Sony KDL-55EX620 Won’t Turn On 2 Blinks

This TV was flashing a 2 blink code which is a power supply error.

A service and training manual can be found here.

Power supply board part number is APS-299 (1-474-303-11 147430311).  Searching on ebay found repair services and repair kits for this board.

Posts on badcaps indicated potential shorted transistors Q6101, Q6102 and open resistor R6540.  When i tested these parts, all three had failed.

Q6101 and Q6102 are shown in the schematic as TK5A50D.  These are 500V, 5A N-Channel MOSFETS.  I had FDPF7N50U (Digikey #FDPF7N50U-G-ND) spares from a previous repair.  R6540 is listed as a 0.1 ohm 1/2W resistor and I temporarily substituted the part with a 0.47 ohm 1/2W fusible resistor I also had.  Digikey substitute would be 0.1DMCT-ND (0.1 ohm, 2W fusible).

With these 3 components replaced, the TV powered up.  This failure is similar to a previous repair on a Sony KDL-46EX400  here.

This video describes repair of a 2 blink code on a KDL-46EX523.  The boards are very similar but the designators and transistors are different.

 

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