One of the more annoying feats of mis-engineering/programming in the MP is
the stupid BEEP function implementation.
The beep when you hit a key on the front panel is fed into the
audio amp circuits, so it affects all RX audio, which of course will cause
momentary QRM to a RX signal, especially when running digital modes.
Well, you say, just go into the menu and turn the beep off!
Yeah, you can do that, but not so fast! Turn it off and hit another key
and you lose RX audio for the same duration! This is due to the fact that
the microprocessor sends not only a beep signal, but controls a RX Mute line
at the same time! While you can shut off the beep function, you can't shut
off the mute, so it still interupts the receiver audio for the same duration!
The obvious fix, which I have done, is to cut the Mute line track on the
audio PCB. This will completely cure the RX audio problem, however there
is at least one side affect. The most obvious is that you can no longer
mute the main receiver audio (I never use this feature). It also seems
like there might be a little more T/R "pop", but it's slight if so.
Your goal is to cut the line between pin 8 of Q5008 on the control board
and D3014 on the AF Unit board. I used an Xacto knife to cut the PCB trace
on the component side of the AF board just as it leaves Pin 14 of J3029.
ALERT!!!
THIS IS NOT A FACTORY MOD! ALTHOUGH THEY ARE AWARE OF WHAT I DID, THEY
HAVE NOT "AUTHORIZED" THIS MOD, AND MAY NEVER BECAUSE OF THE LOSS OF SOME
MUTE FUNCTIONS. I ASSUME NO RESPONIBILITY FOR ANY DAMAGE AS A RESULT OF
RADIO MODIFICATIONS MADE.
73, Tyler KF3P
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