[Amps] Need Diagnostic help

[Will Matney]

Tom,
Does the amp do this while at idle or only when it's keyed up? If it is 
when it's keyed, I'd take a look at my antenna and or the line. I have 
seen them arc inside the coax connector making a high pitch whine. I 
have also seen this at the load capacitor between the plates. This being 
due to a bad coax jumper going to the watt meter. If it's doing it at 
idle, it could be possible that it's self oscillating or has VHF 
parasitics. If so, the band switch or other components could be arcing. 
One last thought is to check all solder joints, especially ones on 
printed circuit boards.

Will Matney