Panasonic Plasma TX-P50STW50 - 7 blink error code - Z-sustain board TNPA5524 defekt

It was about time to fix a Panasonic Plasma TV, my favorites! I recommended this one to a friend, who was looking for a 50 inch. It was listed on eBay. The seller had observed the 7 blink code. My friend got it for 200€.

A look inside:

Panasonic finally picked up the idea to install a woofer speaker with its own cabinet. The TV also sports WiFi and Bluetooth for the 3D glasses. My GT30 has none of that. 

The first check in a 7 blink Pana goes to the SC board (Y-sustain). It had no short on the supply line and none of the semiconductors measured suspicious. According to the service manual, on this model, the 7 blink can also be caused  by the SS board (Z-sustain). And lo and behold, this one had a short on the supply line.

A closer look revealed shorts on the following semiconductors:

As the IGBT transistors are working in parallel, I unsoldered them and measured them individually. As it turned out, only three of the 30F132 IGBT transistors were dead. Both from the center and the one in the middle of the group of three.

Anyways, a new board was necessary. The plasma TVs of the previous generation used the 30F131, which has a lower current pulse capability. I could not cannibalize my spare SS board.

My favorite supplier flattvparts.co.uk had one board left. Now, you need to be very careful here, because there are many versions of the TNPA5524 board around, which all look similar, but they aren't equal. 

Check this label:

There are RFUU, REUU, RHUU (and probably more) types around. Each has a different configuration of transistors and coolers.

The new board fixed the TV. I found brownish areas on the old board, a sign of high temperatures. To improve cooling, I unsoldered all coolers from the old board and put them in the areas where the most heat seemed to build up. I also measured the temperatures. I put a bigger cooler on the transistors, where one maybe had been the reason for the failure.

On the SC board, I put the same cooler on four transistors, which seemed to heat up more than average.

Evangeline Lilly was beaming into the room. An image only the best plasma TVs are capable of. Just compare it to the Philips LCD I fixed recently: Lilly on LCD. The difference in color spectrum is striking.

This is a brilliant TV. The picture is awesome and finally, also the sound has become acceptable. The ST series misses more fine-grained image adjustments, but the available modes work very well right out of the box.

Here is the list of the high power semiconductors:

SC only

D RFUH25 (SC)

D DAF30A (SC)

T DG301 (SC)

T 30F131 (SC) can be substituted with F132

T R5007 (SC)

T RJP6304 (SC)

SS only

T DG302 (SS)

T RCJ200 (SS)

T RCJ220 (SS)

SC & SS

D RFUH20 (SC, SS)

T 30F132 (SC, SS)

T 45F132 (SC, SS)