sjg1138

I've spent a bunch of time trying to track down a related thread but to no avail. Maybe someone out there can help me out.

I have a 1999 996 cabriolet with what I believe is the "hifi" option. it has a CR-210 cassette radio along with a Nokia 49134 Amp and a CD changer in the Frunk.

So the issue is that there is a loud crackling sound that comes out of the right speakers. I think it is coming out of all of the right (passenger) speakers and it does not vary with the Input selected on the Radio. If fact the volume can be turned all the way down and the same noise will come out.

I've checked and cleaned all the connectors at the radio and the amp but I'm still getting the noise. I pulled the speaker that is making most of the noise and tested it outside the car. It is working fine.

Anyone have any ideas? I'm not sure if its the radio or the amp. I've pulled the amp and am about to try testing it outside of the car to see if i can reproduce the problem....

Any thoughts would be greatly appreciated. Very frustrating and I'd like to keep the original equipment if possible. Love the retro look....

white out

bad speaker component?

sjg1138

I brought the speaker inside and hooked it up to a stereo. Sounds great.

Cuda911

I think you just have a loose wire to the speaker. Since you checked the connections at each end, maybe there's a place where the insulation got pinched (or munched by a rat) and is grounding out on something.

Hurdigurdiman

What about changing the fuse that controls the sound system . A loose or bad connected fuse could cause a crackling.. BUT you say only on the passenger side. So I can't see my suggestion solving the problem. If it was a loose fuse all the speakers, passenger and drivers side, would be sending out the crackle I would think. I can't see the aerial being the cause as that would effect all speakers. What about the slider on the radio which takes the speakers balance from one side to the other of the car, could the contacts on that be the problem? Hey I have no idea on how to fix it if it was, but just throwing a few thoughts your way. I have the same year and model 996 as yours. A 6 CD changer in the frunk. A 4 cd in the car under the PORSCHE CDR 220 radio. If it is any consolation to you, the radio on mine is not very clear only on some stations. I usually play the cds from the frunk as they are really clear. I haven't tried a cd in the 4 bank inside the car as yet but should do. Good luck with your problem.

sjg1138

So I yanked the 6-channel M490 AMP with the idea of testing it out of the car. Its amazing how little information there is about the amp. I have found wiring diagrams for the connectors into it but am having a hard time deciphering them. There are two connectors on it, a black one and a blue one. The blue one is for speaker outputs and the black is for line level inputs etc.

The messed up thing is that the Black connector has NO pin numbers on it. Makes it really hard to use a wiring diagram when you dont know which pin is which.

A couple of questions I have are:

1) which are the power and ground pins?
2) is there a separate power and control pin ? Which are they?
3) how can I tell if the Amp is ON?
4) How are the pins (from which direction) on the Black connector counted? Where in the four possible places is pin One?

Any help would be greatly appreciated. Getting frustrated over here. Getting the Amp working on a bench should be easy....

sjg1138

I finally figured out the wiring diagram and got the amp working on its own. Pins 1 and 2 are ground and power respectively on the big Blue connector and pin 7 on the Black connector is the Control (turns the amp on when +5 is put on it). Looking at the back of the Amp with the Black connector on top and the Blue connector on the bottom, Pin 1 of the Black connector is in the lower right. The pin #s count up from there. I tested one channel and it seemed to be fine (connected my phone to an input on the Blue connector and a home speaker to an output on the Blue connector). Five more to go.

sjg1138

Its looking more and more like a problem with the wiring harness - maybe at the black connector that plugs into the Amp. Thanks for your input so far guys.

Any suggestions for testing the wiring harness from the Radio Line Out connector to the Amp Line IN connector? I'm thinking a probe stuck in each end (one inside the car and one in the frunk) with an Ohm meter in between.

The problem seems to be isolated to the Front Right speaker.

sjg1138

Took out the CR-210. Front Right channel is bad... Anyone have an old Radio lying around they wouldn't mind parting with?

sjg1138

Found a "new" head unit on Flea bay. Problem solved!