LG 42PT353 Z-sus fault

[Trevtron]

This is a much younger set than the one in my last thread (funeral to be held later), this 42" plasma packed up almost 3 years old to the day. It belongs to a retired couple, good friends, and I rather embarrasingly recommended it at the time!

Apparently after a couple of slow start-ups, it wouldn't come on at all. I could hear the tell-tale whines from the PSU, so I took it away for a better look.

Soon discovered a short on the Z-sus panel (EAX620B1001), turns out to be o/p transistor Q6. It's a 30F124, one of a pair- the other measures OK passively.

It it normal for these to fail or could we be looking at something causing it?

TIA.

[sordids999]

Re: LG 42PT353 Z-sus fault

Posting pictures of the back of your tv showing the boards with clear pictures may help you more with fixing your problem

[Trevtron]

Re: LG 42PT353 Z-sus fault

Posting pictures of the back of your tv showing the boards with clear pictures may help you more with fixing your problem

Tried to upload pic's earlier without success- worked first time this morning!



And here's one of the Z-sus board, showing here the shorted IGBT was removed from.

[hannesmen]

Re: LG 42PT353 Z-sus fault

Hello Gentlemen and Experts :-)

I found this great forum and hope that maybe some of the experts can give me a hint.

I have a similar problem. When I turn on the TV it begins to start. I can see it because the red light turn offs. After a few seconds I can hear a sort of a fizzling (not a clicking) and then the red light turns on again. Obviously the TV recognizes a problem and starts the protection mode why the TV goes back into the stand-by mode.

I could locate the fizzling on the Z-sus board. Could this fizzling be an indicator for a problem on the board?
I checked the board but can't see suspicious indicators that some part did break.

Did anyone faced already a similar problem and could fix it?
Does it make sense to replace the whole board on purpose for $80?
Or does it make sense to start to replace single parts?

Well, would be happy if someone could give me hint.
Thanks to everyone.

Regards
Hannesmen

[hannesmen]

Re: LG 42PT353 Z-sus fault

Hi Folks

After reading many posts I'm some steps further.

After disconnecting the ZSUS board the TV seems to work again, of course without a picture. But I can turn on the TV and it is communicating with the remote control. And I can turn off the TV again.

I disassembled the board and measured the resistance between VS and GND and got readings between 2 and 5 ohms. I'm really sure but due to my understanding this means a short on the board???

As the YSUS bord is connected from the ZSUS I'm still not sure which of the boards is faulty.
I did also a measurement on the YSUS board between VS and GND and got readings like 0,000 MOhms or 0,580 MOhms what should indicate no short???

Anyway, I'm still not sure about the ZSUS. Is my assumption about the short on the ZSUS, right?
Does it make sense to replace the whole board on purpose?
Or does it make sense to start to replace single parts?

Thx & Regards
Hannesmen

[hannesmen]

Re: LG 42PT353 Z-sus fault

Hi experts,

does anyone has an input? I don't want to open a new thread as this one fits perfectly?



Regards
Hannesmen

[saud52]

Re: LG 42PT353 Z-sus fault

Dear!
replace the following parts : Q6/Q9 = 30F124 and IC//IC8 = FAN73711

[buchman]

Re: LG 42PT353 Z-sus fault

[QUOTE=
Soon discovered a short on the Z-sus panel (EAX620B1001), turns out to be o/p transistor Q6. It's a 30F124, one of a pair- the other measures OK passively.
TIA.[/QUOTE]

How did you discover the short? what tests did you make?

[chrle]

Re: LG 42PT353 Z-sus fault

I have same model of tv,i changed Q6/Q9 = 30F124 on zsus and ysus and diodes rd2004ln and rg2006, but no ic fan73711.

ysus not connected ---> tv turn on ,tcon blinking green
when i connect ysus then get blown Q6/Q9 = 30F124 and diodes RD2004ln 2pc

could be problem in ic fan73711?

[chrle]

Re: LG 42PT353 Z-sus fault

update:

Z-sus keep blowing 30f124 2x and rd2004 x2 ysus not connected


when z-sus is not connected ,just -Ysus tv turn on without picture and stays on.

I chane IC 7 ,IC8,and 30f124 2x ,rd2004 x2 after trurn on keep blowing .

[chrle]

Re: LG 42PT353 Z-sus fault

update:

Z-sus keep blowing 30f124 2x and rd2004 x2 ysus not connected


when z-sus is not connected ,just -Ysus tv turn on without picture and stays on.

I chane IC 7 ,IC8,and 30f124 2x ,rd2004 x2 after trurn on keep blowing .

I find ZD2 shorted

[chrle]

Re: LG 42PT353 Z-sus fault

I find ZD2 shorted

anybody know values for this zener diode?

[chrle]

Re: LG 42PT353 Z-sus fault

ok guys ,I have VS shorted to ground on Y-sus board,I changed all diodes and igbt transistors and ic fan73711 and it is still VS shorted to ground.

what to test?

[DarkoOhrid]

Re: LG 42PT353 Z-sus fault

anybody know values for this zener diode?

I have the same problem with this Z sus board.Did you find a value of zener diode ZD2?

[DarkoOhrid]

Re: LG 42PT353 Z-sus fault

Can anybody tell what is the value of ZD2?!