CDM 1550 LS+ - dead head?

[ve1gln]

I have a CDM 1550 LS+ that when you turn it on, you hear a beep, then it cycles, beep.....beep.....beep...etc etc

Is this a head problem? firmware? if I throw another head on it, it works.

Hoping maybe this is something that can be fixed.

Thanks

Glen

[d119]

I had one that did the same thing, turned out to be the control head.

[RADIOMAN2002]

Make sure it is a correct head, there are program jumpers on the board that tell the radio what kind of head to expect. If you put a wrong head as in this case one from a CDM-1250 you will get that error too.

[ve1gln]

Make sure it is a correct head, there are program jumpers on the board that tell the radio what kind of head to expect. If you put a wrong head as in this case one from a CDM-1250 you will get that error too.

Do you know where the jumpers are and what the setting should be?

Thanks

Glen

[ve1gln]

Anyone have CDM1550 head they would like to sell at a reasonable price?

PM me please.

[RADIOMAN2002]

I just realized that my last post didn't make it. So I will try again, first is the radio an AA model, what is the model number and Tanapa numbers. The head for a CDM1550 is GCN6114, and for a 1250 is GCN6113. To make a CDM1250 head fool the micro-processor in the radio you have to move r8057 to r8058 position and r8053 to r8052 position. You wont have control over the left and right buttons that takes another resistor r909 at 43k. The leds are not there so the button won't light but they will work if programmed.

[RADIOMAN2002]

I was wondering if you were able to fix your radio. I ran into a similar problem this morning while repairing a box load of CDM radios. The radio originally worked, I converted it from rear to front mount and the radio started giving me the same error of beeping and then cycling on and off. After about 20 min of testing I found that when I hooked up the accy plug for ignition sense I must have bent one of the pins over and it was touching another. After I straightend the pin out the radio worked fine. You might want to look at the accy pins on the rear of the radio

[ve1gln]

Radioman,

We tried it on a known working chassis as well and it's still dead.

Thanks for the input though.

Glen

[ve1gln]

Found the problem, well sort of... Seems the filtered B+ going to the head isn't there... comes into the radio, but doesn't make it to the head... if I jump 12V to the head, everything light up fine and works as it's suppose to.

Anyone know if there is a fuse or diode that I should be looking at someplace on this beast... Maxtracs were a lot easier to work on

Thanks

Glen

[jackhackett]

FLT_A+ to the control head does have a "fuse", which may be a chip component or a thin circuit board trace depending on which circuit board you have.

If you don't have access to a detailed service manual, let us know the radio model number or main board number, or at the very least what band and power level it is, and I'll see if I can tell you exactly where it is.

[ve1gln]

AAM25MHF4DP5AN

54865T-03-C
8485249Z05_0

220 Mhz 25W

Thank Jack.

Glen

[jackhackett]

I couldn't find that exact board, here are a couple of pictures that that might be close enough.
They show the area around the control head connector on the top of the board.

The fuse in the first picture should be a a small chip type, probably will have a grayish color to it. The resistor in the second picture should actually be an empty pair of solder pads, the circuit trace loop is the fuse and when it opens the pads are provided so you can solder in a chip fuse. It should use a 3A fuse.

[ve1gln]

Thanks Jack,

That was it... I wonder why that is fused, maybe because FLT_A+ is available on the MIC plug...

Thanks again for the help.

Glen