Repairing Samsung plasma TV PN64D550

[pap]

Hi all!
First post and fairly new at fixing electronics, so all pointers will be appreciated!

I recently picked up a huge Samsung plasma TV (Model PN64D550) for free as, according to the previous owner, it was no longer working. I am trying to repair it but the information I found so far hasn't been able to help me narrow down the failure point on this specific unit.

• very useful to diagnose power supply issues around the FETs, but it doesn't seem to be the issue for my unit
• very similar issue. same power supply board model number (#BN44-00445A)

Here's what I'm experiencing with this TV: When the TV is plugged in, there are 2 clicks (relays) from the power supply board, and the standby light blinks 6 times, then turns off. I can then press the power button, and the standby light momentarily blinks once, but nothing happens. Same behavior when I press a button on the remote: the standby LED blinks a few times, but the TV does not do anything else. I also connected the LAN port of the back of the TV to an ethernet hub, and the LED on the hub is solid green, indicating that the main board in the TV is likely working. I also noticed that after 5 minutes, the unit apparently reboots: the standby LED blinks another 6 times, and the cycle seems to repeat over and over. Otherwise, the TV is not displaying any activity: no sound, no flashes on the screen, nothing else.

I took down the back cover and started looking for issues. All caps seem to be in good condition. The label in the back of the TV indicates that Vs should be 217V and Va to be 91V. I suspect however that this voltage is only provided to the sub-boards when power is actually turned on, so at the moment, the TP Vs and Va don't show anything. On the power supply board, the label for the connector to the T-CON board indicates that 5.3v should be present on pins 5 and 6 of the connector. My multimeter agrees with this. Voltage on the main board connector also appears correct (15V and 6.2V). The 3rd connector on the power supply board feeds the Y and X assemblies, and again, this does not show any voltage at all at this point.

I also see a green flashing LED on the T CON board (slow blinking, approx every 2 seconds). This seems to confirm that the voltage provided to that board is fine also.

I visually inspected the other boards, and could not notice anything unusual (no burnt components, flaky joints, etc).
I unplugged the Y MODULE power supply cable, and the issue remains the same (standby led blinking, but won't power on).

My questions:

• Should I be able to read a value for Vs and Va even if the unit is on standby?
• Would it make sense to try to bypass standby mode using a small resistor like here https://youtu.be/dswtNRiZwN8?t=798 to determine if Vs is within specs?
• What else can I try to further diagnose this?

Thanks for your help and input!