Panasonic TC P54VT25 Loud POP

[Steve T]

Hello

I am new to the forum searching for some help. I have bee ncouring the Internet with very little success.

The other day I turned on the power to my surge supressor, the power up the Panasonic Viera plasma. There was a very loud pop from the rear and the smell of burnt electronics. I also have the 10 LED blinks.

Following the troubleshooting instructions from these forms, I tried unplugging the SC and then the SS boards. There is no sound at either step and the LED always flashes 10 times.

This leads me to think that it is the power supply board (ETX2MM807MVH F2). There are absolutely no signs of burning or discolouration on the board and all of the fuses check. The capacitors do not show any signs of buldging or leakage, and all of the Zener diodes appear intact. Also there is no further smell of residual burning.

If anyone has any ideas of where to look for damage, the help would be very much appreciated. What bothers me the most about this "blowout" is that the tv has less that 50 hours run time in nearly 3 years.

Thanks for your replies.

Steve

[tom66]

Re: Panasonic TC P54VT25 Loud POP

First item may help:
http://www.toms-service-manuals.com/...&typekey=0&p=1

SM:


10 blinks is probably SC or SS shorted to 15V causing over volt.

[Steve T]

Re: Panasonic TC P54VT25 Loud POP

Thanks for the reply Tom66. I just want over those boards with a magnifying glass and there are no obvious signs of burns or bulges. My electronic knowledge is pretty basic, what should I look for?

I have the manual downloaded from elektrotanya. The first link did not have my model number.

Thanks Steve

[selldoor]

Re: Panasonic TC P54VT25 Loud POP

Suggests you post good clear pictures of the set with the back off and front and back of each board. Bangs and smell do not usually leave no clue. Have you found any fuses?

[tw2005]

Re: Panasonic TC P54VT25 Loud POP

Thanks for the reply Tom66. I just want over those boards with a magnifying glass and there are no obvious signs of burns or bulges. My electronic knowledge is pretty basic, what should I look for?

I have the manual downloaded from elektrotanya. The first link did not have my model number.

Thanks Steve

When you disconnected the SC board and still got SOS10, was the ribbon at SC20 removed ?

If you have a multimeter and assuming it's a SC board failure here's some suggestions.

Check:

Short cct across the SC2 pins

Shorted out transistors

eg. Q16661(Q661) a common one, most of the heatsinked ones can go short.

FET driver IC521, I've seen the odd photo of that one burnt. The 15V feeds that IC, resistance across Diode D790 on the SC just around the Sc20 area should be about 1.4-1.5 Kohms. If it's low a good indication IC521 is bad.

SMD resistors around that can burn, so too gate resistors on the transistors,

I've had a tiny 3.9K smd resistor make a loud pop and smoke , very hard to see, a jewellers magnifier helps with the really small stuff. Realistically, you only need to find 1 shorted transistor or Sc2 to deem the SC bad and quicker than spotting potentially a pinhole in some smd component.

The G20/G25 guide may also help a little although the 3D models are different but the SC is similar.

[Steve T]

Re: Panasonic TC P54VT25 Loud POP

Thanks to all that replied. It was the SC board. Panasonic replaced the board for free. I did have to pay for a diagnostic and house call. Hope this thread helps some one else with the same problem.

Steve