Power Supply Driver D2011K

[jaipursky]

Hello Folks,

I need little help while I am trying to repair Samsung UN55HU7200FXZA UHD TV.
Symptom: No Power, no standby indicator, no other lights of course.
Power Supply: BN44-00781A
On the Power Connector, I think stand by voltage 5V should always be present. There is no 5V present. Other supply of 13V will not work when processor initiates it.

MOSFET Driver for 5V DC is D2011K. Its datasheet is attached. thinking it could be bad. I get voltages up to this MOSFET chip. but not sure if its getting feedback or not, its OPTO reads 0.9V on low side.
This MOSFET Driver is getting 165 V DC from the Bridge Rectifier on HOT Side.

I supplied external 5V and Stand by Indicator is works, but Remote and PWR SW still doesn't respond. TV doesn't power on as expected.

Spare Power supply board is expensive and I don't want to order it without knowing if the Processing motherboard is good or not. one I find the cause I will get a new supply.
No visible signs of burns or faulty components on either boards.
High res photos attached. Also attaching similar PWR Supply schematic which shows use of D2011K (for reference)

Please advise how would you isolate the issue.
Thanks!