CDM1250 Servicing
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CDM1250 Servicing
I got a VHF CDM1250 that refuses to turn on, I have tested many mobiles to the same power source and they have no problems powering on so its the radio. The power source is always on so there should be no issues with the ignition sense. I wondering if I should check inside the radio for a loose connection but I cant figure out how to lift the board out of place to get underneath it. I can open the radio to the board but im stuck after that. Any ideas or suggestions?
Re: CDM1250 Servicing
Do NOT force taking the radio circuit board out, you will possibly destoy it.
FIRST. Have you put an ignition sense cable on it and tried to power it up? If the ign sense circuit fails, sometimes the radio WILL NOT power up without having the ignition sense powered. Usually caused by welding on the chassis of the vehicle while radio has power or jump starting.
SECOND. There aren't any components underneath that could come loose usually but here goes:
Remove front control head and flex.
Remove the flex 'filler' plug that rest in the other set of contacts.
Remove top plastic cover.
Remove metal cover and all screws in it.
Remove rear accessory connector adapter which plugs into circuit board.
IMPORTANT: The RF PA has a tendency to 'glue' itself to the chassis. GENTLY heat the circuit board around the area of the RFPA backside to warm the insulator pad and GENTLY pry the circuit board up from the front edge with your fingers. It will unstick itself eventually. If you pry the circuit board up and the RF PA is still attached to the metal chassis, put the whole mess back together and ship it to Mexirola with a check for $224.....
FIRST. Have you put an ignition sense cable on it and tried to power it up? If the ign sense circuit fails, sometimes the radio WILL NOT power up without having the ignition sense powered. Usually caused by welding on the chassis of the vehicle while radio has power or jump starting.
SECOND. There aren't any components underneath that could come loose usually but here goes:
Remove front control head and flex.
Remove the flex 'filler' plug that rest in the other set of contacts.
Remove top plastic cover.
Remove metal cover and all screws in it.
Remove rear accessory connector adapter which plugs into circuit board.
IMPORTANT: The RF PA has a tendency to 'glue' itself to the chassis. GENTLY heat the circuit board around the area of the RFPA backside to warm the insulator pad and GENTLY pry the circuit board up from the front edge with your fingers. It will unstick itself eventually. If you pry the circuit board up and the RF PA is still attached to the metal chassis, put the whole mess back together and ship it to Mexirola with a check for $224.....
Re: CDM1250 Servicing
I have both GM300's and CDM's interfaced into TELEX VEGA IP-223 remote IP adapter panels
and running C-soft console software.
Most of the time we never use the console software or interface and simply use the conventional
radio microphones. We built 3 in square individual small black boxs that route audio outout to an external speaker and which is located in the best location for the operator to hear. The box also has a
small toggle switch that allows the radio audio output to be switched between the speaker
or a 5 w 8 ohm resistor load. There is also a 3.5mm headphone jack with a small dropping resistor ( i think 1K ohm)
and we use inexpensive stereo headsets to monitor receive audio if needed. The black box is mounted
in front of the operator for ease of operation. The switch basically just mutes the external speaker
but allows the headphone jacks to always be on.
We have found this to very flexible and easy for any operator to understand and allows us full use of the radios while minimizing the ambient noise.
This also frees up the Telex console for patching or linking as needed but has rarely been needed.
and running C-soft console software.
Most of the time we never use the console software or interface and simply use the conventional
radio microphones. We built 3 in square individual small black boxs that route audio outout to an external speaker and which is located in the best location for the operator to hear. The box also has a
small toggle switch that allows the radio audio output to be switched between the speaker
or a 5 w 8 ohm resistor load. There is also a 3.5mm headphone jack with a small dropping resistor ( i think 1K ohm)
and we use inexpensive stereo headsets to monitor receive audio if needed. The black box is mounted
in front of the operator for ease of operation. The switch basically just mutes the external speaker
but allows the headphone jacks to always be on.
We have found this to very flexible and easy for any operator to understand and allows us full use of the radios while minimizing the ambient noise.
This also frees up the Telex console for patching or linking as needed but has rarely been needed.