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Premium Member
1990 SEC
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4,247 Posts
Discussion Starter #1
Something strange happened to my Original Equipment Becker radio yesterday; it suddenly lost AM radio.

Strangest thing. FM radio and the tape works just fine, but AM radio is suddenly very low in volume (cranking it up all the way to hear anything) and can't get stations.

Every once in a while it seems to work alright, but then it fades out again. Like I said, FM and tape works just fine.

Any ideas?

Is there a separate antenna connection for AM?
 

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1988 300 SEL
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6 Posts
Interesting - my '88 also has that same problem. I just got it a couple weeks ago so I have no idea on the history (when it happened etc).

As you said, everything else works fine.
 

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1991 500SEC 55K mi. 1987 560SEC Now 153K mi. 2020
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Hey there, AxelWulff,

Have you, no... I'd try removing the radio head, then cleaning the antenna plug > radio antenna socket connection. See how it is afterwards.

If the AM section is COMPLETELY gone, I'd send it to Becker in NJ for a 'refreshment'. Others will probably recommend an aftermarket solution, - not this kid.

Becker in NJ can assist, should you choose that route.

Cheers, MBL
 

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1990 SEC
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Discussion Starter #4
Not quite sure if I solved the riddle, but while I was going over the wiring of my radio this weekend to check for loose connectors, kinked and bent wires and other sources for bad connections, I checked the grounding of the antenna coax cable back in the trunk by the power antenna.

Well, the coax cable was very brittle and the ground wiring basically disintegrated in my hand.

Now the AM radio is almost completely dead. Only in areas where the signal is really strong do I have any kind of reception. However, the FM radio is still as good as ever. Totally unaffected by the lack of grounding of the antenna cable.

From what I have read, Becker is about the only radio company that grounds the antenna cable and from my experience it appears to affect only the AM band.

Oh well, how much is a replacement antenna cable?

I guess I could use a standard coax cable and try and to the grounding myself.
 

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1990 SEC
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Discussion Starter #6
Naomilla,

Yes, I had the classic trunk leak and redid the lower rear window frame over Christmas. So the cable may have corroded from water exposure.

It was not the clip itself that was bad, it actually looked rather good and shiny. It was when I removed the grounding screw and opened the clip that I discovered that the lead from the clip to the outer shield on the coax cable was bad and the mesh itself was quite corroded.

A new cable looks necessary to restore AM radio reception and new OEM coax cable is probably more than a new radio. Any bets on the price?
 

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573 Posts
personal experience....it costs too much money to repair Becker's. and its almost a guarantee that they will go bad again. All things have a lifespan, and one should respect that, and put them out to pasture.

i spend over $600 on repairing my Becker, only to have the problem resurface within a month.

My suggestion is to just get a new stereo. You'll be happier and richer for it.
 

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1991 500SEC 55K mi. 1987 560SEC Now 153K mi. 2020
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Hi Axel,

A replacement coax cable from (horrors!) Radio Shack is $7 for a 17 footer. That said, I've not looked at the MB connection, or grounding you speak of, but I take it there's a GND pigtail right by the antenna that's rotted.
There's gotta be a way either re-ground the existing coax or fit a ground to an aftermarket replacement. How about consulting a high-end car audio installer in the Philly area? I'm not suggesting CompUSA, or something like that.... An idea anyway.

BTW: For sure you're correct in saying that is the cause of lack of AM. It is not the Becker that is faulty here, AM just works differently than FM. For instance - you can to listen to FM while driving through a short tunnel & with AM..... you loose the signal almost immediately.

Regards, MBL
 

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1990 SEC
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4,247 Posts
Discussion Starter #10
MBL,

Great schematic, but no, that is not how it was connected.

On your drawing the grounding wire is connected directly from to the antenna.

The grounding wire that I had looked like a normal cable clip, sitting on the coax cable about 12" from where it is connected to the antenna.
It was only upon opening it that I was sure it was the grounding for the coax cable.

Time to bring out the old soldering iron.
 

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1991 500SEC 55K mi. 1987 560SEC Now 153K mi. 2020
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Hi Axel,

I just got a clearer picture (I think). I found a photo of a replacement antenna which has a little grounding wire (like the posted diagram) and what wasn't clear to me is that the antenna lead appears to be screwed onto the antenna. This lead has a female COAX (like you said earlier) end at the antenna & terminates in a regular 'radio antenna' (male) end > which is plugged into the long cable routed forwards under the back seat.......

The clip you refer to, sounds like a standard metal d clip that encircles some bare outer sheathing (on this lead) & is screwed to the body, to both provide ground & locate the cable, yes?

Providing the above theory is correct, I think it would be pretty easy to repair your corroded lead cable by cutting out the corroded part & grafting in some new coax to regain the length needed. [:D]

My prior reference to Radio-Shucks doesn't apply (obviously), but now............ You probably have some TV coax cables squirreled away in the closet? Check these pictures of my saved TV coax!

Let me know if you think it'll apply to your situation.

Cheers, MBL
 

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1991 500SEC 55K mi. 1987 560SEC Now 153K mi. 2020
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Axel,

I'm wondering if the std. TV coax will connect to the MB antenna (a long shot)? If so, it would take only 1 splice to accomplish, rather than 2. That would be nice.

Cheers MBL
 

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1991 500SEC 55K mi. 1987 560SEC Now 153K mi. 2020
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Axel,

With my reference above: "a standard metal d clip that encircles" I meant an adele clamp.

Moi, MBL
 

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1990 SEC
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Discussion Starter #14
MBL87560SEC - 4/11/2005 5:03 PM

The clip you refer to, sounds like a standard metal d clip that encircles some bare outer sheathing (on this lead) & is screwed to the body, to both provide ground & locate the cable, yes?
MBL,

You are quite right. The grounding of the coax cable is separate from the grounding of the antenna.
The grounding of the cable is just as you described; a D-clip with a lead to the outer shield wire mesh of the coax cable.

The standard TV coax (RG6 ?) is quite a lot thicker and stiffer than the Becker OEM cable, but because I only need to replace the couple of feet that is in the trunk that should not be a problem.

I do need to verify that the couplings are compatible (new cable to antenna, new cable to old cable). If that is OK I should be all set for a little soldering homework.[:)]
 
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