LG 37LF66 - Pic goes off

[Turnip]

Hi folks,

Have one where picture flashes off esp when set is warm - Sound/backlight continues. Had look on Ebay for an SSB, noticed an ad for SM caps to cure the problem.

Anyone know which caps to replace ? - Thanks - Chris.

[bonesy]

Hi bud,I think this set has the long thin power board,one of the electrolytic s on the top right hand side causes  inter pictures,either the bottom or second from bottom cap,I think may be a 620 or 820,may not be domed,just dropped in value,that Jordan fella will know for sure.

[downunder]

Hi Chris,

Ohms Supplies have a kit, but it's for no picture when cold and intermittent hor lines, so I'm not sure if it applies to your symptoms.

It includes C901, C945, C533, C970, C975, C915. Doesn't sound like a cap problem though.

Don't suppose it's got a FAN1507A33 3V3 reg on the main board. That can give slightly lower output after 15 minutes or so, resulting in NP, SOK, BL OK.

Bruce

[michael first]

Hi, Chris & Bruce

but if it's the same old story of bad inductors on the main board,of which TV Tony gave a cure some years ago?

[bonesy]

With the cap in the psu faulty,set comes on & works as normal,but picture goes off with scene changes,if it's that it's a quick fix.Had it a few times.Normally when the regulator & smd caps on ssb play up,picture breaks up into lines first,followed by blank screen!Normally will come back on if frozen.

[Turnip]

Hi folks and thanks for your thoughts,

Had another look at that Ebay site and attach info-

On YouTube - noticed an American chum who removes surface mount electrolytics cold just by twisting the case, where seems no track damage.

I always heat one side at a time and lift gently, but I've still lifted a track or two which is a bit of a pain, so bought some cheap tweezers that got incredibly hot but didn't have enough heat reserve to melt solder on normal telly panels - Chris.

[bonesy]

Are they the symptoms that your set is showing,that are listed on the sheet,or does your picture just go off ?If it starts with lines on picture/jumping/breaking up before going off,then regulator i.c. &  caps in kit.There was a mod for removing a number of smd chokes & replacing with wire links,there is an official lg mod sheet for this,sadly I don't have it,but I'm sure someone will have it.It cures all sorts of faults.

[tv tony]

While since Iv'e scanned on here. Will upload it, if it still exists!

[tv tony]

Well, it's still on the site, I'm amazed!
Remove L911, L912, L918 and L919 and bridge them. These were called ceratech filters and it was in fact me who discoverd this problem. At the time we did warranty work for LG. Many years ago. This was an official repair OK'd by LG and there was a bulletin at the time. But after looking at the circuit it all came back. The old Alzheimers hasn't finished me yet.

[tv tony]

Sorry, found it, hope it sorts you.

[Turnip]

Hi folks, and thanks for the help.

Whipped out the Ceretechs and replaced with links (Must get some zero ohm chips, as tiny wire links are a pain)
Set went off again, and of course it was IC900 the 3.5v reg as folks suggested, as a squirt of freezer sorted it for a while.
Surprised to find that 'High Street' - Wiltsgrove, do packs of five for less than 3 quid post paid.
Thanks again - Chris.