HELP: KWM-2 Motoroboating on Rx Audio
Norm VE3CZI wrote:
Gain Control is increased the RX audio
starts to Motoroboat , which overrides the incoming audio.
The motoroboating occurs even when the RF gain is turned down and the audio
control is increased.
I suspect this is NOT normal, but have never had a KWM-2 previously.
It is very much not normal. You have a filter cap somewhere in the audio
section, most likely somewhere in the power amplifier section. While you
are in there, I believe there are some cathode bypass caps that ought to
be changed out too.
Can anyone advise if this is "normal"? OR if "not"...has anyone had this
experience and can offer any advise as to
a possiable solution.
Motorboating is a low-frequency oscillation usually caused by the power
supply not being stiff enough; a high level signal pulls the B+ down,
which reduces the gain which reduces the load so the B+ goes back up
again... and on and on.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
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