LOG26LW782 Logik LCD Display Fault

[D.R.]

Hi,

I have recently saved a Logik LCD TV from a trip the skip and I'm looking for some advice on how to rectify its fault.

When you switch it on it displays a grey screen for up to 20mins, depending on when it was last switched off, during which you get sound and can switch channels and after which it works perfectly. The grey screen fault can be as little as 3mins or no grey screen if its just been switched of then back on.

I was thinking it was a capacitor charge / discharge issue due to the variable grey screen time and rather too eagerly re-caped the PSU to no avail but after finding this great forum and reading several posts I am leaning towards a faulty T-Con board.

I'm also thinking it could even be a dry joint somewhere on the T-Con board, I'm not lucky enough for it to be a loose connector.

I cant find a service manual for the TV so if anyone can suggest places to look it would be appreciated. I can post pics if you think they will help and I'm an Electrical Engineer (but not a TV Eng) so feel free to suggest a place or two to poke around with a multimeter.

I've found a place selling the correct T-Con board for £35 but I'd rather fix it if at all possible.

[D.R.]

Re: LOG26LW782 Logik LCD Display Fault

PCB images attached and for what its worth a picture of a grey screen

I re-soldered a few dry looking joints on the main board and re assembled the TV and now I have a new and interesting fault to add. The TV still displays a grey screen and eventually powers up but now I have no sound and when you switch the TV into standby the standby LED constantly blinks on and off.

I'll pull it apart again to see if I've left a connector off... I guess the fault could be on the main board as the T-con is connected there.

Any thoughts?

[D.R.]

Re: LOG26LW782 Logik LCD Display Fault

Forget that last post, some idiot left off two connectors. Fault is as described in the original post.

[D.R.]

Re: LOG26LW782 Logik LCD Display Fault

The main board, part number 17MB22-2, appears to be common to a lot of TV's manufactured by several different companies I found a Vestel manual here not had a chance to take a really good look at it but it looks promising.

The T-con, part number V260B1-C01, also looks widely used with listings for new boards from China on e-bay.

[tom66]

Re: LOG26LW782 Logik LCD Display Fault

Ah! Vestel strikes again. More crap TVs from Turkey. (No offence intended to Turkish people, but Vestel suck.)

Check the cable going from the main board to the T-con. I had a TV where this was loose. The TV would power on but all the colours were messed up. When it warmed up, the colours would return to how they should be.

[D.R.]

Re: LOG26LW782 Logik LCD Display Fault

I've had it apart and put it back together being careful to make sure the T-Con was connected to the main board properly but no luck.

I will try carefuly wiggling the connector on the main board a bit with the set on but I cant get to the T-Con end as its under the main board with a steel frame in between.

I'm still guessing its a T-con problem as I have sound, anyone disagree or have any other thoughts?

[tom66]

Re: LOG26LW782 Logik LCD Display Fault

I've had it apart and put it back together being careful to make sure the T-Con was connected to the main board properly but no luck.

I will try carefuly wiggling the connector on the main board a bit with the set on but I cant get to the T-Con end as its under the main board with a steel frame in between.

I'm still guessing its a T-con problem as I have sound, anyone disagree or have any other thoughts?

Usually when you have sound, the T-con is at fault.

It could also be the connector, but it would seem you have ruled that out.

The frame is EMI shielding. The shield can be removed for testing but should be replaced when assembled.