R171 Poor radio reception

[slkalis]

I noticed that I may not be alone in suffering poor reception on the radio in the SLK R171.

Mine has been back to the dealer a couple of times because of loss of radio reception - typically, of all things, Radio 2 or 4 - as I drive down the M5 (say).

I explained that, when visiting Cornwall, I was lucky to get just ONE station, and that in places around Stratford-upon-Avon, where I live, the reception was very crackly/hissy. M-B replaced the entire aerial (base and antennae) but that did nothing, and they say that nothing shows up on STAR for the pre-amp.

What I want to find out is whether other owners of the 171 have had the problem - and ever managed to fix it!

Cheers, Phil

 

[television]

A fault in the cable or the amp 10, no reason to be that bad

 

[slkalis]

Thanks TV...interesting to see the schematic. But would STAR miss such a fault?

Cheers, Phil

 

[television]

One needs common sense on this fault and not STAR, the dealer only has to listen to the hiss on weak stations to know it is not right, STAR cannot pick up a antenna cable fault

 

[Frontstep]

Theres an unhealthy obsession with Star people thinks its the cure all for everything.

 

[slkalis]

Thanks again, TV and Frontstep. I tried to tell the dealer just what you both say: about the hiss. Yet they kept saying that STAR found nothing wrong - and they insisted on doing lengthy 'road-tests' in my car - in excess of 200 miles I later find!!!(taking the Michael, think!!) to see if they could find the symptoms (let alone the problem).

I told them that they should park the car next to another SLK and select 'Station List' and compare the two. I found that the one they loaned me showed more stations than mine in the same location. But they won't have it....

I am still pursuing the problem with M-B and will update the forum as it plays out.

Thanks again, Phil

 

[television]

The first move it to remove the radio and plug in another, no amp needed if only a standard short lead and see how the radio works, this shows if radio or antenna. A fairly common fault would be a transistor gone down in the front end of the radio, this again would cause poor sensitivity.

One has to start somewhere, and doing the above will give an answer.

The only reason we have amps in the system is because band 2 signals will not travel down 50Ω coax without an amp

 

[slkalis]

Remove radio?

Hi TV....you say: "...remove the radio and plug in another...". Is it THAT simple? I thought the radio was built in to the dash.
Cheers, Phil

 

[grober]

Its usually the aerial amplifier/spitter faulty or not getting power.

 

[television]

Hi TV....you say: "...remove the radio and plug in another...". Is it THAT simple? I thought the radio was built in to the dash.
Cheers, Phil

It is easy to take out and do that,,, one has to start at the core to see if radio or antenna. if the radio works fine with a separate antenna plugged in we then know the fault is on the car.

Another well know fault is where the inner wire on any coax plug breaks, this just leaves a capacitive coupling with poor weak reception.

There is no point in messing around with all the amps till we know that the radio up front is all good, we then work back. STAR could pick up a non working amp.

 

[slkalis]

FWIW: I had a look round the web for more info on SLK radios and found this most instructive video about how to remove the radio. I found it very interesting, and pretty much within my skill-level, assuming I could persuade my wife that it needed to be done, if for no other reason than I would be able to ensure all connectors were properly seated.

http://www.youtube.com/watch?v=m_gf0Lgi_HY

 

[slkalis]

Pre-amp failure

It's taken some time but, with a lot of nagging (I had a good teacher! ) I've finally got MB to accept that there is a problem with the radio reception in my SLK. The killer was when I explained that a drive down the M5/A30 into Cornwall meant that when I arrived in Cornwall I only had ONE (local) station to tune in to!

The process of problem determination went like this:

1. I explained that as the Audio 20 builds a list of 'receivable' stations for an area, two similar cars parked side-by-side should have the same list.
- so the SLK they lent me showed more stations on my driveway than my own. Hmmm.

2. I pointed out that if I get a given list of stations with the aerial connected, I should get a similar list with the aerial unscrewed and my finger touching the aerial connector (me acting as aerial!).
- with the aerial I got around 12 stations; with my finger on the aerial connection I got 14 - 16. The differences I had seen showed me that the radio or pre-amp was at fault as I was a better aerial than the car's - and they had already replaced the aerial.

3. MB ran tests (with STAR?) which showed (they said) that the amp was working electrically (?). So, they removed the amp from the aerial circuit and expected the number of stations to be reduced: it was not; it was the same! This indicated that the amp was at fault, ie: not doing anything.

MB have now agreed to replace the amp under warranty - in the next week or two. I look fwd to posting the results.

 

[television]

Thanks for posting with the good result

 

[slkalis]

Hi All! Well, MB have changed the pre-amp! According to their STARS readouts - where they showed me the before and after frequency sensitivity graphs for the system - there was between 10 and 20% improvement in signal capture. This was borne out with a drive through some of the known signal-loss areas around where I live.

So, all in all, a result. There are still hissy signal areas, but I think they are probably the same for any car radio. I shall have to accept that MB have done as much as they can for the me and the problem.

Now all I need is for them to fix the atrocious steering feel (on another thread).

Thanks to all who commented on this thread. Cheers, Phil Franklin.

 

[daibando]

radio reception

Ditto,mine is dreadful
Its a poor reflection on MB that they continue to deny this is an issue