murman

Hi there. Have a 2004 W211 (well, S211 actually) that has an audio bug that's driving me crazy.

Earlier this year, purchased and installed a used CD changer, after which an audio problem started propping up that I thought HAD to be due to the replacement changer because the audio problem does not appear when listening to the radio or auxilliary input. Did not have this problem with CD audio until after the replacement CD changer was installed.

Hard to describe exactly what's going on, but intermittantly it's as if the CD audio looses its top end and almost sounds mono, and then flips back to normal. It's really frustrating.... sometimes there's no problem for an hour, and then it flips back and forth from good to bad occasionally.

Replaced the changer again, thinking it was defective, and lo and behold the second replacement changer is exhibiting the same problem.

What are the odds of that? Can the glitch instead be related to another component in the MOST loop, AGW perhaps? See, I'm thinking not, because the audio path for the auxilliary and radio flow through the same MOST loop, if I understand the loop correctly.

Radio signal is processed in the AGW, IIRC, whereas the auxilliary audio flows out from the COMAND unit to the AGW.

So, long story short, could the bug be somewhere else, or did I just win (lose) the lottery and happen across two CD changers with the same bug in them?

Any help GREATLY appreciated.

murman

No electronic gurus out there who can speak to this issue, even conceptually?

Richard

Firstly, ensure that
a) The COMAND unit has had the MY2007 firmware update done (I don't know what the equivalent is for USA COMAND) - dealer should know if there have been any firmware updates since your car was new
b) Ensure the AGW has the latest firmware - there was an update in 2006 - thise again needs Star Diagnosis the dealer computer system
c) Ensure that the AGW was configured to have the CDC on the fibre optic MOST ring.

At least at that point you know the system has latest firmware and is configured correctly

Richard

Skylaw

And last, be sure nothing is causing a fiber optic cable to kink too tightly - especially if there is something pressing against one to cause a "kink" or too tight a curvature in the cable.

You could lose audio quality if this is happening; and you could have static as well.

Also be sure all of your fiber optic leads are tightly plugged in.

jazzphile

Murman,

I'm going to take a guess at your problem. I have just installed the Dension Gateway 500 in my Mercedes SL500. It's working perfectly, but I know the sound you are talking about.

When I have my IPOD playing, and I enable my telephone to make a calll via bluetooth, before I actually make the call, while dialing but before sending, my stereo has the same "mono", low fidelity type sound.

I wonder if it has anything to do with your bluetooth or phone interfering with the audio system? See if you can correlate it to your telephone in some way.

Jazzphile

murman

Thanks for your reply, Richard.

a) think this was done when I added the first CD changer awhile ago. Next time I'm in, I'll ask the dealer.
b) will ask for this to be checked.
c) this has been done.

M

murman

Hi Skylaw. Wouldn't a loose fibre lead or tight/kinked fibre impact the entire sound system, including radio and aux input?

It's only sound from the CD player that's the problem...

murman

Hi Jazzphile. I did add the "puck with tail" some time ago, but I usually don't have my phone paired with the puck (wife usually does though).

As far as I can tell, there's no correlation with the phone system operation, as I get the buggy sound even if there's no phone paired with the puck.

Skylaw

It may not affect radio or AUX, since that's built into the H/U. It could affect other components.

murman

But doesn't the aux sound output flow to the AGW via MOST, which goes from the COMAND unit through the CD player and then to the AGW?

Now that I think of it, isn't the radio tuner actually housed in the AGW?

jbondox

tuner is in the gateway. if the cable was kinked it would affect everything. it could also be the old telaid system

murman

Yikes... diagnosing this is going to be even more expensive than the two replacement cd changers I've bought so far...

Richard

I'd go round looping out each component and seeing if that causes the problem to go away. (Having done what I suggested above first ;-) )

You can get MOST looping tool to make this easier. If you can't find one in Canada, try this: -

http://www.comandonline.co.uk/most-loop-tool.html

Richard

murman

Just might have to do that. Thanks for the suggestion.

mmalrai

well i have a w211 200 k 2004 and there is a problem with the CD changer i guess . it is a 6 cd command and it gets jammed by replaying the same song over and over again and not shifting . sometimes it works fine but it jams again ! btw the cd's are not faulty coz i tried several ones . wts seems to be the problem!

Richard

Are you sure you are just not switching it into Repeat Track mode ? (I can't remember how you do that on the COMAND, but you can)

That would be a strange fault if it just repeats the whole of the same song - as it's not physically moving the disks around, and it is clearly managing to read the whole of the song

Cheers

Richard