Jorge,
Since you have made adjustments to PA circuitry, I am guessing that you
hear this hum on your sidetone during transmit? Maybe it is a power
supply problem. Perhaps the filter capacitors are going bad or the diode
bridge has a failed diode. What happens when you transmit at very low
power? Is the amplitude of the hum dependant on the amount of current
being drawn from the power supply? Can you try a different power supply?
How about paralleling a big fat umpteen thousand microfarad capacitor
across the DC power supply line? Does this change anything?
DE N6KB
My Omni VI pls has recently developed an intermittent
hum which can be heard through headphones while on CW
mode. I did the current limiting and power amplifier
bias adjustments, hoping that either would solve the
problem but no luck.
Looks like the problem has to do with the DC input
board, Has anyone has a similar problem.
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