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Discussion Starter #1
My car has the hk aps50 optic fibre unit. Since a few days it has a lot of static sound. Even when I play a cd. Anyone know what the problem is?
 

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1999 S500; W140.051; 2003 E320; W211.065; 1973 220; W115.010
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I have an '03 W211 with the Audio50 Command unit and had 'static' issues in the audio system like you describe.

It was sort of intermittent, but it would happen every time the car was driven. It could be made to stop by turning the command unit Off/On a few times. You might try that approach.

I swapped out the Command unit for an Android headunit w/ the analog->FO converter, hoping that the static would go away also. It didn't and instead became a lot worse. I ended up running wires all the way back to the trunk to completely bypass the MOST ring for the audio, which is a hard job.

Some have cited fixing static issues with a software update.

The fiber optic architecture is hard to troubleshoot and mostly relies on 'unit replacement' to find the problem component. You can't 'listen in' at any point in the MOST ring.

In my case, if I were to have continued with the MOST system, I think that perhaps the AGW would be the more likely culprit, but it's hard to know without having tried it.

MB does sell re-furb'd AGW's for around $350 or therabouts, but you'd have to get your P/N and check that as there are a number of variants.

Hope this may help.
 

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Discussion Starter #5
Thank you so much. Think I'll end up rewiring the audio system with regular copper. I don't use the cars navigation, telephone, casette-player or CD-changer/player :) . All I want is music, and streaming isn't even possible.
Only have to find out if there's a possibility to use 6 speakers instead if 4.
Thanks again!
 

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Raytheman,

Regarding the matter of replacing the Command unit with an aftermkt unit and going 'wired audio' instead of MOST system, there are several things to be aware of.

1. You will want to preserve a complete MOST ring. AGW must remain in the system; it's the 'master' and can't be deleted. It's embedded too deep into other things like the SOS/E-call module which is even linked to the AB (airbag controller)!
2. You will need new headunit with internal amp & an additional wire harness that will go from the headunit back to the trunk. Both of these are available from the headunit mfr. I used Erisin and they have pretty good support.
3. Headunit amp has enough power for the front & back door mounted speakers. To power the rear deck speakers, you will need an additional amp and a speaker->line out level converter. My 2003 E320 has 3 rear deck speakers. I got a 'bridgeable' 4-channel amp to power the rear deck speakers in a L/H, R/H, Center Subwoofer config. The center 'subwoofer' config is where the 'bridging' of 2 -channels on the amp make a 'mixed' subwoofer channel.
4. Pulling of wires is down the L/H side of the body conduit in the rocker panel area and requires a 'fish tape' & also electrical contact removal tool(s) to remove the contact terminals from the wire harness as you can't pull a big rectangular connector thru that conduit without damaging something in the mess of wires and POF's (optical fibers) already in that conduit.
5. Must carefully study MB wiring diag; headunit pinout & new harness color codes to make sure all channels are connected right in +/- phase & position as all the contacts have to be put back in the connector shell again. That connector makes with the speaker connector that usually plugs into the AGW. Mine had 7 separate speaker connections; 4 doors & 3 rear deck (14 wires).

Job is straightforward in principle, but has a lot of steps and involves 2 networks; the MOST ring & the new wired audio network.

With good prep/study of the wiring & all components on hand, it's a full day job and involves soldering to tap the new wire harness into the vehicle harness.

Some trunk liner has to be removed. Rear seat & backrest has to be removed. Plastic covers over rocker panel conduit have to be removed at L/H front & rear doors. Trim panel under instrument cluster has to be removed. Mount for aux amp to power the rear deck speakers must be fabbed.

The good news is that the new headunits provide all the functions you want; have a much better display; fast processor, etc.

The electronic stuff is pretty cheap in general. I think it's about $500~$600 for everything.

If you decide you really must go this route, then you can PM me and I will send you info on all the parts I bought.
 

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Discussion Starter #9
Dear Daidnik,
Thank you very much for your extensive answer. Maybe its easier for me to replace the 4 door-spekers, so I only have to pull wires from the doors to the new headunit. The fibre-optic ring will stay untouched than I presume?
The HK-speakers may be not appropriate for the new android-radio
Besides, the SOS/E-call module isn't active for years I've heard. Components can also be excluded with a optic-fiber-loop.
I really appreciate your input on my question. Thanks a lot!
greetings from the Netherlands
 

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With regard to the wire routing to the door speakers, you're still best to do just as I cited before. All speakers are plugged directly into the AGW in the L/H trunk area alongside the rear fender.

Wires already have to be pulled thru the body conduit in the rocker panel area. You don't want to complicate things with L/H & R/H body conduit wire pulls; that would certainly be a worse job.

Like I said before, the job is straightforward in principle, there are just a lot of steps with covers & panels removal; wire pulling; connector shell terminal R&R, etc.

With regard to the MOST ring, some components can be removed, like Command & CD Changer. I don't think the E-Call module can be physically removed/disconnected, but E-Call can be coded to 'Not Present' using Star Diag.

After install of 'wired audio' network, then you can use Star to configure MOST network and view/assess any faults from the change.

Wire terminal removal tools that enable removal & re-install of wire terminals from connector shells:


 

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Discussion Starter #11
Thanks again, I didn't plan to use the speakers in the back. Only the 4 in the doors.
 

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The audio is quite adequate with just powering all the door speakers. This can be done with the internal amp in the Android headunit. What you will be lacking with not powering the rear deck speakers is the 'boom-boom' of the bass which adds a fullness to the sound by projecting the lower bass tones into the top of interior cavity.

You still have to route the 'optional' headunit wire harness with all the speaker outs to the trunk to connect up with the existing vehicle speaker wire harness; the connector that is currently plugged into the AGW.
 

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Discussion Starter #13
I think I will just pull 4 new wires from the doors to the headunit or do you think its easier to pull them from the trunk?
 
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