1970s Zenith Console - Troubleshooting

[ThePlague]

Hey Reno,

I'll take a look at that this evening. To be honest, if I can find a tripler that has an internal focus divider I wouldn't mind swapping it out rather than dealing with that orange blob. I remember a forum post listing suitable replacements if I can dig that up.

I hope that something truly failed given the original power on event of a sulfur burning smell; that would make diagnosis much easier.

[BeamT]

+1 on Zeno's last reply. In addition to the damper I would also investigate C261 which is just off the collector of the HOT. I'm looking at Sams 1312 and that cap may actually be a "feed thru" It will have a pin on each side of a flange, the flange is grounded, usually soldered to the chassis or a metal bracket. Sams lists this cap as 22-5395 .001 @ 1.2kv

If you are interested, google for a YouTube:
"Troubleshooting the 1973 Zenith 25DC56 Color Television Chassis" by drh4683.
Very good video, methodically troubleshooting the same chassis and circuits you are working with. Breaker popping, he locates a shorted safety cap. There may be a view of C261 in the video. He is also troubleshooting with the Zenith CM manual.

I am working on a 25DC56 and posting in the Solid State sub-forum. I haven't attempted to power my set up yet. I'm waiting on the safety cap subs from Mouser. If any of mine are open, I wouldn't be running it that way for any length of time, and if any of mine are shorted, not going anywhere anyway. So replacing them first is a good initial step, troubleshoot the rest after that.

My tripler, 212-139 is original as is my 63-9012-2 focus divider.

The red blob is your focus divider covered in HV-putty, was a replacement that started to arc. Sams lists 63-9896 as a replacement. I'm not sure about that....

[BeamT]

BTW I'm away from my set or I would have checked for C261 and sent a picture.... If it is a "feed thru" it doesn't look like a typical capacitor.

[ThePlague]

Hey Todd,

That was my first suspect cap. I have actually watched the video you mentioned and picked up a few tips from that. I am also using a Sams and its proven quite handy when identifying chassis components.

C261 is a weird little thing. It is however the last component before my safety cap that got nice and toasty. I'll have to take it out of the circuit and test it.

Should you have any issues getting your safety cap replacements, I have a Zenith 22-5001 OEM replacement and a Associates equivalent left over. (I thought there were 5 safety caps, but I have only seen 3 so far)

I greatly appreciate the help!

[BeamT]

It is a feed thru, its located in the bracket that is immediately to the side of the HOT socket. one end is connected to the yellow wire. It looks like a resister with a collar around it.

Not sure how you feel about your past steps but this might be a good time to regroup and repeat and verify some of your work. Zeno's advice is quite sound.

Can you post a picture of the 3 safety caps you replaced?

Have you checked the damper diode?

You can check the feed thru cap with an ohmmeter but that does not rule it out as a problem. It may not be shorted with a DC voltage present but if you put the screws back into the HOT, the horiz circuit will start and the AC voltage there is quite high. From the HOT socket, collector pin, what sort of resistance to ground are you seeing?

[BeamT]

NVM, you are correct. I needed to look closer. There are 2, one on the base, the other, you have circled, is the collector.

[zeno]

Usually 2 caps are on the flyback & 3 more under the chassis.
If any got changed to orange ones you may miss them.
Feed thrus are known to go but its rare. I think I had 2 or 3
all on the 13GC10 13" chassis.
I did see a NOS triple at one of the distributors BTW. Try to stay original.
BTW I hope that putty was put on by the owner. If it were a tech
I would fire him. Lucky they didnt see fire trucks !!

Zeno

[ThePlague]

Originally Posted by BeamT

It is a feed thru, its located in the bracket that is immediately to the side of the HOT socket. one end is connected to the yellow wire. It looks like a resister with a collar around it.

Not sure how you feel about your past steps but this might be a good time to regroup and repeat and verify some of your work. Zeno's advice is quite sound.

Can you post a picture of the 3 safety caps you replaced?

Have you checked the damper diode?

You can check the feed thru cap with an ohmmeter but that does not rule it out as a problem. It may not be shorted with a DC voltage present but if you put the screws back into the HOT, the horiz circuit will start and the AC voltage there is quite high. From the HOT socket, collector pin, what sort of resistance to ground are you seeing?

I will check this this evening and go back through and verify.

Originally Posted by zeno

Usually 2 caps are on the flyback & 3 more under the chassis.
If any got changed to orange ones you may miss them.
Feed thrus are known to go but its rare. I think I had 2 or 3
all on the 13GC10 13" chassis.
I did see a NOS triple at one of the distributors BTW. Try to stay original.
BTW I hope that putty was put on by the owner. If it were a tech
I would fire him. Lucky they didnt see fire trucks !!

Zeno

I didn't see any other orange ones that looked like my replacements. Looking through the SAMs I only see C268, C267, and C265 listed as 22-5001 capacitors. I replaced the 2 on the flyback and the one right after the HOT. Do you happen to know the designations of the other 2?

I was looking online and had no luck finding a 212-139 tripler for sale. Fingers crossed this one is okay. However, that focus divider is a mess. I do plan on replacing that at least if the tripler turns out okay. This was a one owner set and based on its heavy usage I doubt it was done by the owner.