Whelen Responder II Model VPPS6C

[wsmm]

Bought used, checked it out yesterday and it worked fine. Alternated between left and right strobe. Went to show it to my wife today and only one strobe light would work. Loosened the power supply and tried all three connectors on the one side and they wouldn't light the strobe. Wired the strobe into one of the connectors on the other side and both strobes flash now at the same time. Is there a fix I can do, or is one side of the strobe power supply shot. If the power supply is bad is there somewhere to get a new or used one cheap?
Thanks,
Bill