CDM1550 VHF overheating

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wcu02mpa
Posts: 58
Joined: Mon May 12, 2003 5:08 pm

CDM1550 VHF overheating

Post by wcu02mpa »

I have a CDM1550 VHF (non-LS) AAM25KKF9AA5AN. It is recently acquired. It reads and writes fine, transmits and receives fine. The problem is when I plug it in the heat sink gets hot, even when not transmitting. Any ideas?

I have never seen this before.
I may not fire the first shot, but I will fire the last one.
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d119
Posts: 3538
Joined: Tue Mar 19, 2002 4:00 pm

Re: CDM1550 VHF overheating

Post by d119 »

Probably a failed or failing PA transistor.
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tdats
Posts: 172
Joined: Tue Jun 10, 2008 8:23 am
What radios do you own?: Mostly Motorola

Re: CDM1550 VHF overheating

Post by tdats »

If there is anything connected to the accessory connector, make sure that none of the speaker output pins are grounded. I had a bus radio do that do me on a swap out one time, the speaker they already had was grounded.
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jackhackett
Posts: 1518
Joined: Tue Jun 10, 2003 8:52 am

Re: CDM1550 VHF overheating

Post by jackhackett »

Is it a remote mount? If it is, open the head, and put some insulation between the circuit board and speaker terminals. A couple layers of electrical tape should do. In the remote mount kit they put an exposed ground pad on the board right under where the speaker terminals are and there is not much clearance so it shorts and causes the radio to get very hot, eventually killing the radio.
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