Bundy

I too have had the periodic static problem with my radio. It usually resets itself when you turn the car off and back on but not always.

Anyway, I have noticed a definate connection between this and the a/c unit. If I start to hear static (it always starts slow and builds to complete shut down) I turn off the whole climate control system and after it finally shuts off (20-30 seconds) the static will go away and the audio will begin working again. At this point, I can usually turn the climate back on and everything will be fine. The static also seems to occur more frequently when the fan is set to the higher settings or on auto and the fan blows real hard at first.

I wonder if there is some undervolt problem that causes this to happen and shutting down the climate reduces the electrical load on the other electrical systems.

Well this is something I noticed on my car. I wonder if anyone else has made this connection or would try the fix when the static starts.

Barry45RPM

I too had the static & shut down problem twice & ascociated it with the cold weather of winter (a temp sensitive component?). The dealer made the software update in very early spring & have never had it again.

Another bug was a sudden high pitch whistle/scream & then radio shutdown. I had that once before the updat & have had NO problems since then.

BoSoxFan

I wonder if they did something in addition to the software update. Electric motors can induce noise (static) in an audio component. The a/c system must be full of motors. Perhaps they also replaced a bad filter which was supposed to prevent the interference.

I think that the reason MB went to fiber optics for the A/V system is because a fiber optic cable is immune from interference from all of the other electrical and electronic devices in the car.

redlands40

So the interference cannot be from the a/c, as fiber optic cables have been in since the 2003 model

BoSoxFan

I didn't know that. When did they go to optical? It's possible that the noise is being induced in the signal path after the transceiver does the optical-electrical conversion, or in the power lead which is copper, or in the speaker lead which would most likely also be copper. It could even be a bad ground in the electrical lead. Of course, it may be a software problem also.

BudC

I believe Mercedes Benz went with fiber optics for several reasons.

First, the German government has been dictating the implementation of changes to help the environment. The reduction in the use of copper is one of them. Mercedes isn't alone in this. BMW has that wonderful little invention called iDrive.

Second, going to fiber optics reduces cost significantly.

Finally, it also reduces weight.

Frankly, I prefer the good old fashioned way with real switches and copper wiring, i.e. no programming!

BoSoxFan

Those are all valid reasons, except possibly for cost. In the data communications world, fiber cable costs about the same as copper cable; however, connectors are more expensive although the cost is continually coming down and getting close to that of copper and electronics are more expensive but also continually decreasing. A fiber optic cable requires a transceiver to connect to an electronic device and that negates some of the potential weight and cost savings. The military is going to fiber in a big way because of both the freedom from interference (they use a lot of electronics and electrical devices as well especially in the RF range) and, more importantly, security. Whatever MB's reasons, I think it was a good decision.

BoSoxFan

P.S., I like the old-fashioned way, too. I miss the days when I could fix just about anything on my car with a standard set of hand tools and the only electronics I needed was a strobe, dwell meter, and voltmeter. Unfortuantely, in today's world you can't get away from programming, no matter what the media.

konigstiger

Curious, has your dealer performed bulletin P-B-8-85/325b? If not, pm your email address and I’ll forward a copy.

my E430 rocket

maybe the fan is producing some sort of static electricity

Bundy

The static we are getting does not sound like electrical interference. It sounds like digital noise. I am very into high-end audio and have experienced similar sounding problems when digital bit streams are not decoded properly.

I suspect that the power supply to the head unit gets insufficient voltage and the computer that converts the bitstream quits operating correctly. Turning off the A/C reduces the cars electrical load and restores the proper power requirements to the head unit. It takes a minute or so after turning off the A/C for the correction to occur so I don't think interference is the issue as it would then stop when the blower stops. It takes longer.

This is just a theory. I have no real test that proves this. It just is very similar to problems I've seen in my home audio system.

BoSoxFan

I've had weird things happen with bad CD's and bad CD players also. That's one reason why I like to play my original Living Stereo and Mercury LPs through tubed amplifiers.

Oh well, your theory makes sense but it's probably time to get the dealer involved.

Brav

wow, that actually makes sense. probably something to that effect.