Whelen A490A -strobe flashing continuosly

My right Strobe light when "on" flashes continuosly. I have swapped the left wing power supply to the right and the Strobe operates normal. Has anybody experienced this behavior? Any thoughts? Whelen's technical response is to replace the PS. My thought is that a component has failed but which one is the question. I can't find a circuit diagram for the PS.

PS trouble

Whelen will not give you a schematic... they consider the PS non repairable. I left a phone message for you about a replacement unit... 1/3 of new.