Samsung LN32A450 No Power

Other model numbers: LN32A450C1D and LN32A450C1DXZC

This TV uses a BN44-00214A (Dongyang MK32P5B) power supply board.  Schematic available here.  Opening the back of the TV, I found one bulged capacitor CM858  which I replaced.  The TV still had no power so when I checked the main fuse,  it was blown.  I replaced it with an 8A I had available.  I plugged the TV in a second time but this time I created some sparks.  A jumper by the big filter cap had blown apart along with the leg of one capacitor beside it.  The main filter cap had also bulged.  Researching the board number on badcaps found this board has an issue with the glue used to cover pins .  The glue drys out over time and becomes conductive.  It is used to prevent dust accumulating at the legs of high voltage components which may ignite.   I scraped off all the glue on the board, repaired the jumper, replaced the filter cap with a used one from another board, and resoldered the damaged capacitor (tested good on my meter).  I found a 6.2A fuse from another board and plugged it in again.  The fuse blew again but no sparks.

I checked the bridge rectifier with my multimeter and found a short between the + and – output pins.  This was traced to a short on QP801S (600V/10A/N Ch FET).  I temporarily replaced it with a similar FET and the TV finally powered up.  The inrush current limiting resistor NT811S (5 ohm) was also cracked so I replaced it along with all the large electrolytic Samwa capacitors.

Here are the part numbers for Digikey

QP801S – FCPF11N60F-ND 600V 10A N-Channel FET
FP801S  – 507-1215-ND 6.2A/250VAC ceramic fuse
NT811S – 495-4466-ND – ICL resistor 5 ohm 6A

Electrolytic Capacitors

CM851, CM852, CM868 – 680uF/35V
CM856 – 470uF/25V
CM858 – 680uF/25V
CM861 – 3300uF/10V
CB852 – 2200uF/10V

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