cdm 1550 no receive audio

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arlojanis
Posts: 1055
Joined: Mon Jan 28, 2002 4:00 pm

cdm 1550 no receive audio

Post by arlojanis »

I have a CDM with no receive or beep audio and there is no 6.4 vdc between the speaker wires and ground. Does this mean a bad output IC ?
"The world runs on radio."
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jackhackett
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Joined: Tue Jun 10, 2003 8:52 am

Re: cdm 1550 no receive audio

Post by jackhackett »

Yeah, about a 99.9% chance that's what it is.

It's not a low band model, is it?
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arlojanis
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Joined: Mon Jan 28, 2002 4:00 pm

Re: cdm 1550 no receive audio

Post by arlojanis »

It is VHF. I have noticed that pin 8 unmute is not going above 6 volts. I am thinking a bad IC may be loading pin 8. A good radio always has the voltage on the speaker wires.
"The world runs on radio."
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Will
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Joined: Tue Sep 04, 2001 4:00 pm

Re: cdm 1550 no receive audio

Post by Will »

arlojanis wrote:I have a CDM with no receive or beep audio and there is no 6.4 vdc between the speaker wires and ground. Does this mean a bad output IC ?
The radio has a "bridge audio amplifier", and you will not see the voltage on the speaker pins unless the amp is active. That is when the receiver is active. Check for audio prior to the speaker amp circuit. Volume control, handset pin in the mic jack.......
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