LG50PG20D Plasma which not showing picture but has sound!

[wezzo]

Hi Guys,

First and foremost thank you for sharing such great knowledge..
i have been given an LG50PG20D Plasma which is not showing any picture but has sound!

I have researched quite a bit and have done some tests on the Plasma which are below.....

I have removed the cover and cleaned dust with compressed air.
All tests where completed with wrist strap.
Power up shows Red Standby LED on front panel
Green middle LED on control board.
When press power on Remote Green Front LED flashes 6 times and stays solid Green
Can scroll through inputs on remote and get dvd sound through to speakers
Fuse ok on PCB and heat syncs are all warm after 30 mins.
Fuse ok on ZSUS and heat syncs are all warm after 30 mins.
Fuse ok on YSUS but heat syncs are cold after 30 mins.
No bulging caps or signs of burnt smell.
The outputs of the Va & Vs are as follows... Va: 60 shows: 60.6 - Vs:194 shows: 194.5
Isolated PS and Have done a static load light bulb test on it for 15 min and all voltages good
I have isolated the Control board and checked FL111 and FL12 all good
I also connected 5v from power supply to IC121 pin 1 and all good as i can tell, middle lcd lights up.
Checked IC 121/151/171 and all seem fine
Checked 16v to ZSUS from pin 1 on P163 and all good
Then isolated Main PWD, shorted the auto test pins but no test pattern.


That's where I'm up to.
Does this mean its either of the Y/Z or X boards or Screen?

Any help would be greatly appreciated.

Thanks in advance.

[wezzo]

Re: LG50PG20D Plasma which not showing picture but has sound!

here are the pics of the boards while powered ...

[tom66]

Re: LG50PG20D Plasma which not showing picture but has sound!

On the back inner metal plate that all the circuit boards are mounted on, there should be a sticker, printed "MODEL: PDP50######" (or similar...) what is printed on yours?

[wezzo]

Re: LG50PG20D Plasma which not showing picture but has sound!

Hi Tom66, thank you for the quick reply, the Model no is PDP50G10343, attached are the pics of it.

[erskine]

Re: LG50PG20D Plasma which not showing picture but has sound!

hi Wezzo, had a similar set with the same problem , it wasthe ysus board

[wezzo]

Re: LG50PG20D Plasma which not showing picture but has sound!

Het Erskine, i am thinking that too but want to make sure its nothing else as well, how much was the YSUS to replace mate?

[wezzo]

Re: LG50PG20D Plasma which not showing picture but has sound!

Does anyone else think its the Y-SUS or know of a way to pinpoint it properly

[tom66]

Re: LG50PG20D Plasma which not showing picture but has sound!

50G1 in this document.


Check -Vy, Vsc per instructions.

[wezzo]

Re: LG50PG20D Plasma which not showing picture but has sound!

Thanks Tom, -Vy is -.2 and Vsc was 0
does that mean Ysus board has gone?

[wezzo]

Re: LG50PG20D Plasma which not showing picture but has sound!

i just had another look at the upper and lower buffer boards, i read somewhere that the correct way to disconnect them was from the Ysus board itself and not the panel, so i did that and...
Disconnecting the upper buffer with center cable attached = unrecognizable picture on top and white/grey screen on bottom which fades to dull grey
Disconnecting the upper buffer with centre cable pulled = only white/grey screen on bottom which fades to dull grey, heat sinks on upper buffer got extremely hot and YSus heatsinks got warm for the first time.
Disconnecting Lower Buffer with centre cable attached or pulled = NOTHING
i completely removed upper buffer and re tested the -Vy and Vsc and both fluctuate between 0 and 46v.
plugged a dvd player in and got a very garbled lower picture for a few seconds then tv switches into standby, turn tv back on and white/grey screen again, no garbled picture?
any suggestions anyone? Ysus plus upper Buffer??
any help would be awesome

[wezzo]

Re: LG50PG20D Plasma which not showing picture but has sound!

anyone please?

[wezzo]

Re: LG50PG20D Plasma which not showing picture but has sound!

could anyone please tell me if it is the Ysus board where i could purchase this from?

[tom66]

Re: LG50PG20D Plasma which not showing picture but has sound!

Does -Vy, Vsc appear if buffer disconnected? Y-sustain fuse good?

[wezzo]

Re: LG50PG20D Plasma which not showing picture but has sound!

thank you Tom,
-Vy and Vsc are the same with both buffer boards disconnected (reading fluctuate between 0 and 46v) Fuse is all good (measures 194.4 on both side and diode test with power off the continuity is good)

[tom66]

Re: LG50PG20D Plasma which not showing picture but has sound!

Bad Y-sustain with possibly buffer boards having damaged it, though that is rare nowadays.

[wezzo]

Re: LG50PG20D Plasma which not showing picture but has sound!

cool thank you again, should i get buffers as well do you think?

[wezzo]

Re: LG50PG20D Plasma which not showing picture but has sound!

i just checked the upper buffer and according to the lg 5050pg20 training slides the upper buffer is stuffed! but lower checked out ok

[HENFOR]

Re: LG50PG20D Plasma which not showing picture but has sound!

Disconnect the power from the mainboard the board down on the right hand side.

now short out the auto_gen with a peice of wire while tv unplugged.

after this process plug it in.
You should see a test pattern this will rule out Y-sus and Z-sus problems.

Problem will be main board

[rccrasher65]

Re: LG50PG20D Plasma which not showing picture but has sound!

i just checked the upper buffer and according to the lg 5050pg20 training slides the upper buffer is stuffed! but lower checked out ok

I had the same tv, mine was upper buffer board, please be careful removing ribbon cables I tore mine and ruined the set over a $19.00 board. shopJimmy. com great place for boards.

[gravybones2002]

Re: LG PDP50G10343 which not showing picture, at all

Hi guys

I have myself a LG PDP50G10343, I have had the same issue as the previous people on this forum and have also performed the same tests as everyone else, I still haven't gotten any success, I say my problem is pointing towards the main control board for the X and Y sustain (50G1A_CTRL) (EBR50038701) has anyone replaced this to fix the issue

Please help...... thanks