LG 60PX950-AA sound, no picture - panel seems to "power up"

[TehEkHo]

Hi all - looking for some help resolving an issue with my parents' LG Plasma - it's a 2010 manufactured LG 60PX950-AA

Initially we lost HDMI inputs, which wasn't an issue as they never needed them, however, more recently it started to fail with sound but no picture, first, after around 30-60 minutes of viewing, but now the panel doesn't power up at all. Dad ordered and replaced a YSUS board, however, I have since come to understand that the old and new boards may not be compatible. I'm now looking for assistance in identifying and replacing the component responsible for the lack of video. I suspect it's related to power to the panel. I'm comfortable working with electronics, but my knowledge of TVs is limited to turning them on and changing channel

Board IDs are as follows:
PSU: EAX61432501/9
CTRL: EBR70137601
ZSUS: EBR63450501
YSUS: EBR70503101

Panel is a PDP60R1033

I have placed the original YSUS back in place

Va measures 60V on the test point on the PSU, which is in spec with the panel.
Vs measures 203V on the test point on the PSU, which is in spec with the panel.

While testing, I noted that the panel seems to be “powered up” - i.e., there's a glow on the panel which disappears as you turn it off.

Any guidance would be appreciated

[ReeceyBurger123]

Re: LG 60PX950-AA sound, no picture - panel seems to "power up"

You could of done some research on how to run the test patterns, quite obvious that this is a main board fault as the hdmis dropped out. Run the test patterns on the control board with the Lvds cable disconnected and let us know if you get the test patterns. If so replace the mainboard.

[TehEkHo]

Re: LG 60PX950-AA sound, no picture - panel seems to "power up"

You could of done some research on how to run the test patterns, quite obvious that this is a main board fault as the hdmis dropped out. Run the test patterns on the control board with the Lvds cable disconnected and let us know if you get the test patterns. If so replace the mainboard.

Good call - I couldn't access the information on running test patterns earlier - tried again now and got the picture showing the points to short.

Have test patterns. Going to leave the set running for a while with them, but, looking at a main board replacement by the looks of things. May give the oven re-flow a trick if that's the case as it can't make matters any worse

[mmartell]

Re: LG 60PX950-AA sound, no picture - panel seems to "power up"

You could of done some research on how to run the test patterns, quite obvious that this is a main board fault as the hdmis dropped out. Run the test patterns on the control board with the Lvds cable disconnected and let us know if you get the test patterns. If so replace the mainboard.

+1 nailed it.

[TehEkHo]

Re: LG 60PX950-AA sound, no picture - panel seems to "power up"

OK, more info - on the test patterns, the TV switched itself off after a while - say 15 minutes - as in entered standby. I don't think that's normal, can anyone confirm?

[TehEkHo]

Re: LG 60PX950-AA sound, no picture - panel seems to "power up"

So - managed to test that the main board was at fault by borrowing the one from my TV, now that it's out of storage (Long story). Correct diagnosis on the main board.

Tried an oven re-flow - 8 minutes at 195C, and all is back to normal, which is nice as I couldn't find one available when searching.

[ReeceyBurger123]

Re: LG 60PX950-AA sound, no picture - panel seems to "power up"

Hmm maybe send it back ? Also I very very strongly suggest you remove the thermal pad off the cpu heatsink and replace it with thermal plaster and add a fan to the cpu if not same fault will happen shortly.

[TehEkHo]

Re: LG 60PX950-AA sound, no picture - panel seems to "power up"

Hmm maybe send it back ? Also I very very strongly suggest you remove the thermal pad off the cpu heatsink and replace it with thermal plaster and add a fan to the cpu if not same fault will happen shortly.

Yeah, good call on the paste at a minimum. My brother does have some thermal paste floating about, but I couldn't find it when I was putting things back together. I'll suggest the replacement of the thermal pad with paste when I speak to dad next, as well as said fan

Heatsink was a pain the the butt to remove - the barbs that hold it in were troublesome!

[ReeceyBurger123]

Re: LG 60PX950-AA sound, no picture - panel seems to "power up"

Ahh dam, also you will need thermal plaster not paste to glue the heatsink to the cpu Try and keep these Plasmas alive.

[TehEkHo]

Re: LG 60PX950-AA sound, no picture - panel seems to "power up"

Ahh dam, also you will need thermal plaster not paste to glue the heatsink to the cpu Try and keep these Plasmas alive.

I managed to save the barbs - you think it's worth ditching the barbs and gluing it on regardless?

[Mad Capper]

Re: LG 60PX950-AA sound, no picture - panel seems to "power up"

Tried an oven re-flow - 8 minutes at 195C, and all is back to normal

Did you use any flux on the main BGA IC under the heat sink when you re-flowed it? Anyone know if you explicitly should or should not use flux? If using flux do you need to clean it out after? How on a BGA, just flush it with isopropyl alcohol?

Did you remove the heatsink for the re-flow or leave it on? Any guidance on this?

Did you use a re-flow oven or just a regular home oven? How did you choose the duration and temperature?

ReeceyBurger123:
Would you get the power for the additional fan from somewhere in the set or use and external power supply? For additional cooling within the set do you have an idea how many fans you could run by taking power from the set without it causing a problem?

Thank You

[dick_barton]

Re: LG 60PX950-AA sound, no picture - panel seems to "power up"

A lot of fans are low voltage, low current. If you have a 5V or 12V supply on the set then find a fan at that voltage. Currents tend to be less than 200mA. I have one next to me 12V, 130mA.

[Mad Capper]

Re: LG 60PX950-AA sound, no picture - panel seems to "power up"

Thanks. Good to know for future use.

Do you think adding cooling fans to plasmas with only passive cooling is beneficial? Such that the fans are exhausting out the top vents above the YSUS and ZSUS should one be able to get a fan in there.

[Nick's Tvs]

Re: LG 60PX950-AA sound, no picture - panel seems to "power up"

Mad Capper, if your board fails again, let me know as we can perform a re-ball on it for you. The oven trick usually only works temporarily and is not a permanent solution even if the chip is soaked in flux. And yes a fan will help a lot as this is an issue with cracked solder joints under the main BGA chip caused by overheating.