it is not the issue with PSU because power lost error message is coming only with One board I even disconnect other boards and connect only this board and error still appears, once I disconnect this specific board and reconnect the remaining two device is hashing normally
so I think this board is already dead and shorted somewhere ,
Did you buy a used(2nd hand) miner?
If not, and then you bought them directly from Bitmain you send the hashboard for repair.
Can you try to check the hashboard physically and maybe there are some burnt parts under the power terminal. If not, try to clean the whole power terminal and some parts with lacquer flo thinner then try to run it again.