Sony - KDL-32EX400 trouble shooting no turn on

[Doc38343]

I am trying to figure this out. My brother in law said he thinks it was a power surge from a storm that got it.
I have been trying to test the boards but when i looked this one up in Google I found a place that said it was the main board.
Here is my dilemma... I think it is the power supply because the ONLY voltage coming over to the main board is 3.3v and that is on 2 leads only ALL the rest are 0000v.... (photos attached)
Now I could assume the main board sends voltage signal back to the power supply to trip mosfet and relays..
But I just think it is a bad power supply because the 12v raid is not live on the cable as well as it seems odd for it to function in the way described.

So time to ask the experts... trying to learn more so Thanks in advance.

Doc

[poot36]

Most TVs have a low voltage standby line from the power supply to monitor the remote control and the power button.  When the TV detects that you have turned it on it will send that low voltage back to another pin on the power supply instructing it to turn on the rest of the outputs.  Check that the power switch is getting power and if it is not then the main board does have a fault on it.  Try to find the service manual for the TV as it sometimes will have various tests that you can preform to check that the main board is the problem.

[silviustro]

As poot36 said, most TVs have a 3.3V standby power line going to the main board. Once it receives the command to turn ON, it signals the power supply to switch the 12V and 5V lines ON as well. There might be something wrong with the main board not signaling the power supply to switch the voltage lines ON.

I know this is basic stuff, but if it was a power surge, check the fuses.... always check the fuses.

[mzacharias]

You should have a turn-on (Power-On?) line from the main board back to the power supply. Monitor this line while the power button is pressed. Should change states, High to Low or vice-versa.

First of course, check fuses and any other fusible devices on the power supply board.

A shortcut might be to see if there is any DC voltage on any pins of the remote sensor. If not - high likelihood of the main board being bad.