LG 42LC46-ZC picture off sound ok

[vinceroger69]

Re: LG 42LC46-ZC picture off sound ok

just to clarify so when your saying the picture goes off is the white backlight still on and it just the picture thats goes off

[Jimbo555]

Re: LG 42LC46-ZC picture off sound ok

Ok. Voltage on T-Con Fuse. TV working OK. 12v one side and 12.01v the other. TV picture off and sound Ok. 12v one side 11.98 the other. Yes only the picture goes and the backlight is on.

[vinceroger69]

Re: LG 42LC46-ZC picture off sound ok

im not sure what else to suggest to test maybe budm with have a glance at your thread and have some suggestions, seems odd you have the same fault with two diffrent tcon boards on the tcon the large square gamma chip whats the details on it?

[Jimbo555]

Re: LG 42LC46-ZC picture off sound ok

Thanks for the replies. Then chip details are:- LG Philips LCD, R8RD 1028 FP, 01H1L - D068A, 705108

[vinceroger69]

Re: LG 42LC46-ZC picture off sound ok

on the tcon i can see a few gold test points vgl vgh etc etc maybe worth checking these to see if any alter when the picture goes of black probe on tv chassis again

[Jimbo555]

Re: LG 42LC46-ZC picture off sound ok

Thanks Vinceroger. Tried the test as you suggest. Around that area I only get voltage on the vgl which is 6.01v. The other two read as 1. It has to be something else as I have tried another T-Con board today. Could there be a loose joint to the CCFL tubes.

[vinceroger69]

Re: LG 42LC46-ZC picture off sound ok

but if you say the backligts stays on that means the ccfl are working as far as i know its the tcon etc that put the picture into the lcd i maybe wrong someone will advise soon i hope what else you can try it dsont leave much now only the mainboard i guess

[Jimbo555]

Re: LG 42LC46-ZC picture off sound ok

Thanks for all your help Vinceroger. Will get to the bottom of it one day.

[Jimbo555]

Re: LG 42LC46-ZC picture off sound ok

On tips picked up from this site I nicked my wife's hair drier and a cooling fan. It seems to be the main board that is the problem. Using the hair dryer technique on the main board the picture goes off after three minutes. Putting the cooling fan on the picture returns after 20 seconds. Now i haven't been around the PSU board with the fans and as I have changed this board before I can safely rule it out.

Now on the main board I can only see one large capacitor and it is around this area I put the hair drier. Could this be the problem?

I am thinking of purchasing a replacement main board. But before I do has anyone any ideas of which component failure it could be?

[vinceroger69]

Re: LG 42LC46-ZC picture off sound ok

mainboards are hard to find the faults as some times its bga soldering etc you can try to isolate the area your heating i tend to use a empty toilet/kitchen roll cardboard tube and aim the heat down it to narrow down the sensitive area but yes the mainboard is certainly worth swapping next just make sure all sticker numbers etc match up.

[Jimbo555]

Re: LG 42LC46-ZC picture off sound ok

Solved and TV working again. Finished up buying a replacement Main Board for £30. Could not pinpoint the problem with the original. Thanks for all the help from the people on this site. I'll be back I'm sure.

[vinceroger69]

Re: LG 42LC46-ZC picture off sound ok

Glad you managed to fix the tv and another set saved from the landfill.