25EC58 Tripler Question?

[jstout66]

I am trying to help a fellow VK member figure out what tripler he has in his set. I think Bryan is looking as well.
The VK member has a repair guy that will work on the set, but not chase parts. He was told the tripler is bad.

Symptom--- set comes on with a totally normal picture for about 5 seconds and trips the breaker. Since I am so weak in SS repair, I assume the tripler is overloading the hot, which is causing the breaker to blow? I was trying to determine how the repair guy has determined the tripler is indeed bad.
The only ones I saw that went bad caused a no high-voltage, bad focus, or arching symptom.

Issue: Zenith used 2 triplers during that chassis run. One with an internal focus block, one without. Now if memory serves.. the one without an internal focus block would have two red wires running to the anode cap?

I have asked the VK member to ask his repair guy the exact Zenith part number, but unsure if the tech will do it.

The Sams on that set should be 1370-2, but don't think that would help without knowing what tripler Zenith used.

Any suggestions/advice.

[radiotvnut]

An NTE526A is the version with the internal focus block and it can be used to replace the seperate tripler and focus block components. In fact, that's what I'd do because those seperate focus blocks gave trouble and they are getting harder to find.

Not saying it can't happen; but, I've never seen a tripler that caused the symptom described. They would either arc, cause focus problems, or short internally. When they short, they can take the flyback and HOT with it. I've seen that problem a lot, especially on the vertical chassis sets and once on a flat chassis set.

When I suspect a tripler, I lift the HV input lead to the tripler and isolate it so it does not arc to anything. If there is HV at the lead and if the CB stays in, the tripler is bad.

[jstout66]

okay... now I hope this next question isn't too stupid, but what if his set is NOT the one that uses the seperate focus block? WIll the NTE526A still be the proper tripler?

As well also, I concur on thinking it may NOT be the tripler, but that is what his repair guy told him....... I NEVER saw that symptom either, but it's been so long since I dealt with a Chromacolor, I can't rember what WOULD cause the symptom he's having. I think it's a flat chassis set......

[radiotvnut]

Yes, the 526 has the built-in focus resistor and is a direct replacement for the original Zenith tripler with the built in focus resistor. I actually have a 25EC58 flat chassis and the tripler in it crosses to an NTE526 and it is the one with the self contained focus resistor. I think the tripler is actually bad in my set. It has HV; but, the picture is too bright and there does not appear to be the proper output at the REF terminal on the tripler; which, is tied in to the brightness limiter circuit. That set is buried right now and I'd like to fix it; so, I'll someday be looking for an NTE526 myself.

[mercury6768]

Just to wrap up this thread: the NTE526A was the correct replacement tripler for my Zenith Avanti, chassis 25EC58. It was arcing whenever power was applied, which caused the breaker to trip. Once J was kind enough to send the part, my TV repairman installed it, adjusted the set, and now it looks great!