LG 26LC55 -- Freezing, slow to boot up

[tom66]

Thought I would post this as me and Sienoki dealing with it currently.

Found that it would take 15 mins or so to start up sometimes, the screen would fade or have random lines on it.

Found one cap on main board 100uF 16V, with 6.8 ohm ESR, for a 5V to 3.3V regulator. Regulator had 100mVp-p oscillation on the output. So cap will be replaced and we will try it out. Otherwise, I suspect t-con or BGA cracking.

[kevinm34232]

Re: LG 26LC55 -- Freezing, slow to boot up

Tom I had a LG 26LG30-UA that did almost same thing. After about 15 mins picture would be normal but before that it would have half the screen or a frozen screen, different weird things. I played with freeze spray and a hair dryer and it seemed like it was the T-con board, but after replacing it, it did the same thing. Never fixed it, thought maybe bad VPU on main board..?

[tom66]

Re: LG 26LC55 -- Freezing, slow to boot up

Cap didn't fix it, it appears. The regulator may be at fault itself, or we may be chasing a wild goose...

Regarding T-con I -think- it's the T-con due to it fading in slowly. That just doesn't happen with a main board. But repairability will depend on the T-con price. It has a Chi-Mei panel in it.

[ben7]

Re: LG 26LC55 -- Freezing, slow to boot up

Cap didn't fix it, it appears. The regulator may be at fault itself, or we may be chasing a wild goose...

Regarding T-con I -think- it's the T-con due to it fading in slowly. That just doesn't happen with a main board. But repairability will depend on the T-con price. It has a Chi-Mei panel in it.

Does the EEPROM (if it has one) run off that 3.3v? It could be corrupt. I have seen corrupt EEPROM's make the screen fade and/or show random junk.

[tom66]

Re: LG 26LC55 -- Freezing, slow to boot up

Quite possibly, something to look at, thanks.

[Rtech]

Re: LG 26LC55 -- Freezing, slow to boot up

Lo and behold,I have exactly the same...turns on and works well sometimes,other times rubbish on the screen,until it has been on a while, then bursts into life.

[tom66]

Re: LG 26LC55 -- Freezing, slow to boot up

It's a bad panel. I'll bet you've got a Chi-Mei LCD in yours. Anyway, it is the top left tab. It is fixable, but I don't know how long it will last. Encountered the same thing in a Panasonic LCD with a Chi-Mei panel.

If you take the TV upright on its stand, and just carefully twist it left to right or right to left (flex the plastic case) and the picture comes right immediately, you know it's the tab bond issue.

[Behemot]

Re: LG 26LC55 -- Freezing, slow to boot up

I have the same TV with same problem - problematic start unitl it was only grey. I've disassembled the display and tried pushing the flex cables while in operation, no change. I do not think the problem is flex cables, but either something on the flex board, or something else.

TCon seems to be somewhat working, I have also 26LC41 with blown fuse on TCon. I tried the 26LC41 with TCon from 26LC55 and it displays, however it is somewhat blue and otherwise strange.. But the TCons are slightly different, either it is that, or the 26LC55 TCon itself is bad. Will try swapping the displays as soon as I get the 26LC41 TCon working (need 2A SMD fuse).

[nomoresonys]

Re: LG 26LC55 -- Freezing, slow to boot up

Very nice, fast accurate diagnosis Tom, that flex screen method can sure save a lot of time and money, from people wrongly throwing boards at it.

[Behemot]

Re: LG 26LC55 -- Freezing, slow to boot up

The TCon from 24LC41 burned another fuse, there must be some problem on it. The rail goes to several places incl. BGA chip Maxim 8728E which claims to be all-in-one multi-votlage output controller.

As it did not burn the other TCon boards fuse (though colors were bad, hopefully due to their difference), I think there is problem somewhere on this TCon. It makes sense the Maxim chip has burned to short internally. It is V260B1-C03, I can get repalcement ones for some 20 bucks so I think it is better than messing with this one…