Need Help: Dead Zenith B25A11Z Chassis 9-2108

[MarkC]

I don't have a tech manual on this one. The 9 volt reg ICX3401 is not
getting any voltage input. This one tries to start up but the HV only
gets up to a few KV & that's it. So far I've subbed ICX 3400, QX3601,
CX3416, CX3413, the VOUT chip & the tuner (some of these short out).
D3410 & R3406 check OK. ICX3402 has 5v output. The HOUT has 132V at the
collector. ICX3400 has 160v in & NEG -42v out. I also replaced the micro
crystal.
There is no voltage at FX3402. Thanks for any suggestions.
Mark

 

[David Harris]

Mark

What you have written seems to point away from power supply
problems. You've pretty well covered the bases there.
Have you considered that the IHVT may be your problem? I have
changed enough of these that I stock one. I do think I have seen ones
that do indeed develop a few KV before the PS gives up and shuts down.
Also, I should mention that the voltage at FX3402 is not DC, in
case that's what you're looking for. Look for 15VDC stand by at D3411
to see if that part of the PS is running.
The IHVT part number is 095-04372-01.

Good Luck

David, on the Illinois prairie.

 

[Mr. Lee]

Module exchange will repair the board

 

[MarkC]

Thanks for your advice David. The flyback was on my list of suspects but
it was the last thing I was going to sub out so thanks for your input. I
thought it was in shutdown but it was not starting up. It was the first
time I'd had to replace a fly on these usually it's bad caps or the REG
& associated parts.
Mark


"What you have written seems to point away from power supply problems.
You've pretty well covered the bases there.
      Have you considered that the IHVT may be your problem?
I have changed enough of these that I stock one. I do think I have seen
ones that do indeed develop a few KV before the PS gives up and shuts
down.
      Also, I should mention that the voltage at FX3402 is
not DC, in case that's what you're looking for. Look for 15VDC stand by
at D3411 to see if that part of the PS is running.
      The IHVT part number is 095-04372-01.
Good Luck
David, on the Illinois prairie.

 

[MarkC]

I only replace modules as a last resort & never on 27" or under TVs
because it's not worth it considering the replacement cost of a new
comparable set.

"Module exchange will repair the board"