LG 60PV400 display problems

[ducatilover]

Background on the set: Picked this set up from someone who was going to throw it away because it stopped working. Took it apart and checked PS for proper voltage and it checks out ok. It had no picture but had sound. After reading a few threads on here I reflowed the inductors on both Y and Z boards and now I have picture ONLY when the Z board is disconnected. The picture looks dim and somewhat fuzzy and has black blotches on the screen that slowly fade as the screen warms up. If I plug in the Z board then the tv will try to power on but shut down. I also hear a electrical buzzing sound from the Z board when it tries to power up.

Can anyone help troubleshoot this board or help bring this set back to life? I looked online for a replacement board and cant find one. Ill post some pics and video (if possible) of the boards and powering up of the set.

Thanks

[KevinCro]

Re: LG 60PV400 display problems

Sounds like a fault in the z board. Check to see if the mosfets are shorted. Use a multimeter on continuity setting and see if you get a beep between the pins. Also check the three resistors grouped together on the right side of the board and make sure they read correctly. I had a zsus that blew and had several resistors in a row that were blown.

[ducatilover]

Re: LG 60PV400 display problems

checked the fets as you said and posted a picture of where I have continuity. The red indicated where the continuity was. Some were only on two points others on all three. The resistors on the right where checked for continuity also and the first one did not make a sound. The other two did.

Not much of a electronic intelectual but I can check voltages, resistance, etc. Let me know what you think.

[tom66]

Re: LG 60PV400 display problems

It would appear you have a lot of failed devices. It would be good to remove all the "Q" labelled devices (e.g. Q123, Q456...) and check them out of circuit for shorts.