CDM1250 No TX transmit out of front mic jack

[abrasowski]

I have a used CDM1250 that I picked up
I have plugged in numerous mics (hand mic, desk mic, etc.) into the front jack and none of them will cause the radio to transmit. The red tx light will not turn on nor will any audio be transmitted. It receives audio and otherwise works fine.

I tried checking the programming but nothing looks like it is out of the ordinary.
On a side note, when I received the radio it had a 16-pin connector hook to 1.a serial/printer size connector and 2.a brown wire to the back of the radio above the rear 20-pins.

Any thoughts?

[HLA]

have you checked programming to see if everything is set to recieve only?

[abrasowski]

You mean a "master" receive only? I don't know where that would be.

On an individual channel basis yes, most channels have a tx and rx freq. Some are rx only.
On the Rx only, usually you would get a solid tone when you try and key up the mic. On this radio there is no tone aka. the radio does not acknowledge the mic is trying to transmit.

[escomm]

Replacing the mic jack is not very difficult but does require a soldering iron

[abrasowski]

I don't think the physical jack is bad for two reasons-

1. I received two radios in this lot, (obviously used for data of some sort or repeater/phone patch because of the control cables on the 16pin connectors) and both radios exhibit this problem.

2. After a MDC1200 ID appears on the radio's screen, if I hit the PTT on the palm mic, it clears the id off the screen (as it normally does when you are about to TX to let you know what channel you are about to talk on- but will not actually transmit

What is a wire coming out of the back of the radio right ABOVE the 20 accessory pins used for?? It is in 1 out of 5 slots

[HLA]

someone else help me out here but i remember on some radios when they are converted for data they can't be changed back? is that the cdm's?

[abrasowski]

Here's an update...
The radio when I write it for the first time after changing the programming says something along the lines of:
"the radio is programmed for a mult-function/dtmf mic but no functions are programmed, software will continue to write but you will not have access to these functions"

That's what I remember, it's definitely not word for word but has anyone ever seen this?
I'd be willing to email over the codeplug file to someone if they want to take a look. It is for a VHF CDM1250 45w

[abrasowski]

Problem Solved...somewhat

For those that may stumble accross this thread looking for help. I ended up swapping the control head on one of the cmd1250's with a known good working radio's control head (lcd screen, speaker, and circuit board). Well lo and behold it now transmits! So sorry to the guys who I said its probably not the mic jack or control head
I do want to check whether or not it is the actual Mic JACK soldered onto the circuit board, or whether or not something is wrong with the circuit board itself. Upon inspection the 10? solder points of the mic jack look to be ok and making good connection.

thanks for the help everyone. I will update this thread when I find out more

[wavetar]

Judging by the funky rear connector assembly they came with, it sounds to me like they may have been setup for SCADA or similar use, and local techs may have simply removed a resistor to disable front mic jack functionality. If your 'good' CDM board is the same version, you may be able to do a physical inspection & see if a component appears to be missing. In particular, resistor R0843 & transistor Q0843 are likely culprits to have been removed.