattern, I think that I am seeing a "hollow beam" that has less current in the center... perhaps the center of the cathode is "used up" or it may be ion damaged. I have seen cathodes where the coating in the center has been totally removed by ion bombardment, down to bare nickel.:eek:
If that is the case, It will not "wake up" with the application of 8 volts to the heater, but what have you got to loose by cooking it for a few hours?
jr

That what I was thinking too, a hollow beam.

I tried a brightener. That did little. I then cooked it, but the Beltron manual suggested 10 volts so that's what I used. It made it almost watchable, but it faded after a few minutes of use.

It's in a box and will be on its way to Scotty tomorrow.

John

It's in a box and will be on its way to Scotty tomorrow.

John

So Scotty will have a new cathode installed in the old gun?... or does he have a supply of the triode guns?

jr

The only thing I wonder about is if the material matters.
I have wondered that, too. From what I recall offhand, I have TVs with both steel and aluminum HV covers. Those with aluminum covers are 7-inch sets with RF type supply, Motorola VT-73 and National TV-7. Those with steel covers have flyback type supplies and higher HV. Of course, maybe the cheap little TVs used aluminum simply because they're cheap little TVs. Or, possibly I'm remembering wrong and there is no real pattern.

Similar question with ventilated vs. non-ventilated covers. Perhaps they should all be ventilated, but some are not because non-perforated sheet metal was cheaper. Judging by the melted wax I've seen dripping out of flybacks, some of those covers definitely could have used better ventilation.

No answers, in short, just more questions :) If you had steel & aluminum containers about the right size, you could do an experiment by holding each type of can over the supply and seeing whether the RFI is different.

Phil Nelson

So Scotty will have a new cathode installed in the old gun?... or does he have a supply of the triode guns?

jr

He will have the gun rebuilt. Hopefully there's nothing else wrong with the gun like an enlarged hole at the end of the gun. I don't know what all they can rebuild.

The gun in the 12VP4 uses ceramic supports instead of glass. I wonder if this makes any difference in the difficulty of rebuilding it.

John

I have wondered that, too. From what I recall offhand, I have TVs with both steel and aluminum HV covers. Those with aluminum covers are 7-inch sets with RF type supply, Motorola VT-73 and National TV-7. Those with steel covers have flyback type supplies and higher HV. Of course, maybe the cheap little TVs used aluminum simply because they're cheap little TVs. Or, possibly I'm remembering wrong and there is no real pattern.

Similar question with ventilated vs. non-ventilated covers. Perhaps they should all be ventilated, but some are not because non-perforated sheet metal was cheaper. Judging by the melted wax I've seen dripping out of flybacks, some of those covers definitely could have used better ventilation.

No answers, in short, just more questions :) If you had steel & aluminum containers about the right size, you could do an experiment by holding each type of can over the supply and seeing whether the RFI is different.

Phil Nelson

Since the flybacks have a core I would guess any influence an iron cover would have would be minimal.

You tempted me to look up the price of 1950 aluminum and steel because I once remember reading that before 1855 aluminum was more valuable than gold and that Napoleon III reserved the use of aluminum dinnerware for his most important guests.

Aluminum was $350/ton and steel was $47.20/ton in 1950. I think they would have gone with steel based on cost. I'm not sure how fabrication costs would differ.

My 1-108 chassis has the aluminum can. I can do the steel vs aluminum test with it. The can in my 1-108 does have ventilation hole along the top and bottom with a note on the can that they must be aligned vertically. There's a 6Y6 and 1B3 in the can and it gets quite warm. I'm tempted to stick a thermocouple in, but I might zap myself that way.

John

John, I never has one of those Sylvania sets with the 12VP4. But I admire any 10 or 12 inch cRT set with a RF high voltage supply.

I forgot that aluminum is about 1/3 the density of steel. So it's only 3 times as expensive in 1950, not over 7 times.

John

John, I never has one of those Sylvania sets with the 12VP4. But I admire any 10 or 12 inch cRT set with a RF high voltage supply.

I might be reading too much into your comment, :scratch2: but I don't think a 10" or 12" CRT makes much of a demand on a properly designed RF high voltage supply. Spellman made an after market RF HV supply for projection sets in the 50's.

I had some trouble with mine at first, but after selecting a good 6Y6 I get plenty of HV and it's quite stable. It also seems to have gotten better the more I use the set. Perhaps the transformer had absorbed some water.

John

Admiral, Motorola and Hallicrafters all used aluminum shields for their RF HV supplies. I'm not sure, but I bet it has to do the effect of ferrous alloys on the coil.

Admiral, Motorola and Hallicrafters all used aluminum shields for their RF HV supplies. I'm not sure, but I bet it has to do the effect of ferrous alloys on the coil.

I hope to find out after going grocery shopping today. I've been taking a few days of vacation.

Phil mentioned ventilation holes. I forgot to mention that besides the holes the can on my Sylvania is painted flat black on the inside and outside. I think this was to radiate heat better.

JOhn

Well, there were lots of #5 cans at the grocery, but they were made of paper. I thought this might be a bad idea. I found only one metal can the right size. It was decaffeinated off brand coffee. I don't see the point without caffeine.

I tried it on the Sylvania that I have working that has its aluminum can. The coffee can is a bit longer, but I didn't trim it down because with the OEM can there are 6Y6's that are too long to fit and the cap of the 1B3 is very close.

I swapped the cans back and forth to make sure there wasn't any warm-up effect biasing the measurements.

With the OEM can I measured 9.75KV. With the steel can I measured 8.98KV. I should have tried adjusting the trimmer capacitor, but I spent so much time getting it where I wanted it I didn't want to disturb it. The steel can might be causing losses, or it might only have shifted the frequency.

When I restore the 1-125 I might use it because after painting it black, it'll look pretty original. If it causes problems I'll make one out of aluminum, but it won't be as pretty.

John