K3 Using IC-SM5 Mic

[w0ih]

I'm trying to get my Icom IC-SM5 mic to work with the K3.  I've setup the "FP:L Bias" on the K3 and there is 4.98 volts on Pin 1 of the K3 mic connector.  No output from the rig at all (varied the pot on the bottom of the mic and the rig mic gain).

I would think that 5v should be sufficient for the SM5 mic.

I tried putting in a 1k resistor from pin 6 (8v) to a 2.2uf cap, but then I just get feedback (full output) into a dummy load.

Anyone have any ideas?

Mike

[w0ih]

Barry, K8LEF contacted me off line with a solution that worked.

He is using an Icom IC-SM5 microphone as well.  Solution was to bypass the internal microphone amplifier.

Remove the bottom cover from the mic and disconnect the red (pink?) wire coming from the mic (from the Pad marked ECM+) and disconnect the white wire from the incoming cord (from the pad marked OUT).  Solder these two wires together and insulate the connection so it doesn't short to ground.    You do need to turn on the Bias for the electret mic.  Set it for "FP.L bias".  Mic gain works great around 20 to 25.

The PTT line does need to be moved from pin 2 to pin 6 to get the PTT to work.

Hope this helps anyone else searching for a similar solution.

Thanks Barry!

Mike
  W0IH