[AMRadio] Muting the R390 on transmit

Larry Szendrei ne1s at securespeed.us
Wed Dec 2 14:43:22 EST 2009

> Thanks for the reply, Grant. My R 390 doesn't mute when terminal 9 is
> grounded. I have connected an alligator clip lead to terminal 9 and then
> connected the other end of the clip lead to terminal 16 which is ground
> and there is no effect. I can't figure out why there is no effect when
> terminal 9 is grounded. What do you think, Grant? I do not have a manual
> or schematic for the R390. 73, John, K5PGW

You didn't mention whether the Break In switch was "on", which, as Grant
said, must be for it (=grounding the break-in terminal) to mute the
receiver. Or, maybe there is a problem in that circuit in your R390. I
used this function on my R390/URR, and it worked exactly as Grant


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