No audio output from radio system

[dcwang3]

I'm having issues with no audio output from my 92 325i convertible radio system. I had to change out the power antenna and antenna wiring cabling. Both were brand new and BMW parts, no aftermarket. The head unit turns on and it seems like everything is functional but there is no audio output. I have another 87 325i convertible with a working system. I tried both the known working head unit and amp into the non working system, this time I heard some static noise occasionally from the speakers (when ground wire intermittently connected).

Next thing I did was in the known working system, I tried the "non-working" head unit and amp by itself to isolate the problem. The amp works with the working head unit, but when I install the non working head unit into the working system, it doesn't work, no audio output.

So from what I can tell is the speakers and the amplifier is working. The very strange thing is the "non-working" unit doesn't work in the either system and the working head unit doesn't work in the non working system. If the working head unit worked in the non working system, then I would say the original head unit was the culprit, but that isn't the case.

Any one has any insight on this?

[dcwang3]

any suggestions? I'm sort of scratching my head on what it could be, unless its actually the wiring….

[msservices]

Why did you have to change the antenna and antenna cable?

[dcwang3]

I was disconnecting the coax from the power mast and the connector on the mast just crumbled…. It made out of some kind of plastic that has metal pieces in it. The cable connector side has pieces still in the threads that was impossible to get out. So I changed the entire cable rather than splicing it.

I was reading around and found some information about the CM5908 not outputting any sound, and that it could be the capacitors on the PCB. I opened up the head unit and it looks like some of them are leaking slightly. This may be the cause, but that doesn't answer why when I put a working head unit in the system, it doesn't work.

[msservices]

I say you have more than one issue
One is the head unit, another is a connection/wiring issue in the non working system.
Otherwise, you simply have a compatibly issue between the two cars you are swapping parts between

[dcwang3]

I know the amplifier works because I tested it in the working system. I can tell the speakers are working (I think it's working) because when I intermittently hook the GND, I can hear some high pitched static noise very shortly.

I guess one thing I can do to make sure that it's not the cable or mast (even though they are brand new) is put a cassette tape and try that?

[msservices]

I was just going to say...try a cassette tape.