Variac shows regular pulses of over current on power up through current limiter lamps.
Looking for short ....power board vs main board. Protection circuit must be activating...
curious, no power on standby pin, (others good) but tv has red light..isn’t stand by voltage always present and needed for status light?
disconnect main board....no short activity ....disconnect disconnect t- con board..still short pattern
led strips just repaired no shorts there....all working
caps, mosfets check out on power board less I’m missing something obvious...don’t know where to go here!

 

disconnect main board....no short activity ....

This would seem to indicate the problem is on the main board.

 

+1 Main board faulty...

 

Thank you for your help. I am puzzled by a zero voltage on power supply board stby pin....is this not always present?

 

It may be that the main board fault - perhaps overcurrent - has been detected by the power board and it has shut down. This is usually reset by a power cycle.

 

It may be that the main board fault - perhaps overcurrent - has been detected by the power board and it has shut down. This is usually reset by a power cycle.

Another question..... I am still perplexed why there is no standby voltage when the TV is on at the S TB Y pin. And in looking at that circuit I removed an optocoupler that showed voltage each way across the cathode/ anode in circuit....but when removed tested good? Does this indicate a short?

 

I removed an optocoupler that showed voltage each way across the cathode/ anode in circuit

"showed voltage"?
Do you mean on the diode test range?
If so then you need to consider the components in the curcuit around the coupler.