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Problem with SM30 desk mic on Icom IC 7300.

ClaimJumper

Active Member
Mar 31, 2024
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I have an icon sm30 desk mic hooked up to an Icom IC 7300 and when I key the mic it makes a noise inside the radio. Kind of like a relay bouncing back and forth very quickly. Only while the switch is in motion. Is anybody familiar with this problem?
 

The problem has to be the mic switch. It seems like to me. All other microphones work fine. I was just curious if this was an issue for anyone else with the same microphone.
 
I'd check continuity with a multimeter between pins 5 and 6 of the mic plug while the mic is keyed to rule out the mic's switch.
Maybe an rf issue? don't know what mode you're on try turning the power and or mic gain down and see if either make any difference.
 
I'd check continuity with a multimeter between pins 5 and 6 of the mic plug while the mic is keyed to rule out the mic's switch.
Maybe an rf issue? don't know what mode you're on try turning the power and or mic gain down and see if either make any difference.
Wide open between pin 5 and pin 6. Power or mic game make no difference. The microphone works, and I'm using it. The action of the switch throw is what is causing the noise inside the radio. That noise stops when the microphone fully keyed. The point between receive and fully keyed is where the noise is. I use the lockdown key instead of the push to talk key. It's a different switch, and a shorter throw. I hope that makes sense. The blue switch is the lockdown. The black switch is the push to talk switch which seems to be the culprit. I believe it's just a bad scratchy switch.
 

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