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CDM1250 No Backlight or Other LED's

Posted: Sun Dec 11, 2011 5:40 pm
by apd242
Hello. I purchased a CDM1250 VHF which seems to be working perfectly, with the exception of the back lighting and LED's above volume knob do not work. I verified the settings in the CPS, assigned a button for back lighting, tested the radio in both remote and desk mount configurations; all with negative results. Does anyone know of someone who could fix this for me? I read some previous posts which report some sort of "fuse" type board which needs replacing, but I am not technical enough for that. Any and all help would be greatly appreciated!

Thanks in advance!

Mike D
New Jersey

Re: CDM1250 No Backlight or Other LED's

Posted: Mon Dec 12, 2011 4:02 am
by Jim202
apd242 wrote:Hello. I purchased a CDM1250 VHF which seems to be working perfectly, with the exception of the back lighting and LED's above volume knob do not work. I verified the settings in the CPS, assigned a button for back lighting, tested the radio in both remote and desk mount configurations; all with negative results. Does anyone know of someone who could fix this for me? I read some previous posts which report some sort of "fuse" type board which needs replacing, but I am not technical enough for that. Any and all help would be greatly appreciated!

Thanks in advance!

Mike D
New Jersey



There are a number of things that could be the cause of your problem. This includes the micro that is inside the control head. The micro supplies a control voltage that turns on a transistor and op amp to control most of the back lighting. Without going into the head with a voltmeter, your not going to locate the exact cause of the problem.

If you can send me a good email address, I will see what help I can be.

Jim

Re: CDM1250 No Backlight or Other LED's

Posted: Thu Oct 25, 2012 11:55 am
by jcsradio
To renew this thread, I am having the same problem. apd242 or Jim202 - any thoughts on how this was resolved to help me out? Thanks!

Re: CDM1250 No Backlight or Other LED's

Posted: Fri Oct 26, 2012 4:02 pm
by Jim202
jcsradio wrote:To renew this thread, I am having the same problem. apd242 or Jim202 - any thoughts on how this was resolved to help me out? Thanks!


Check you PM.

Jim

Re: CDM1250 No Backlight or Other LED's

Posted: Sat Oct 27, 2012 1:53 pm
by Jim202
Well did you repair the radio?

Did you find the information you were looking for?

Jim

Re: CDM1250 No Backlight or Other LED's

Posted: Sat Feb 24, 2018 11:05 am
by wvfc
I am Having the same issues any help would be greatly appreciated

Re: CDM1250 No Backlight or Other LED's

Posted: Sat Feb 24, 2018 10:54 pm
by jackhackett
What is the model number?
Do you get a power up tone?
Do you get button press tones?
Does the radio receive and transmit?
Is the LCD out?
Are all of the LEDs out, backlight and scan/tx/rx indicators?
Do you have another CDM1250 that you can swap heads with?
What is your skill level, are you comfortable taking voltage measurements on small surface mount components?

Re: CDM1250 No Backlight or Other LED's

Posted: Mon Mar 05, 2018 3:35 pm
by FMROB
Take the head off, chances are the circuit board is not seated in the plastic of the control head housing. There are little clear clips around the perimeter and the boards often pop out, which will cause button, display, volume, and light issues.


Rob

Re: CDM1250 No Backlight or Other LED's

Posted: Tue Mar 06, 2018 12:00 am
by jackhackett
FMROB wrote:Take the head off, chances are the circuit board is not seated in the plastic of the control head housing. There are little clear clips around the perimeter and the boards often pop out, which will cause button, display, volume, and light issues.
Rob


A loose control head board shouldn't cause volume or backlighting problems, only the LCD and buttons, which rely on pressure contacts, should be affected.

Re: CDM1250 No Backlight or Other LED's

Posted: Tue Mar 06, 2018 5:23 am
by fineshot1
It has been quite awhile since i was inside of a CDM but I do think it may have been a regulator issue in the control head.
There are about 2 or 3 regulators in CDM control heads that may be the issue.