I have an HMN9030A speaker mic that works fine with my GTX 900, but won't key the transmitter on my GP300 (220 MHz). If I key both the radio PTT and the mic, the mic works fine. I measured the resistance across the smaller plug, and it drops as expected when I squeeze the PTT on the mic. Two different aftermarket mics work on both radios. It looks like the plugs have the same dimensions. Am I overlooking something?
Jeff
Screwey speaker mic problem
Moderator: Queue Moderator
The GTX and the GP300 may be the same radio platform, as for form factor, but the methods used to key the radios and pass TX audio are probably configured differently, one using the tip for TX/mic audio and the other using the ring for TX audio and the tip for TX only.
But the other gentleman is also correct in that the two spkr/mic assy(one piece) does have problems with wear, and the contacts do lose their 'springyness' and fail to make proper contact.
I've repaired close to 100 of these radios with the same problem.
The solder connections also take a beating due to the mic cord stressing this point on the board, so you get minute cracks around the solder joints and this also causes cut-outs.
The radio should have been designed somewhat like the HT600/MT1000(Genesis) radios as that format is far less likely to cause the troubles the P110/GP300/GTX and the like experience.
Hell, even the Visar's side connection was a better design, but then again, we are talking Radius models over Circle-M branded gear for the commercial/P.S markets.
But the other gentleman is also correct in that the two spkr/mic assy(one piece) does have problems with wear, and the contacts do lose their 'springyness' and fail to make proper contact.
I've repaired close to 100 of these radios with the same problem.
The solder connections also take a beating due to the mic cord stressing this point on the board, so you get minute cracks around the solder joints and this also causes cut-outs.
The radio should have been designed somewhat like the HT600/MT1000(Genesis) radios as that format is far less likely to cause the troubles the P110/GP300/GTX and the like experience.
Hell, even the Visar's side connection was a better design, but then again, we are talking Radius models over Circle-M branded gear for the commercial/P.S markets.