Panasonic TH-P50U30A Board Change and chip got burnt :(

[kaacu]

Hi all,

Let me start by describing what has happened from the beginning.

When I was watching TV, the TV suddenly went black with a pop sound. Green light was on but remote was not working. I turned off and on the power it just showed the green led but the screen is still black without backlight. After diagnosis with resistance test I reckon the problem of SC board (the green light on board was also gone). So I sent the board to a engineer to fix.

Got it back today and put it back to TV and expected everything is alright. The green light of SC board is back as soon as the power is on, however, a chip (C653) on SU board started burnning and eventually detached from the board. At the moment I dare not turn it on again. Apparent SU board is not working anymore...

Anyone has idea know what's going on? Would it be a double fault at the beginning on both SC and SU board? Any further test I can do in order to fix it?

Thanks a lot.

[bob_m_54]

OK, this is why you need to send the whole TV to a TV repair man, not just one board that you suspect. Without any knowledge of your particular TV, it could be a number of reasons, but one thing that will often affect multiple parts of the TV circuit, is a power supply problem. Often times, electrolytic capacitors in the power supply will dry out and get a high ESR, causing problems like power supply voltages too high. This used to be a very common fault in pre-flatscreen TVs, when I was in the business, and was probably 75% or more of the root cause of most faults.

[tw2005]

Hi all,

Let me start by describing what has happened from the beginning.

When I was watching TV, the TV suddenly went black with a pop sound. Green light was on but remote was not working. I turned off and on the power it just showed the green led but the screen is still black without backlight. After diagnosis with resistance test I reckon the problem of SC board (the green light on board was also gone). So I sent the board to a engineer to fix.

Got it back today and put it back to TV and expected everything is alright. The green light of SC board is back as soon as the power is on, however, a chip (C653) on SU board started burnning and eventually detached from the board. At the moment I dare not turn it on again. Apparent SU board is not working anymore...

Anyone has idea know what's going on? Would it be a double fault at the beginning on both SC and SU board? Any further test I can do in order to fix it?

Thanks a lot.

Not a common fault I've read about but possible. Question is did it display an image? If the Su was blown like the output buffers you'd have a 7 blink shutdown and a bad buffer can blow the SC.

I would get a meter and set to diode, check between all the output pins and Vfg for short. Depending on the polarity of the leads it'll be OL or 0.7. Anything dead short , that chip will be toast.

If it's not shorted, I'd say the cap failed. 0.1uf 250V and you may as well replace the others.

Common failure is normally the SC or the SU blows a couple of chips. If you're chasing a board any Su from a 50" U30,ST30,Gt30 and VT30 will do. The 3d models have heatsinks otherwise it's the same board.