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cdm 1550 no receive audio
Posted: Thu May 01, 2014 9:37 am
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 ?
Re: cdm 1550 no receive audio
Posted: Thu May 01, 2014 11:06 am
by jackhackett
Yeah, about a 99.9% chance that's what it is.
It's not a low band model, is it?
Re: cdm 1550 no receive audio
Posted: Thu May 01, 2014 11:14 am
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.
Re: cdm 1550 no receive audio
Posted: Fri May 02, 2014 12:03 pm
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.......