CDM1250 No Backlight or Other LED's

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apd242
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Joined: Sun Dec 11, 2011 5:05 pm

CDM1250 No Backlight or Other LED's

Post 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
Jim202
Posts: 3609
Joined: Sun Sep 09, 2001 4:00 pm

Re: CDM1250 No Backlight or Other LED's

Post 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
jcsradio
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Re: CDM1250 No Backlight or Other LED's

Post 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!
Jim202
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Joined: Sun Sep 09, 2001 4:00 pm

Re: CDM1250 No Backlight or Other LED's

Post 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
Jim202
Posts: 3609
Joined: Sun Sep 09, 2001 4:00 pm

Re: CDM1250 No Backlight or Other LED's

Post by Jim202 »

Well did you repair the radio?

Did you find the information you were looking for?

Jim
wvfc
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What radios do you own?: cdm 1250,vertex 180

Re: CDM1250 No Backlight or Other LED's

Post by wvfc »

I am Having the same issues any help would be greatly appreciated
New Guy Learning, Please forgive me :o
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jackhackett
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Re: CDM1250 No Backlight or Other LED's

Post 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?
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FMROB
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Re: CDM1250 No Backlight or Other LED's

Post 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
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jackhackett
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Re: CDM1250 No Backlight or Other LED's

Post 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.
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fineshot1
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Re: CDM1250 No Backlight or Other LED's

Post 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.
fineshot1
NJ USA
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