GR300 mic issue

[Essexsaxo]

Hi,

I have recently put together a motorola GR300 (2 x GM300) repeater using an Id-o-matic III as the controller, I've recently noticed rah when the repeater is in operation the hand mic that is plugged into the TX radio is
live, is something connected incorrectly? I am using the rear 16pin accessory connector to connect to the Id-O-matic. Do I need a desk mic to overcome this??

[Will]

Check the DC voltage at the mic line on the 16 pin connector. It should be way up at about 9 volts.

If not the mic is not switching correctly.

"Do I need a desk mic to overcome this??" No the mobile mic should be OK.

[MassFD]

As I remember the GM300 the front and rear connectors share the same audio componants and PTT line so if you sre keying from the rear connector the front connector will be live.

Only way to solve it is to use a mike that breaks the audio path inless keyed, I think the desk mike does that. Or use a CDM as transmitter as they have independant audio paths,

[Essexsaxo]

Thank you very much for your replies, I just had a thought, is there any internal jumper settings that need to be made for repeater operation?

[Essexsaxo]

Hi guys, just a quick update, the problem was solved by using a desk mic, the mic is no longer
Live when the repeater is in operation.

[tsunami_australia]

This is handy to know since I'm about to make a cross-band repeater from a VHF-HI M120 and T band GM300 in our house and obviously don't want private conversations in the house being aired to the public. I already have and use a desk mic for the T bander (my primary radio) but this means I will need to remove the fist mic from the VHF to stop the same from happening and perhaps patch the desk mic as needed.

I thank you folk in advance for the information ahead of time.