[Amps] AL-1200 Pop

[Dana Roode]

I just finished replacing the open frame relay in my old AL-1200 with the 
Ameritron relay PCB mod.  Put it all back together, seemed to work fine, 
tuning on 40m.  Moved to 160m, had the Amp in Standby while I set the output 
power on the exciter.  Heard a loud Pop - exciter power only.

I turned the Amp off for awhile, then tried it again.  It still works fine. 
   I opened it up looking for a visibly bad component, none found.

Any ideas what this might have caused a Pop in Standby?  Should I worry?

   Dana