LG 42 PN4500 abnormal picture

[P.R.Gore]

Hi,
LG plasma tv ; model number 42PN4500 is showing picture with enormous number of black spots or say patches. All voltages that mentioned on panel steaker seem normal.(Vsus & Vad ). Please observe attached photos & suggest solution.
Regards
P R Gore

[downunder]

Looks like a faulty Z-Sus to me.

You could disconnect the flexi from the main board to the control board (under the PSU). At probably around 4 o'clock position on the big chip on the control, you should find the auto gen test points - could be marked R51/R52. Short these out and check the test patterns. If OK, main board is faulty.
If not, probably Z-Sus.                       Bruce

[P.R.Gore]

 Bruce,
As per your suggestion I connected jumper, the same fault appears in test pattern also. So fault should be in Zsus board. Can Zsus be repaired at component level ? Any repair hint?
Thank you very much for this repair suggestion! Waiting for your further reply.
P R Gore.

[downunder]

 No specifics, just to check FETs and Diodes for shorts and dry joints.     - Bruce

[P.R.Gore]

Ok. I will check & update.
Thanks.

[tv tony]

Doesn't quite look Z-sus to me. Hard to tell from camera shots but it looks to have plenty of brightness to it.

[P.R.Gore]

I throughly checked Zsus board but could not find any def
ective igbt or fet,I also I tried by replacment of electrolytic
Capacitors. But problem remains same.

[downunder]

Might be time to move to the Y-SUS. Do Vs and Va match the values printed on the panel label?

On the Y-SUS check D515 and fuse FS501, and resolder the adjacent transformer.                                Bruce

[P.R.Gore]

Thanks Bruce,
This set is still pending at my workshop, I will check as per your suggestion & revert.
P R Gore