LG 60PZ570-TB only stays on for 5 seconds

[nimble87]

Hi All,

My 60 inch LG 60PZ570-TB decided to turn itself off the other day. It now clicks once and then clicks again 5 seconds later shutting it off. I researched it a lot and purchased a replacement C802 1.6kV capacitor. The original one had bulged a little bit, unfortunately the new capacitor made no difference.

I'm now stuck as to what to do next. I'm still learning when it comes to these things, but like everything else i've pulled apart i'll have a crack at anything.

PCB: EAX63330001/11
PSU P/N: EAY62171201

After reading a few posts I'm thinking it could be the voltage regulator, that's a stab in the dark for me. I managed to find this kit, thinking it may fix the problem.

http://www.shopjimmy.com/lg-eay62171...repair-kit.htm

Any help would be greatly appreciated, thanks in advance.

Cheers

[CapLeaker]

Re: LG 60PZ570-TB only stays on for 5 seconds

Here is what we need to know. There is a ribbon cable from the PSU going to the main board you have to check with your DMM. Write all those voltages down with their corresponding pin out, with the tv on and the same thing when the tv acted up.

[nimble87]

Re: LG 60PZ570-TB only stays on for 5 seconds

Thanks for the reply Capleaker, I'll give it a shot tonight after work and post the results.

Cheers

[nimble87]

Re: LG 60PZ570-TB only stays on for 5 seconds

Just took some readings on the pin outs on the power supply board, they are as follows:

Incoming mains = 248v

YSUS and ZSUS had exactly the same outputs
VS=203v
VA=starts at 53v drops to 46v then shuts off
Mv5=5.2v

Pin out to ctrl=5.2v

I had a bit of a play to try and eliminate different boards, the only thing I found was that wen I disconnect the YSUS and ZSUS the TV will stay on with sound only This is the only time I've managed to get the tv to stay on.

Cheers.

[tom66]

Re: LG 60PZ570-TB only stays on for 5 seconds

So, with Y-SUS and Z-SUS connected it clicks off immediately?
What is Vsus with them connected?

[nimble87]

Re: LG 60PZ570-TB only stays on for 5 seconds

So, with Y-SUS and Z-SUS connected it clicks off immediately?
What is Vsus with them connected?

With both YSUS and ZSUS connected it will click once when powering on and then click again roughly 5 seconds later when it shuts it self off.

Sorry I'm very new to this, I'm guessing you mean the voltage at Vs test point while connected? It's 203v

[tom66]

Re: LG 60PZ570-TB only stays on for 5 seconds

So you get 203V with both boards connected but it still clicks off?
Weird. Can you try with just the Z-sus removed?

[nimble87]

Re: LG 60PZ570-TB only stays on for 5 seconds

Yes that's correct.

Just the ZSUS removed VS test point reads 203v then shuts off

Just the YSUS removed does exactly the same reding 203v

With both YSUS and ZSUS removed tv stays on with only sound and no picture. Vs test point reads 203v and Va test point reads 54.9v while tv is running.

[tom66]

Re: LG 60PZ570-TB only stays on for 5 seconds

Does Va read 55V with boards connected?

[nimble87]

Re: LG 60PZ570-TB only stays on for 5 seconds

Does Va read 55V with boards connected?

Va is 53v when powered on then drops to 46v a few seconds later as the tv shuts off. That's with both boards connected.

[tom66]

Re: LG 60PZ570-TB only stays on for 5 seconds

OK, not a panel short then, that's good.
With the boards removed, does the LED on the control board blink at all?

[nimble87]

Re: LG 60PZ570-TB only stays on for 5 seconds

With both boards removed the control board LED flashes green. Two long flashes, followed by two shorter flashes

[tom66]

Re: LG 60PZ570-TB only stays on for 5 seconds

Well, it's not a control board fault then.
Baffling - not really sure what to suggest.
Could be a short on one board - but seems to affect both?
No cracks/damage to the panel?

[nimble87]

Re: LG 60PZ570-TB only stays on for 5 seconds

It's got me stumped, could it be that something on the YSUS and ZSUS failed at the same time? The panel is all good.

The shut off time seems to vary a little bit depending on how long I leave the tv off. Sometimes I can get a glimpse of the picture before it turns itself off, it seems like it's very close to staying on. Randomly before it stayed on for around 5 minutes with picture and sound working and then it failed again. Haven't been able to reproduce that result again.

[nimble87]

Re: LG 60PZ570-TB only stays on for 5 seconds

It wouldn't be the new C802 capacitor causing the problem would it? The output voltages would be wrong if this had failed, correct?

Thanks very much for all the effort you're putting in, greatly appreciated.

[tom66]

Re: LG 60PZ570-TB only stays on for 5 seconds

Hm, wouldn't be a short if it worked like that, maybe it is a misbehaving mainboard.

Try this:-
Disconnect the LVDS cable between the main board and control board. This is the only ribbon cable that runs between the two boards. The main board has the HDMI ports on it; the control board has the blinking LED.

Disconnect the power cable between the power board and main board.

Put a jumper across the EXT AUTO GEN test points.

Plug the TV in, do you get test patterns on the display?

If so - replace main board
If not - we may need to jumper power board connections to be sure

[nimble87]

Re: LG 60PZ570-TB only stays on for 5 seconds

Can't seem to locate the EXT AUTO GEN test points. Are these on the control board?

[ReeceyBurger123]

Re: LG 60PZ570-TB only stays on for 5 seconds

Checked Pson and Vs on signals at the mainboard generates ?

[tom66]

Re: LG 60PZ570-TB only stays on for 5 seconds

AUTO GEN not marked, but it's the two holes next to R51,R52. These need to be shorted together.

[nimble87]

Re: LG 60PZ570-TB only stays on for 5 seconds

Ok so just had a quick test this morning.

The first time it powered on it flashed a red screen and turned off, 2nd try did the same, 3rd it stayed on and went red, then green, then blue and then sweeping gray color from each direction and then switched off.