Panasonic TC-32LX85 Dead

[kevinm34232]

Re: Panasonic TC-32LX85 Dead

Ok let me look...

[budm]

Re: Panasonic TC-32LX85 Dead

I just want to be sure, above you said use a 4.7uF 50V on the VCC pin?

I just want try with the small value first to see what effect it will have.

[kevinm34232]

Re: Panasonic TC-32LX85 Dead

All I have is a used 22uF 25V, and some new 10uF 16V

[budm]

Re: Panasonic TC-32LX85 Dead

You can try the 22uf for testing on the VCC pin, but I have a feeling the C7011 should be bigger than 4.7uf as it is right now.

[kevinm34232]

Re: Panasonic TC-32LX85 Dead

OK with the 22uF 25V cap attached across pins 2 and 3, relay is clicking on and off, over and over, VCC gets up to about 14.5V before it clicks off but it won't come on.

[budm]

Re: Panasonic TC-32LX85 Dead

OK, move that cap to where C7011 (4.7uF) is.

[kevinm34232]

Re: Panasonic TC-32LX85 Dead

OK did that, same reaction with clicking and same 14.5V VCC voltage.

[budm]

Re: Panasonic TC-32LX85 Dead

That is really strange symptom. I am ready to suggest to connect the VCC circuit like it is shown in the application notes but sure like to know how it works before the way is it connected right now.

[kevinm34232]

Re: Panasonic TC-32LX85 Dead

Its clicking seems like it just doesn't have quite enough voltage to start up, but a lot closer than before when it was mostly just dead.

[kevinm34232]

Re: Panasonic TC-32LX85 Dead

Anything else I can check, I'm no expert reading the schematics but is VCC coming from pin 3 on T7001? Could D7005 be leaky? Is this being cause by the O.L.P., or just low voltage to the VCC pin?

[budm]

Re: Panasonic TC-32LX85 Dead

The VCC must have got to 17V minimum startup voltage because it does startup, but then it goes into cycling mode so the VCC is cycling up and down. Do you have power supply to test Zener diode, I do not know the value of that D7005.

[kevinm34232]

Re: Panasonic TC-32LX85 Dead

Yes I have a power supply. Im just wondering if I can trace that VCC line to see where it's originating and where it might be going low or isolating it. Can I lift D7005, is it likely something right in that area?

[budm]

Re: Panasonic TC-32LX85 Dead

OK, I would like to try something, put 100 Ohms 1/2W in parallel with D7008 and see what happen (I am bypassing Q7000 with resistor).

[kevinm34232]

Re: Panasonic TC-32LX85 Dead

I got the new 4.7uF 50V caps and replaced C7011 again and the TV came on. Ill have to test it for a bit.


Well I just went back and plugged in again and same clicking has returned, grrr. Ill try the resistor next.

Could that cap be getting 'damaged' when the TV comes on, because it did the same thing when I replaced it last time?

[tom66]

Re: Panasonic TC-32LX85 Dead

It would be unlikely to be being damaged, more likely something is intermittent. Maybe the soldering heat is helping temporarily cure the fault.

[kevinm34232]

Re: Panasonic TC-32LX85 Dead

I tried the resistor idea from Bud, same clicking.

Could the A6159 IC ever fail like this?

[kevinm34232]

Re: Panasonic TC-32LX85 Dead

Maybe you're right about the heat, I just resoldered all the pins in the circuit in case of any bad joints, and the TV came back on. Ill let it cool back down now.

Would there be any likely suspect parts if it was heat (caps, diodes, resistors) or any of them?

[kevinm34232]

Re: Panasonic TC-32LX85 Dead

Cooled down and now completely dead again.

[tom66]

Re: Panasonic TC-32LX85 Dead

With TV clicking, set your iron to a low temperature (150C or less) and touch it against the A6159 IC, does it stop clicking and start up? Be careful not to touch any pins with it, as your soldering iron may be grounded which would probably blow the fuse or do other damage. Also don't hold it there for more than 10 seconds if it doesn't react.

[kevinm34232]

Re: Panasonic TC-32LX85 Dead

Right now TV is dead, there is a little < 14V at the VCC pin. I added some heat with the iron and no result. I have a hot air station should I just heating stuff up around there?