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W221 s350 radio no sound

mbmb123

Active Member
Joined
Nov 27, 2012
Messages
107
Car
S350 2012 W221
A few months ago the radio would occasionally cut out, no sound. The screen showed the channels as usual but no sound. Switching to CD and back to radio restored the sound. Now it's worse. Radio sounds briefly on startup then cuts out.

It's now colder and damper outside. Several threads have mentioned amplifiers in the boot and water ingress via a "channel" near the number plate. I think they're referring to a channel running around the boot. I can see how water may get in. Is this a possible cause or a red herring?
 
A few months ago the radio would occasionally cut out, no sound. The screen showed the channels as usual but no sound. Switching to CD and back to radio restored the sound. Now it's worse. Radio sounds briefly on startup then cuts out.

It's now colder and damper outside. Several threads have mentioned amplifiers in the boot and water ingress via a "channel" near the number plate. I think they're referring to a channel running around the boot. I can see how water may get in. Is this a possible cause or a red herring?
I think it's your dab module or test antenna, I have the same issue during winter even though I don't use dab. The audio gateway will stop all sound if one related component malfunctions. I went down the wet amplifier route recently by opening the boot lining only to find the amp in great condition with no water. I now bought a Most fibre loop to remove dab and see if I regain audio. People claim that the issues are due to network changes in the UK or that the unit cannot handle more than 100 channels.

Sent from my J8110 using Tapatalk
 
I don't think my radio has DAB. I only see options for FM MW LW and SW.
There's the multi CD player with memory card input and two cables in the glove box.
One media interface and one USB.

I do recall the unit displaying something like "no device available". I'll take a picture next time.
 
I don't think my radio has DAB. I only see options for FM MW LW and SW.
There's the multi CD player with memory card input and two cables in the glove box.
One media interface and one USB.

I do recall the unit displaying something like "no device available". I'll take a picture next time.
Even if you dont have a DAB, it could simply be the Radio Module because of the aerial being behind the rear windshield which usually looks like it has a lot of humidity during winter/rainy days. OR one of the other audio components. Waiting for this to arrive so that I can go through a process of elimination on my loss of sound although now I am confident is the damn DAB MALE&FEMALE MOST Fiber Optic Loop Cable Connector For Audi BMW Mercedes Porsche | eBay
 
I did notice a lot of condensation on the back window last week.
 
I did notice a lot of condensation on the back window last week.
Keep an eye before the dealership makes you spend tons of money :D
 
A few months ago the radio would occasionally cut out, no sound. The screen showed the channels as usual but no sound. Switching to CD and back to radio restored the sound. Now it's worse. Radio sounds briefly on startup then cuts out.

Could you clarify, did you lose CD audio too or is it only radio that cuts out?
 
It varies. Usually the CD will produce sound, and the radio wont.
But I think there's been occasions when both were silent.
The latest behaviour is the radio sounding for half a second after starting the car then going silent.
 
Radio was working this morning for 10 minutes. Stopped car/engine, restarted, no radio sound. And the CD was not showing the disc track.
 
I don't have to worry about the radio losing sound anymore. It's all gone. The screen is blank, apart from the bottom strip showing air con info. No radio, CD or navigation.
 
Since you are losing audio from the CD, I cannot see how the rear window antenna system could cause it. Must be either the MOST fibre ring itself or one of the MOST ring control units. Likely the audio tuner and amplifier unit at the trunk. I understand you have already checked it for water damage.

Diagnosis should help with details.
 
I haven't pulled boot liner yet. Was looking at it this morning, will do it at the weekend when I'm back home.
Found an interesting video showing a guy looking for fibre loop related problems by pulling devices and replacing with a simple loop.
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Removed the amplifier again. This time I took the can apart to inspect the circuit board.
There was the usual black gunk on the board near the fan. Cleaned that with contact cleaner, canned air and a hot air drier.
There was signs on corrosion on the shielding around the radio receiver, and I didn't think much about the
haphazard way blue lacquer had been unevenly applied to the bottom of the board.

When assembled I had sound, but like the first attempt had to start the fan spinning with a screwdriver.
All worked for 5 minutes, fan becoming nosier. Turned off engine, turned on, no sound!.

I've going to buy a new fan, it's nothing special: ICFAN 3010 3cm 12V 0.14A F3010EB-12UCV 2-wire notebook cooling fan | eBay
 
circuit board
 

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I've changed the cooling fan. Same fan, but the lead was shorter so had to cut the old lead to extend the new!
The old fan bearings were definitely shot, the new fan spins freely.
When assembled the sound came on and the fan span up without me having to nudge it.
However, the new fan bearings sound terrible, I wonder how long they'll last.
 
It worked for half an hour. On returning to the car in the car park, sound was off again.
I'll have to get this fixed as no sound stops the hands free call system and limits the navigation system too.
 
I was hoping this would improve in the warm weather, it hasn't.
But while there's no sound for the radio, it will play the mp3s.
There's a post on the internet somewhere that throws suspicion on the aerial components.
Rather than risk £300 on a second hand ebay amplifier I'm considering throwing £30 at a "Amplifier Antenna A2218207989" instead.
 

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