LG 60PZ570 main board failure?

[LGLover]

Hi all,

My plasma is playing up again. The ZSUS failed and was replaced 6 months ago but now I've had it fail again.

Symptoms: On power on, relay clicks but no picture. Pronounced buzzing from both SUS boards. Buzzing drops in pitch a few moments after power on. CTRL board diode is flashing three short one long ( . . . ______ )

See this video for buzzing and CTRL board diode flashing.

History: This is similar to what happened 6 months ago except it was the ZSUS only making the noise. Replacing it fixed the issue so the first thing I did this time was replace the YSUS. This didn't fix it.



Voltages:
VS = 203
VA = 54
YSUS VY = -180
YSUS VSC = 147
ZSUS VZB = 105

Troubleshooting: I've disconnected the upper, lower and both buffer boards. No change to buzzing from YSUS, no picture on upper/lower screen. I've disconnected ZSUS and YSUS boards, no change.

I bridged R51/R52 and disconnected P31 as shown here and the display powers on and shows test patterns.

This leads me to believe that the main CTRL board has failed but I wanted to get a second opinion before I spend any more money.

My experience in these kinds of things is rudimentary but I'm hesistant to hand it over to the shop until I've done all I can.

Any help much appreciated.

[attainteddragon]

Re: LG 60PZ570 main board failure?

if you are getting good clean test patterns, then it is a main problem.

you can try to do a reflow of the main chip as they are renown to suffer from bga failure, otherwise, a replacement will make it all shiny again.

[LGLover]

Re: LG 60PZ570 main board failure?

Yes nice clean patterns. Tried a reflow, no luck there but I'll try again. A little longer/hotter this time.

[tw2005]

Re: LG 60PZ570 main board failure?

Definitely mainboard

[LGLover]

Re: LG 60PZ570 main board failure?

So I've replaced the mainboard aaaaaaand... no change.

Same test pattern result. Thoughts?

[dick_barton]

Re: LG 60PZ570 main board failure?

I would be suspicious of the replacement board since the test pattern is correct.

[tw2005]

Re: LG 60PZ570 main board failure?

Yeah. Where did you find a board? has to be bad mainboard trust yhe lvds cables are connected

[LGLover]

Re: LG 60PZ570 main board failure?

I've just tried a second brand new board direct from LG. Same result.

I've also double checked both ends of all cables leading in/out of this board.

Bizarre huh?

[rocketdog]

Re: LG 60PZ570 main board failure?

For the buzzing it might not make a difference but make sure all the screws are tight especially on the earth tags. I've had similar issues in the past not as loud but not far off as for the main issue I would agree that it looks like a main pcb issue did you change the main board(with hdmiports ect on it) or pcb shown in the vid as the test patterns could be generated in either thus causing a misdiagnosis. Or I could be completely wrong but worth a punt XD

[LGLover]

Re: LG 60PZ570 main board failure?

I think I may have gotten my terminology mixed up. I've replaced the board with the main chip on it.

This is kind of embarrassing but have you all been referring to the board with the I/O ports?

[LGLover]

Re: LG 60PZ570 main board failure?

Yep. I'm an idiot.

Chucked the 'main board' into the oven for 20 mins. TV now starts/runs just fine.

Fortunate as this board is NLA from LG.

[attainteddragon]

Re: LG 60PZ570 main board failure?

as long as it is up and running again, that is all that matters.

hope it holds out for a while. enjoy.

[augiedoggy]

Re: LG 60PZ570 main board failure?

Yep. I'm an idiot.

Chucked the 'main board' into the oven for 20 mins. TV now starts/runs just fine.

Fortunate as this board is NLA from LG.

it wont last long trust me I had the same set and same issue.. you can get new boards for $100 here in the states and refurbed ones for $75.. all over ebay. its THE most common fault with this model..

Still better than some of the new led lgs which are trash IMO.. Ive replaced so many bad leds on them its not even funny. Lg actually overdrives the leds so they fail right after the warranty is up in many cases..

[freakaftr8]

Re: LG 60PZ570 main board failure?

it wont last long trust me I had the same set and same issue.. you can get new boards for $100 here in the states and refurbed ones for $75.. all over ebay. its THE most common fault with this model..

Still better than some of the new led lgs which are trash IMO.. Ive replaced so many bad leds on them its not even funny. Lg actually overdrives the leds so they fail right after the warranty is up in many cases..

I have worked on more LGs with failed backlights than any other brand so I must agree in that statement.

And every single one of them that I've worked on the backlights were cranked up to 100%

After a repair I always turn them down to at least 60% and tell the customer to leave them there

[augiedoggy]

Re: LG 60PZ570 main board failure?

I have worked on more LGs with failed backlights than any other brand so I must agree in that statement.

And every single one of them that I've worked on the backlights were cranked up to 100%

After a repair I always turn them down to at least 60% and tell the customer to leave them there

I generally do to but the problem is if they select a different picture preset that all goes out the window. I see at least one person here is adding resisters to bring the voltage down.

[freakaftr8]

Re: LG 60PZ570 main board failure?

Thats a great idea!