42lv5400-ub no display but turns on.

[Serge 125]

Hi all!!!

Ok my 42lv5400-ub just decided that it doesn't show any pictures and yes I have done the flashlight test and don't see any thing on screen as for sound I don't know. It was working just a few mins ago and now nothing. I did noticed that when I turn it on I get a red led then I get 2 white flashing BUT the thing is that I found out that the TV is on because I can turn it off and I get the normal white led that turns on and off when the tv shuts down. So I didn't get the chance to test anything it happened late last night but I did took the time to take the back off for later today after work to check things out. I will try my T-CON power test thing to see if my lcd works with red, green, blue and white screen appearing. Still I'm asking anyone here for any advice so when I get back from work to test some of your suggestions and yes I do have the repair manual for it too. I do have a meter and a LED back light tester too. So thanks for any advice!!!!

THANKS in advance

Serge

 

[Nigel Goodwin]

Presumably the two flashes is an error code?, and any 'decent' make tends to shut the screen down totally if there's an error condition detected - which could be why the torch trick doesn't work. There doesn't seem to be any list of error codes in the manual, but that is unfortunately fairly common.

A quick google finds mentions of reflowing the BGA chip on the main board, for a multitude of problems, usually by putting the entire board in an oven.

 

[Serge 125]

Hey THANKS for the quick reply!!! Yeah I did have video problems with that chip about a year ago but if this is the problem again then it went to another level. I have my Quick 861 air station so I’ll give it a good heat up “again” but I know it’s just a temporary fix, reballing would be the best thing to do but don’t have the stencil to put soldering paste on it. So later I’ll give it a good heat up again and check and if it works I’ll be my 3rd time reflowing that chip. As for sound I couldn’t check because I can’t see the input menu on the screen but I’m confident that it works. Ok will let you know how it went. Again thank!!!

 

[Serge 125]

Hi all!!

Ok reflowed yesterday and all is well (again) but like I said reballing is the answer to this problem. When I had to reflow I hade video problems (pic) but this time the screen was black no backlight at all BUT when I did the T-CON screen test (modding the T-CON for this) and it didn't work so this was an indication that the backlight was in protective mode. Gee just a chip can cause many problems. BTW THANKS again for your help next time i'll know better!! ;-)