LG 60PB5600 - No picture

[mtb604]

Re: LG 60PB5600 - No picture

So should I just replace those four IGBTs and then reinstall the board and see if it works?

[Hamie]

Re: LG 60PB5600 - No picture

Id check to make sure that the short between vs input and ground is gone.

[mtb604]

Re: LG 60PB5600 - No picture

I tested them off board and on board- no short.
I installed the board and plugged in the TV and the IGBTs shorted immediately.
What did I miss?

[mtb604]

Re: LG 60PB5600 - No picture

Is this a lost cause or should I keep trying to find the fault?
What do you recommend I try next?

[mtb604]

Re: LG 60PB5600 - No picture

Might the buffers be shorting out the y-sus board?

[mtb604]

Re: LG 60PB5600 - No picture

Should I replace the buffers and then replace the IGBTs again?

[Hamie]

Re: LG 60PB5600 - No picture

OK let's try again, but this time please don't rush ahead and install boards before its been tested.

To answer your question this TV does suffer form faulty buffers so it's very possible that the buffers are taking out the sustain board.

Firstly take a picture of the top side of the y-sustain.

[mtb604]

Re: LG 60PB5600 - No picture

Thanks for sticking with me!
Here is the top of the Y-Sus board.

[Hamie]

Re: LG 60PB5600 - No picture

So put your meter in ohm range.

And check the resistance between the pins vs and gnd.
On this connector here.

Black probe ground, Red probe either of the vs pins.

Post back your reading.

[Hamie]

Re: LG 60PB5600 - No picture

Pic

[mtb604]

Re: LG 60PB5600 - No picture

I got 9 K-ohms across VS and ground at the P130 connector

[Hamie]

Re: LG 60PB5600 - No picture

That seems about right.
Try running the tv with both the buffers disconnected.

Does it stay on?

[mtb604]

Re: LG 60PB5600 - No picture

No. The four IGBTs I replaced are all shorted so the TV will not stay on with the Y-Sus board connected.

[Hamie]

Re: LG 60PB5600 - No picture

in my experience if any of those IGBTs are shorted you shouldnt get anything like 9k ohms between vs and ground. it would be far lower.

[mtb604]

Re: LG 60PB5600 - No picture

Well, crap. I connected the y-sus board to the P130 connector and the P100 ribbon cable. There were pops and flashes in the vicinity of the IGBTs and smoke from the vicinity of the logic board.

After I disconnected the power and waited for the caps to discharge, I measured the resistance across VS and ground at the P130 connector and now I get 0 ohms.

[mtb604]

Re: LG 60PB5600 - No picture

Is it beyond repair now?

[civiliandave]

Re: LG 60PB5600 - No picture

Not trying to jack your thread, I just have the exact same TV that is power cycling and I'm interested to see how you do. Or maybe one of us will have some parts for the other...

[mtb604]

Re: LG 60PB5600 - No picture

Hi Civilandave- check the youtube videos on ShopJimmy.com. I seem to remember that issue was addressed in one of their repair videos. If the problem turns out to be a bad y-sus board, I have not been able to find any replacement boards, but ShopJimmy has a repair kit to replace the transistors and resistors if you are comfortable soldering the components.

[mtb604]

Re: LG 60PB5600 - No picture

So is this still repairable or did I completely fry it this time?

[mtb604]

Re: LG 60PB5600 - No picture

Is there any way to check the logic board?