Panasonic Plasma TC-P42UT50 flickering during warm up (also shutdown 7 blinks)

[lfcastilhos]

Hello,

When I power on the TV, after almost 1 minute (between 50 to 80 seconds) the image flickering and disappear for a while (1 to 2 seconds), sometimes the TV shutdown and front LED blink 7 times.

When the TV recover from flickering it works perfect for hours.
The issue happens when the TV is off for more than 5 minutes, it means when the TV is cold and caps are discharged.

I bought SS and YSUS boards from a guy who broken the TV, 2012 Plasma troubleshoot guide says 7 blinks could be and issue with SU/SD, SC and SS boards, I replaced both with no lucky.
SU,SD and SC are integrated into a single YSUS board, both YSUS and SS green LEDs flickering when the issue happens, looks like power outage or surge.

I'm wondering it's an issue with Panel or Logic A Board.
For me it looks like a bad cap that discharge when it's warming up.
I'm ordering a power supply to test.

Need help to troubleshoot!

[ReeceyBurger123]

Re: Panasonic Plasma TC-P42UT50 flickering during warm up (also shutdown 7 blinks)

Why you replacing stuff with no diagnoses ? This set suffers with bga issues on the A board which also drives the panel.

[lfcastilhos]

Re: Panasonic Plasma TC-P42UT50 flickering during warm up (also shutdown 7 blinks)

I've tried some initial troubleshooting with no luck.
So I found used SS and YSUS with a good price and I decide to try replacing those parts cause those are the most probably cause for 7 blinks.

I beleive it is probably a energy surge or discharge coming from one of those boards or power supply.

How can I troubleshoot BGA issue on A board? And why it happens every time at the same time? Not intermittent.

[lfcastilhos]

Re: Panasonic Plasma TC-P42UT50 flickering during warm up (also shutdown 7 blinks)

ReeceyBurger,

I've worked again and all boards looks fine, VSUS, 15V, 5V, Vad, all looks fine (except main board).
I think you were right, I don't have right tools to troubleshoot BGA so I tried to keep one chip cold using a ice cube water inside a plastic bag (I know that looks weird).

I kept the ice on one chip during 3 minutes and TV works , when I remove the ice, after 1 minute the issue happens again.
I tried again and kept the ice during 5 minutes, again the TV works fine when the chip is cold, when I remove the ice, again after 1 minute the issue happens.

So, looks like the problem is the BGA on main board, my nightmare now is how can I fix that, the board is almost impossible to find in my country ( I can't import cause digital TV tuner is not the same), in house reflow looks like a bad solution, reballing is expensive and no guarantee it fix the issue.

What would you do?

[ReeceyBurger123]

Re: Panasonic Plasma TC-P42UT50 flickering during warm up (also shutdown 7 blinks)

Ahh its the screen controller Ic, grrrr panasonic really piss me off why they didn't heatsink it I will never know Also either change the Mb and on a replacement add a heatsink to that chip or give it a reflow and then add a heatsink after wards.

[vinceroger69]

Re: Panasonic Plasma TC-P42UT50 flickering during warm up (also shutdown 7 blinks)

a reball is the best answer but a lot of people have had lasting repairs with a diy refow using flux. Im typing on a laptop i reflowed about 3 years ago and is still working fine, i guess its how the reflow done ive known people to verheat ics and make them worse even if you get a replacement mainboard in a short time you may have the same issue, if this was my tv i would do a reflow and add a fan.have you a shop etc you can use and get a proper reflow done using a bottom heater etc.

[lfcastilhos]

Re: Panasonic Plasma TC-P42UT50 flickering during warm up (also shutdown 7 blinks)

Thank you guys, I think I'll look for a reball or reflow service while I look for a new board.
I'm afraid to reflow using a heat gun air and bottom heater is also a problem cause there are some very tiny components under the chip (board).
I'll also buy a decent heatsink