I buffed out the safety plastic with some Novus. There are still a couple deeper abrasions but it's a lot better than it was.

The picture has never been particularly bright, but I figured that was just due to the age of the picture tube. Well, I was about to put it together when I decided to check the HV with my Pomona probe.
It's only 6 kV when it should be about 7.5 kV. I also did a dry run an discovered I can't get the vertical to fill the whole visible screen. I guess I have a little more work left :o

http://farm6.static.flickr.com/5218/...3c7f570f_z.jpg http://farm6.static.flickr.com/5218/...8f3e7bac_z.jpg

Yes, I repaired the defective ballast in my VT-71 with a pair of AC rated capacitors (plus 2 resistors), and it works well, and runs cool. As I recall, I think the caps were 8.2uF for this set. Have to verify that when I get back in the set..

Have you checked the B+? Just curious if it were possible for that being low to cause lack of vertical size and lowered HV at the second anode.

Please don't scrap your Zenith, someone will eventually come along and get it running for you or buy it.

I'd love to have a look at it but I'm too far away!

Yes, it's dead on. If I vary it using a variac, the vertical and HV don't change much. I hope it's just a matter of some resisters being off.

Agreed! That sounds like a rare and nice zenith. If I was on the east coast I'd be willing to take it off of your hands. If you take it to the ETF convention in Ohio I'm sure someone(possibly me) will be more than happy to buy it.


For me the reason I repair is for the challenge, and that high I get after finding and correcting a really tough bug. that and seeing somethimg over twice as old as me working like new, other things like braging that nearly every thing I own works etc. come second. There are exceptions to the if I can't fix it it gets sold or donated to the local radio club rule. I'll hang on to anything that I like the look of (especially art deco) also coveted sets like any color set that may have originally used a NTSC standard phosphor tube, any TV pre-1950, anything with a remote, any radio with a tube count of 14 or higher and anything that I want to have in my colection that I don't think I'll find again. Case in point I'm using a Philco beam of light (which is out of wack except for the amp) as the head board of my bed. I also have a policy of not parting out anything pre-1970, however I once made one nice radiola model fourty-something out of two messed up ones(forgive me father for I have sinned:sigh:).

Please do not scrap that Zenith!

Tom C.

I really think that I could get it going myself as it is already recapped, but the problem lies deeper than that. I have posted on this before so I sort of hate to go off topic, but anyway the biggest hindrance of repair of this set is simply not having a way to power the chassis to do voltage checks and if I had a scope I would look at waveforms. The big 24" tube does not come out with the chassis, nor does the tuner, so I would either have to build a jig to hold the crt, or make necessary extension leads for the yoke and second anode HV connection; I could just unbolt the tuner and motor. The easiest and best approach would be to get lucky and find one of those small test crts to power the chassis. Anyway, I just didn't have the heart, or lack thereof to bust up the Zenith. With no interest in the set I have made further attempts at finding the problem. I used a megger to check out the vertical output transformer and the choke (while I was already close by) for grounded or open windings. I did a little probing around with a Huntron Solid State Tracker, but that is best used to compare footprints with that of a known good component in a similar or identical circuit. Really, it all boils down to good old signal tracing I think. I may just bite the bullet and build a wooden jig for that crt and get the job done. A low use, big screen 50s set with remote control would be a GREAT daily user I think. Oh, the remote is missing, but I think that they are pretty easy to find.

Thanks for the encouragement! :thmbsp:

I did some probing and found the 410V derived from the 420V boost was only around 350V. I measure R78 and it was high - about 8K.
I replaced that and got full height even though the 410V line was still low at 380V with 8V P-P of ripple.

Unfortunately, while I was adjusting various controls the picture starting breaking up. Then I completely lost the video and sound. I still have a good raster and all the controls respond.

I've already checked the tubes and replaced a weak 3CB6. The 5J6 is a little weak too, but I couldn't find a replacement so I tried a 6J6. That didn't make any difference.

I'll fire up my 1077B and try injecting signals at various points in the RF/IF stages. I hope it's something simple.

http://www.bobandersen.com/images/Ad...T102/boost.jpg

http://www.bobandersen.com/images/Ad...t%20ripple.jpg

I fixed the set (again) :banana:
It took a while, but eventually I found this bad resistor hiding under a coil :rolleyes:
http://farm6.static.flickr.com/5298/...68e6a9be_z.jpg http://farm6.static.flickr.com/5172/...70d4ea92_z.jpg

That supplied +130V to the 2nd IF stage. That's right before the detector so no picture or sound. I replaced it and got the picture back but no sound.

More troubleshooting revealed the coupling cap between the volume control and audio output tube had a broken lead. I quickly soldered that back on sound was restored :music:
http://farm6.static.flickr.com/5138/...fb5beb3a_z.jpg

Better yet, I have full vertical although the control is near the edge of it's range. I'd still like to find out why the 410 line is a little low :scratch2:
When I first popped this set open, I found a 1.8K resistor someone had added between the 410 line and 10uF filter cap.
That seemed odd and I removed it. It might be worthwhile to put it back. Doesn't seem like adding a resistor is going to increase the voltage though.
http://farm6.static.flickr.com/5256/...7f21a891_z.jpg

Also, replacing the weak 3CB6 increase the gain and I have a brighter picture.
Odd that it and the 5J6 test weak now when they were good a couple weeks ago.
Maybe running this set for a few hours drained what life they had left ?

The picture is off-center to the left a little, but I can take care of that by adjusting the ion trap magnet or centering magnets.
http://farm6.static.flickr.com/5294/...1216603f_z.jpg

I put the set back together and it's playing well.
Sometime later this spring or summer I plan on repainting the cabinet.
I think I'll try using electrolysis to remove the rust and hopefully the paint too.

http://farm6.static.flickr.com/5056/...dbdcf338_z.jpg http://farm6.static.flickr.com/5133/...0f6e1c9e_z.jpg http://farm6.static.flickr.com/5260/...76815275_z.jpg

Tubejunkie since you did not want to go off topic I sent you a PM with some suggestions.

Tom C.

I masked off some of the orange on my paint test subject and put on a few coats of "Ivory Bisque" followed by a clear coat of the engine enamel. I think it looks great and is very tough :)
I examined the cabinet and it appears they also painted the whole cabinet orange first, than applied the white. Odd - I would have done it the other way round :scratch2:

http://farm6.static.flickr.com/5292/...ac55a79b_z.jpg

Here's one for sale in very, very nice condition! http://cgi.ebay.com/Vintage-1957-2-T...-/290541493996 (no affil.)

Is this plaid cover original ? It sure looks like it.
http://i.ebayimg.com/00/$(KGrHqYOKkI...Log+hg~~_3.JPG

That is an original cover, I've seen ads with those in them.

I Picked up some aftermarket plastic covers on eBay in Red and Pink for my Hotpoint/GE 9" and 14" sets.

They were NOS with the boxes but they had shrunk somewhat and it was a bit difficult to get them on the TV's

The Emerson 1232 8" Portable also had a zippered carrying case, I have one but it's falling apart at the seams and is stiff with age.

maybe they used those covers as a work-around for the hot chassis issues those sets had.

Green T-103
 

I have just had a mint condition T-103 as a gift: as all tv has switched to digital, few enthusiast want to mess up with VHF modulators.
I think it's a very rare set to find in Italy: actually I've been told that it belonged to a wealthy US family living in Milan.
In 1956 few people owned a TV, (they costed like 5-6 month wages) and no one was already caring for a kitchen - or holiday house - set.
The body is near perfect, inside is very clean. I've been told that it works, but I want to check it for leakages first, using a variac and isolation transformer.
Export sets like this have an additional auto-transformer to adapt to different line voltages, 220 included. And of course they are tuned to the 625 lines - 5.5 MHz intercarrier used here.
I have a schematic but not the SAM's service manual ...
Thanks for all the advice on this thread, I hope to begin working on it soon !
:thmbsp:

I scanned the Sams for the 14YP3 chassis and you can download a copy here

It may be of some use to you. Good luck.

A good source for dropping capacitors is old ceiling fans, you'll find them in the switch housing.

The green T-103 I'm working on, as I said, was sold in Italy. It differs from the US market models in the power supply (see schematics). It's got an autotransformer. This increases the weight, but has a great bonus: it gets rid of the 20W resistor with an 85V tap for the heaters !
Additionally, it provides 220V for the B+, so that a voltage doubler circuit is not necessary, and the 2 selenium units are wired together.
I'm slowly conditioning the capacitors with a Variac now ...

We've finally climbed out of the 30s so it's time to repaint this cabinet :D

I picked up a tub big enough to submerge the cabinet. I filled it with some water and Washing Soda (Sodium Carbonate).
I used a 2A/10A battery charger for the juice and a big old cold chisel for the sacrificial iron.
http://farm6.static.flickr.com/5305/...b99797cd_z.jpg

I was really surprised that the paint was bubbling off in only 30 minutes!
A few hours later and it was all off :)
http://farm6.static.flickr.com/5069/...d5bd3b69_z.jpg http://farm6.static.flickr.com/5187/...a33a9081_z.jpg

It worked even better on the orange paint.
http://farm6.static.flickr.com/5307/...d8d55aee_z.jpg http://farm6.static.flickr.com/5224/...945a4cfc_z.jpg

I had some gray and maroon primer on hand and used appropriately.
http://farm6.static.flickr.com/5174/...cbc94750_z.jpg

Now it's time to pull the chassis and dunk the rest of the cabinet.

The paint is coming off the main cabinet nicely too :)

http://farm6.static.flickr.com/5142/...67398066_z.jpg http://farm6.static.flickr.com/5029/...c49aa179_z.jpg http://farm6.static.flickr.com/5227/...3b653817_z.jpg

For those of us not well versed in electrolysis (me) could you explain what you've done and what the various pieces do during the process please?

I've only used it to remove rust before and was surprised at how well it lifted the paint off. Here's what I did.

* Fill a tub with water and sodium carbonate.

* Connect the negative lead of a battery charger to your rusty/painted item. Any power supply that puts out 10-15 volts at 1-2 amps should work OK.

* connect the positive to a piece of iron or steel. Don't use anything with Chromium in it. That might produce toxic compounds.

* Submerge them both in the tub, but DO NOT allow them to touch.

* Kick back and wait a few hours.

If you're removing rust, it should turn black. If you're removing paint, hopefully it's lifting off. I've heard it doesn't always work.
Use a wire brush or scouring pad to remove the black stuff / paint.

Clean the bare metal thoroughly and get some primer on it before it's starts rusting again.

If you search the web for "rust removal electrolysis" , you'll find a lot more info and tips.

I apologize beforehand, but I'm a details kind of guy.

Does it matter the ratio of water to sodium?

What does the chunk of steel do? Is it some kind of catalyst, or is it used up somehow in the process?

If I come up with anything else I'll check your provided sources.

Something like 1 tablespoon per gallon. The chunk of steel will get eaten away in the process.

I finally got all the paint off the main cabinet body and sprayed it with primer.
http://farm6.static.flickr.com/5144/...55f8316b_z.jpg http://farm6.static.flickr.com/5309/...6cc72c08_z.jpg

How hard was it to remove the paint after the electrolysis loosened it?

Phil Nelson

Not hard at all. A little wire brushing took 95+% off. I used some citrus based stripper to loosen up the rest.

The stripped chassis sure looks nice. I'm curious how the overall mess/work equation compares to using plain old stripper. Also, we live in the sort-of country and have to be careful about what goes into our septic system. Dumping big tubs of chemical gack down the toilet isn't always a good idea.

Phil Nelson

I scrubbed the paint off outside of the tub. So what's left in it is mild soapy water and some fine rust particles. I let it settle for a couple days and poured the soapy water down the drain. I poured/scooped the rusty sludge into a coffee can and disposed of it.

That's really neat! I soaked mine in a 5 gallon bucket of carburetor dip, talk about toxic!

If you stuck some Chrome (or Gold) in the tub and reversed to polarity what would happen? :scratch2:

A chrome TV might be kind of cool.

I think it might work if you used the right electrolyte. I've heard chrome compounds are pretty nasty though.

-
I sprayed on a couple light coats of the Ivory Bisque then let it dry and sanded. Then another two coats and sanding.
http://farm6.static.flickr.com/5146/...37dffc73_z.jpg

Here's a preview before I sprayed the bottom. I think it's gonna look pretty sweet :)
http://farm6.static.flickr.com/5187/...2c7a5de8_z.jpg

Next, I masked off the white top and sides and sprayed a few light coats of orange.
http://farm6.static.flickr.com/5144/...432d7f06_z.jpg

After it set up about an hour, I carefully removed the blue tape. The orange bled through in a couple spots, but it's not too bad.
I think a little careful sanding will take care of it. Then, I'll put on some clear coat and let it cure for a week or so.
http://farm6.static.flickr.com/5024/...545757e5_z.jpg

buddy of mine picked up one of these, took the back off, noticed a black wire that comes from the brightness pot looks like it was maybe soldered to the chassis ground, does that sound right?

Yes, one side of the brightness pot is grounded. You can download the Sams here.

Here's how the cabinet turned out.
http://farm6.static.flickr.com/5236/...279a5d02_z.jpg http://farm6.static.flickr.com/5022/...9eb94222_z.jpg

Hey!
Just read this entire thread and wow, what a phenomenal job you did! The cab came out great

Thanks! I still have the chassis out as I want to do a little more work on it. I found the 5J6 in the tuner was weak and it took me forever to track a good one down.
Also, the vertical height isn't as good as I'd like and the horizontal linearity stinks.

I think this holiday weekend will be a great time to finish it off :yes:

Nice paint job. How did did you remove the labels? That's if you were going to save them. Mine look like they are so dry they would practically fall off.

This holiday weekend I have choice between the the T102, the 721ts or the 20x12. :scratch2:

It took me less than a minute to track down a 5J6. This is one of my favorite suppliers and Stan has a good stock of oddball/tv type and other tubes.

http://www.esrcvacuumtubes.com/

Mine were practically falling off too. I used a razor blade to carefully get them off. I also made scans so I can reproduce them.

Thanks for the tip, but I meant without ordering one. I have a stash of several 1,000 tubes that are unsorted. Many were unboxed too. I went through all of them and boxed and sorted them :drool: