1970s Zenith Console - Troubleshooting

[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.

[ThePlague]

I went to check HOT collector to ground and sure enough there was continuity. There was also continuity between the HOT collector and emitter. I took the HOT out and rechecked the circuit without it. The collector side of the circuit was no longer grounded.

Long story short my HOT has failed and I was checking continuity for the collector (threads) incorrectly. There is a short from collector to emitter and collector to base. I will be sourcing a replacement.

I have also attached the requested pictures of my 22-5001 caps. They are in for troubleshooting rather than looks at the moment.

Update 1: From a quick glance, the Zenith replacements are all but gone. I was able to find sources for the RCA SK3115, Sylvania ECG165, and NTE165 replacements. Of course OEM is preferred, but is there any pecking order on other brand replacements?

[BeamT]

From Zeno the Zenith 212-139 crosses to a 800-791 in the Zenith Replacement line of triplers. I can see the same information. Also crosses to a NTE/ECG 521 if you are willing to stray to a non-Zenith part. In both the 800-791 and the NTE/ECG 521 there is a focus tap that is unused in this application, so you clip the lead and cover it over with silicone.

From everything I can find the original 212-139 was a 6 step tripler, rated at 30KV max, no focus tap. Sams indicates the Focus Divider is 200meg tapped at 40 meg. It appears to me the NTE/ECG 530, Zenith 977-9530, is close. They are also 6 step triplers, rated at 30KV max, with an internal divider, 240meg tapped at 40meg. Sams indicates we should see 25KV at the CRT, and there is no adjustment.

I haven't found any documentation/information this was a recommended replacement for both the tripler and the divider, but I know this was done back in the day.

It would be nice to hear from anyone that has gone down this path. I asked the same question in my thread about a single replacement for both.

Hope this helps, good luck with your set.

[BeamT]

Good catch with the HOT. I always had good luck with ECG 165. Be mindful of the insulator and the heatsink compound. The tripler may still be bad, and took out the HOT. You know the the divider has been arcing at some time in the past.....