Hitachi 42PD5200 PSU query?

[quaduplex]

Hi all,

My first post on this forum. It seems a very active and helpful place to be. I'm a bit of a newbie to the TV side of electronics but learning fast.

I have a Hitachi 42PD5200 that was exhibiting all the signs of the infamous 10 ohm resistor failure. Pulled the PSU, both 10ohm resistors were o/c. Q201 was also shorted. Q220 seemed ok. Replace transistors and both resistors.

Checked IC201 as per the KIT54 guidance as it seemed fine with no apparent shorts. Daughter board was removed from board and checked - transistors were still in circuit however but no shorts apparent.

Assembled it all back together and power on. Within 2 seconds of switch on and with a relay click, Q201 blows in a big way

I am wondering if I've missed something on the Q201 daughter board or as per the faults list on here -

"42PD5200/5300-dead -check and repaced R005(10oM),R003(10oM),C111(10n) beside T101 5v PS and Optocouple PC101,PC001 and check Transistor for short circuit -Q201(2sk2843)"

if the photocouplers could cause this? How are photocouplers checked?

Any help or guidance is much appreciated.