[1000mp] Cooling fan causes buzz in transmit audio on Mark V

[1000mp@mailman.qth.net]

No, it is due to a poor transformer design in the 91B. It is mentioned in the 
"trouble shooting" section of the 91B manual. VERY careful placement of the 
mic can help null out the coupling. Many folks have had the problem. In some 
cases, changing out the transformer in the supply will reduce the problem.  
It may have been worse in a particular run of amps. Three of my friends all 
bought over a 3-4 month time and all have the same problem, even with the mic 
30-40 inches away from the linear. And, all of us are RF engineers able to 
verify the problem. Hi. I think it was found only in the 91B design.

GL
Bruce, AA4Z