Finlux 32FLD760P No picture

[mitsu79]

No picture, sound ok.
Turns on from standby ok, backlight lids, but no picture, if I try to change channel or go to menu, backlight dims or brightens just a bit.
This is elderly persons tv and I only have secondhand info about symptons before it went blank: Theres been picture problems from new, color problems, flickering? (not sure and not sure how to say this in english, but maybe, rapid picture movement left to right etc. from time to time). Picture have had lines and blurred unwatchable, before it went totally black.
Could this be PSU issue and maybe be repaired with PSU repair kit or MB or something else?
PSU: 17PW20.1
MB:17MB22-2

[tom66]

Re: Finlux 32FLD760P No picture

Very common issue with this PSU.
Two major known issues:
- C878/C877 capacitors fail (cheap and easy fix)
- PFC circuit fail (causes main capacitor voltage to drop from 390V to 320~340V)

The problem sounds more like C878/C877 personally to me.

[mitsu79]

Re: Finlux 32FLD760P No picture

Thanks, what capacitance should C878/C877 capacitors have?

[gilly1984]

Re: Finlux 32FLD760P No picture

15nf 1600v

[tom66]

Re: Finlux 32FLD760P No picture

I've seen as low as 400V used on these PSUs... I would recommend min 800V replacements.

[mitsu79]

Re: Finlux 32FLD760P No picture

Ok, I'll try to measure them, if my multimeter have heated up over radiator, my garage thermometer says -6 celsius... outside about -20C

text on capacitors: mmkp82 153j630

[mitsu79]

Re: Finlux 32FLD760P No picture

Both capacitors were 34nF?

[tom66]

Re: Finlux 32FLD760P No picture

Did you measure them in circuit?

[mitsu79]

Re: Finlux 32FLD760P No picture

In circuit, yes.

[tom66]

Re: Finlux 32FLD760P No picture

Those you need to measure out of circuit.

[mitsu79]

Re: Finlux 32FLD760P No picture

Ok, I'll remove and measure them again later today.

[mitsu79]

Re: Finlux 32FLD760P No picture

C878/C877 were both 13,7, new ones I got measured 13,9.
I think those old ones still work, only my multimeter ain't very accurate anymore.

what shoud I check next?
(I got repair kit including C801, C892, C901, C817, IC829, C877, C878, R817, R818,R819).

[mitsu79]

Re: Finlux 32FLD760P No picture

I replaced all but SMD resistors, they measured ok. 33uF condensator was 25uF, all other old parts measured more of less same as new ones(excluding transistor, not sure how to measure them). I'm somewhat sceptical, that problem were within these parts, but haven't got chance to test the PSU yet.

[mitsu79]

Re: Finlux 32FLD760P No picture

Tried it today, no differense, backlight turns on, but no picture.
I measured some voltages and I don't think that the problem is in PSU, what could i try next?

[tom66]

Re: Finlux 32FLD760P No picture

What voltages did you measure?
Did you check the voltage across the big 450V capacitor?

[mitsu79]

Re: Finlux 32FLD760P No picture

Main cap was 385V, others were 24,5v 12v 2v 3,3v 5v and yellow wire mentioned "https://www.badcaps.net/forum/showthread.php?t=25740&highlight=32FLD760P&page=2" post: 32, was 12v as it should.

[tom66]

Re: Finlux 32FLD760P No picture

Those are good, so I would say looking elsewhere would be a good idea.

[mitsu79]

Re: Finlux 32FLD760P No picture

I think so also.
Which one is T-CON board and is it same as graphics board?