Finlux 32FLD760P with Vestel 17PW20.v1

[tom66]

Re: Finlux 32FLD760P with Vestel 17PW20.v1

That wiring can cause a lot of problems!

It has high inductance and resistance and you need to install them on the board directly.

[Serkai]

Re: Finlux 32FLD760P with Vestel 17PW20.v1

Guess that sets the verdict, alright I'll go ahead and do that!

I hope the picture was ok for marking where to check?

[tom66]

Re: Finlux 32FLD760P with Vestel 17PW20.v1

Fix that first & see if it sorts your issue, if not we shall check other things. Pic is fine for basic checks.

[Serkai]

Re: Finlux 32FLD760P with Vestel 17PW20.v1

Okay, I took the time to resolder some other connections as well since I've read that this board has problems with cold soldered joints.

So far, so good, the tv works and does so very well, but I really do fear it will not last because it worked this good once before when I was looking inside it, only to start failing on me after a couple of hours.

[Serkai]

Re: Finlux 32FLD760P with Vestel 17PW20.v1

Ok, so now 2 hours later the problem is slowly coming back, there's some white flickering going on but not as bad as before. Sound crackles more as there's more bright stuff on the screen, less when it's darker colours.

Any ideas what to do now?

[tom66]

Re: Finlux 32FLD760P with Vestel 17PW20.v1

Mkay.

Red circled device: Measure voltage across. Care high voltage, nearly 400V.

Blue circled connector: While functioning and malfunctioning, voltage on each pin relative to the chassis. Use DC 200V.

[Serkai]

Re: Finlux 32FLD760P with Vestel 17PW20.v1

Not sure if it makes a difference, but all the problems started occuring more after I put the back cover back on in hopes of being done with the repairs?

Also, the one in red circles, measure voltage across means from the plus to minus on the cap? Sorry might be a little lost in translations sometimes.

[tom66]

Re: Finlux 32FLD760P with Vestel 17PW20.v1

Yes, measure voltage from positive to negative side.

[Serkai]

Re: Finlux 32FLD760P with Vestel 17PW20.v1

Okay. I just did that, standby is 319~320v, and when tv is on it's ~330v. Going about to check the pins now. Tv is hot as hell on the backside, probably heat sensitive.

When the tv screen gets stuck all bright and weird, it measures ~335v.

I'm not sure the DMM is completely accurate, but I did change battery in it to a brand new one and tested it on smaller batteries to check which was fine.

Edit. Corrected values after another check, must've held the pins badly.

[tom66]

Re: Finlux 32FLD760P with Vestel 17PW20.v1

385V is fine for PFC. Check that it's stable as the TV starts encountering more issues.
You clearly have 220VAC instead of 240VAC in UK -- that can make a big difference if PFC fails...

[Serkai]

Re: Finlux 32FLD760P with Vestel 17PW20.v1

Here's the values, measured as good as I can so I hope I didn't miss anything.

These are unplugged tv being plugged then power on, but not starting it completely. Next is tv on, watch some, then standby on remote. And last is tv on while being watchable, except when it went all weird once.

If I haven't written any values then I either missed the pin or I couldn't measure anything else than 0 on it.

[tom66]

Re: Finlux 32FLD760P with Vestel 17PW20.v1

22V should measure 24V and it's important for audio and backlight on this chassis. 10.8V should be 12V and that is used for t-con power and some other audio functionality. Check PFC voltage again. Otherwise, I'd just swap the PSU to be honest...

[Serkai]

Re: Finlux 32FLD760P with Vestel 17PW20.v1

Check PFC voltage again.

Sorry, I blame the late hour but which one was PFC again? All of them or anyone in perticular? What would make the voltage to drop from 24 to 22?

[tom66]

Re: Finlux 32FLD760P with Vestel 17PW20.v1

Main cap voltage.

Lots of reasons on this PSU... those 15n caps, leaky transistor, bad PFC voltage, bad output capacitor... This is why I do not repair them any more I just swap them. You will likely end up spending more in spare parts.

[Serkai]

Re: Finlux 32FLD760P with Vestel 17PW20.v1

Now that it's been on a while it's down to 21.3v, pretty sure of it. Would that even work? I get picture, but it's on the verge of flickering.

Main cap is still 333v when on and working.

[tom66]

Re: Finlux 32FLD760P with Vestel 17PW20.v1

Main cap at 333V is too low. You said 385V before? 21V is not enough to run a backlight well. 23V to 26V rated.

[Serkai]

Re: Finlux 32FLD760P with Vestel 17PW20.v1

Yeah I think I didn't hold the pins firm enough, it's definitely not 385v, now that I'm not as scared anymore I'm not shaking as much haha.

Just measured one more time now to be sure, tv on and working, 333v on main cap. Sorry for the mistake.

[tom66]

Re: Finlux 32FLD760P with Vestel 17PW20.v1

So like common fault on this set, PFC is not working, sadly, I do not know for sure why.
You are right to be scared as 400V can be extremely hazardous to one's personal well being.

[Serkai]

Re: Finlux 32FLD760P with Vestel 17PW20.v1

Damn. Crappy news is, there's no PSU's anywhere in sweden to buy, so with the shipping it's nearly double price for me to buy one.

What exactly is the PFC? I read it's transistors or diodes, or whatever it was somewhere. Is it plugged in before the main cap?

What I'm trying to get to is if it's traceable to where the fault may be. I think it's related to heat, because the tv acts much worse when the back cover is on and it's also much warmer when it is, now that it's off it's actually running pretty good.

[tom66]

Re: Finlux 32FLD760P with Vestel 17PW20.v1

You can try heating up parts of the PSU with a hairdryer to locate the fault.

17PW15-9 is a compatible replacement and easier to acquire in many instances.