PN58A550 Main Board 3.3V Power Suppy Repair
Repair of Main Board 3.3V power supply on a 2008 Samsung PN58A550 Plasma TV.
Use this procedure at your own risk! Make sure power is unplugged when removing and connecting boards.
Time Index 00:00 Demo of Problem and bad 3.3V waveforms
Time Index 05:45 Board repair. Replace 2 parts
Time Index 17:06 Demo of repaired TV
My Samsung PN58A550S1FXZA Plasma TV started acting up a few weeks ago. The screen would scramble when I first turned it on (cold start), but then it would power-cycle self-reboot and the picture would be OK after that (after a warmup?).
I isolated the problem to a bad tantalum cap C102(10uf,10v) and/or the 5V to 3.3V buck regulator IC101 (MP2363DN) on the Main board. These parts are on the back of the Main PCB. If I applied a little heat to those 2 parts before I powered the unit on, it starts up fine.
If you are not sure this is your problem, check out my other video, which shows how to generate some test patterns with the Main board disconnected. • PN58A550 Plasma TV 'Logic Main Board' Test
Parts from Mouser:
MP2363DN-LF $3.34 https://www.mouser.com/ProductDetail/...
10uF 10V $1.54 https://www.mouser.com/ProductDetail/...
Shop Jimmy has a repair kit that contains these 2 parts:
https://www.shopjimmy.com/samsung-bn9...
The ShopJimmy kit has one part you may not need (the audio chip), and the cap in their photo appears to be a ceramic cap instead of a Tantalum. That may be important.
Good Luck!
PN58A550S1FXZA
PN58A550
PN50A550
Logic Main Board
LJ41-04802A
PCB LJ92-01457A
PBA BN96-05645A
Main Board
Model Pearl
BN41-00975C(2008.07.31)
BN97-02039B
BN94-01660B
SMPS PSPF701801A BN44-00183A (Switched Mode Power Supply)
Here is a link to the schematic of the SMPS board.
https://elektrotanya.com/samsung_bn44...
I took the pdf to FedEx Kinko's and printed the file on 11x17 paper and it was very readable.