Lg 50" plasma no picture but sound

[johnjgjohn]

Hi everyone got a 50" lg plasma here which powers up but no picture i have sound ive checked all boltages coming from psu and they seem fine. On the zsus the 18v is only measuring 3 volts and same with ysus disconnected the board is eax65335001 can anyone help narrow down where the 18v has gone thanks

[johnjgjohn]

Re: Lg 50" plasma no picture but sound

Is there any plasma experts online

[Hamie]

Re: Lg 50" plasma no picture but sound

Take a picture of the y-sustain please.

[ReeceyBurger123]

Re: Lg 50" plasma no picture but sound

Probably shorted Ipm but we need images.

[johnjgjohn]

Re: Lg 50" plasma no picture but sound

All the voltages are fine going from psu to zsus but the power cable that connects the ysus the 18v is only goving me 3v with or without the ysus plugged in

[johnjgjohn]

Re: Lg 50" plasma no picture but sound

This is zsus

[johnjgjohn]

Re: Lg 50" plasma no picture but sound

This is ysus

[johnjgjohn]

Re: Lg 50" plasma no picture but sound

I bought brand new zsus as thats the board i wasnt getting the 18v from but new board is doing same thing is there a signal that has to come from logic board or somewhere to switch on 18v to power ysus?

[johnjgjohn]

Re: Lg 50" plasma no picture but sound

Any idea reecey

[Hamie]

Re: Lg 50" plasma no picture but sound

You have a faulty y-sustain.
This TV is quite difficult to troubleshoot because a failed y-sustain pulls down all the other voltages.

Is there a green flashing led on the control board?

[johnjgjohn]

Re: Lg 50" plasma no picture but sound

No green flashing light , but surely if the ysus was at fault i would still get the 18v supply leaving the zsus to feed ysus? With the ysus disconnected

[Hamie]

Re: Lg 50" plasma no picture but sound

Nope, everything has to be working perfectly for this TV to show perfect voltages. It's a pain in the arse.

It's almost certainly a failed y-sus.

Don't know why LG decided to leave their trusted y-sustain and buffer layout and copy the more recent Panasonic SC boards.

Take a close up picture of the lower half of the y-sustain, I probably know what's failed.

[johnjgjohn]

Re: Lg 50" plasma no picture but sound

Lower half

[johnjgjohn]

Re: Lg 50" plasma no picture but sound

Top half

[Hamie]

Re: Lg 50" plasma no picture but sound

OK you see the 3 resistors.
First one is 2.2 ohm (red red gold gold)

Bend them up towards the capacitors and take a photo of the surface mount components below.

[johnjgjohn]

Re: Lg 50" plasma no picture but sound

Better pic of lower half ysus

[johnjgjohn]

Re: Lg 50" plasma no picture but sound

Like this?

[Hamie]

Re: Lg 50" plasma no picture but sound

Yeah there should be a surface mount capacitor under the 2.2 ohm one, it will be under the glue. Scrape the glue away.

[johnjgjohn]

Re: Lg 50" plasma no picture but sound

Yeh there is

[Hamie]

Re: Lg 50" plasma no picture but sound

Put your meter in ohm range and measure across it.