Ack! You sure you want to do this, Don? Pin 17 is bipolar drive, so you would be shorting a relatively high-current output (25 mA per spec) to ground. That has a good potential for letting smoke out of the MCU.

IF you do this, I HIGHLY recommend a current limiting protection resistor in the circuit. A few hundred ohms should do, but might also affect muting operation...

On Dec 9, 2004, at 10:41 AM, W3FPR - Don Wilhelm wrote:

For something more temporary, an open collector transistor connected to pin 17 of the MCU (Control Board U6) would do the job for you - drive the base of the transistor with 3 to 5 volts to turn it on when you want the K2 muted. A 2N2222 or similar should work just fine.

-Jack Brindle, W6FB
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