Goodmans LD3265D (Vestel 17PW20.1) - sound but no picture at startup

[Taxman]

Hi

I am a new member. Having gratefully used the advice on this site to repair a TV and a DVD player, I am hoping that I can impinge on your knowledge to assist with identifying the source of this specific issue.

This is a tv that I rescued from a communal bin. It actually worked first time but ever since it has showed the faults that presumably led the previous owner to scrapping it.

1) On first starting up (from cold start or standby), there is normally sound but no picture. The picture appears after 10-20 minutes (I haven't timed it but I believe this time is getting longer) and will then stay on working perfectly until the tv is switched off.

2) On the odd occassions when the tv will start up properly first time, after a while it will usually slip into the 'no picture' mode as above with the picture returning after 10-20 minutes and staying on fine afterwards.

There is 1 related issue I've noticed that to my untrained mind seems somehow relevant. If I switch off when I've got no picture, I can see the screen flash a normal picture for a fraction of a second as it switches off.

In checking the boards, I had hoped to see the signs of bad caps but they all look fine - although that does not of course mean they are indeed fine.

All connections look good and I can't see any signs of dry or cold solders.

Can anyone tell me where they think I should look first? I know this is a fairly common problem so I'm hoping someone may be able to be specific about the most likely cause - specific caps perhaps?

I can provide the schematics if required. I cannot however do any testing or voltage checks etc as I have no such equipment. Nor can I replace all the caps as I don't have them, only a few individual caps to hand.

I can provide pictures later if required (too dark just now), although as I say I don't think there are any visible signs of damage anywhere.

[tom66]

Re: Goodmans LD3265D (Vestel 17PW20.1) - sound but no picture at startup

Ah, another Vestel. I've repaired this same one.

You can either replace the PSU,
or replace the two 15n capacitors near the transformer (common failure.)

I have had it with Vestel power supplies as there's usually a lot more wrong (or maybe I've just had bad luck??), I generally just swap the whole PSU out. It's available around £20 on eBay; also, 17PW15-9 is compatible and cheaper.

[Taxman]

Re: Goodmans LD3265D (Vestel 17PW20.1) - sound but no picture at startup

Tom66

Thanks for your input, much appreciated.

Can I ask you to be more specific though please about locating the 15n capacitors? Sorry - I cannot see anything showing with that sort of measurement but that is no doubt due to my lack of knowledge.

[tom66]

Re: Goodmans LD3265D (Vestel 17PW20.1) - sound but no picture at startup

Can you post a picture as they're always a different colour on every vestel I have seen.

[Taxman]

Re: Goodmans LD3265D (Vestel 17PW20.1) - sound but no picture at startup

I've posted 2 pictures in a vain attempt to make up for the bad light and shadows (it's dark here).

[Edit: added 3rd picture which may be clearer)

[tom66]

Re: Goodmans LD3265D (Vestel 17PW20.1) - sound but no picture at startup

It's those two long rectangular blue ones on the bottom right.

[Taxman]

Re: Goodmans LD3265D (Vestel 17PW20.1) - sound but no picture at startup

I saw previous posts referring to the same points on the board (C877/C878) but hadn't actually located them until Tom pointed it out - in my ignorance I was looking for cylindrical caps...

I don't have these caps to hand but will order some and will return to this thread in a few days to update my progress.

In the meantime, many thanks to Tom for his prompt and helpful advice.

[tom66]

Re: Goodmans LD3265D (Vestel 17PW20.1) - sound but no picture at startup

Likely same problem with the 26 inch Sanyo on this forum, as I said before to him:

The originals were insufficient just, 400V or 630V, depending on what was cheapest on the day. Use at least 800V, preferably 1000V. Transients are what kill these caps.

[Taxman]

Re: Goodmans LD3265D (Vestel 17PW20.1) - sound but no picture at startup

I think these caps are already 1,000 volts - both have '1KV' written on them which I assume means 1,000 volts.

Should I still be looking at replacing them?

[tom66]

Re: Goodmans LD3265D (Vestel 17PW20.1) - sound but no picture at startup

Good point. I am not sure. I do recall replacing the 1000V ones too. But I usually just swap the PSU.

[Taxman]

Re: Goodmans LD3265D (Vestel 17PW20.1) - sound but no picture at startup

Before I order new caps and start individually replacing them, do any of you good people have any further advice that might be relevant here?

Thanks again to Tom for his initial advice. I haven't yet replaced the suggested caps but will do so shortly - just wanted to check if anyone had anything else to add before I order them in.

Thanks all.

[tom66]

Re: Goodmans LD3265D (Vestel 17PW20.1) - sound but no picture at startup

I have recently repaired a Vestel and it wasn't those two caps. The voltage across the big 450V cap was just 340V instead of 392V, which was causing the TV to only intermittently run. If you have that problem it's a lot of components to replace (PFC failure), I just ended up swapping PSU. Not worth fiddling around...