1977 450 SLC Radio install

[breastroker]

I just installed the eBay stereo that looks similar to the older Becker radios.
Chromed face plate, takes one CD and has a slot for a SD card, links with phones and has aux input.



My car came with the Becker Mexico according to the data plate.

Found something behind the glove box, is this the amp?





Also how can I track down the rear speaker wires. I installed Kenwood 4" KFC-1065R speakers in the front. A tight fit both easily installed. I put these in as they had a built in tweeter, and didn't require an amplifier.

I HATE PHOTOBUCKET

[ScooterABC]

your photo link is busted.

[breastroker]

I took out the small rectangular box, looks like the amp that goes with a Becker Mexico.
The PO sure made a mess of the Kenwood stereo install. He may have been a Doctor but was horrible as an electronics technician.

I have a LOT of Mercedes manuals but none show the radio stereo system.

Can someone send me a PDF or photo of the wiring for the 1977 Becker Mexico, radio to speakers?

I found the green-green black wires for the front right speaker, and part of the amp harness that I think goes to the consul fader switch.

What I need to find it the wiring colors and where they are routed (left or right side ff body)

I have spent hours doing the Google thing, nothing for the 1977 Becker GP or Europa II or Mexico.

[ScooterABC]

As I mentioned, your picture link is broken, at least for me.

I don't think Becker / Mercedes used color coded wires. Just green and black as I recall. Speaker wires go from the amp to the fader and from the fader to the speakers. The fader will actually have little Becker plugs on it where the input and output go. So there is really nothing to diagram.

The wiring between the Becker Mexico and the amplifier consists of one big grey cable that has a ground wire running with it. The cable plugs into the amp, the ground wire slides on a terminal on the amp right next to where the cable plugs in.

If you are unlucky, the person who removed the Becker Mexico cut the cable. Well, unless you have the Mexico it doesn't matter that they cut the cable. The amp has value, don't toss it.

Scott
and I hate photobucket too.

[breastroker]

Yes the previous owner screwed the install as bad as I have ever seen one.

Problem is he put a Kenwood amp under the drivers seat. So far I haven't found the wires going to the rear speakers.

The new front speakers seem to be perfect match for the stereo, do not need an amp driver. The rear speakers may need an additional amp, I have a newer Rockford Fosgate that would do the trick if needed.

Pretty sure the Becker amp is in good shape, like every thing on the car it still looks new. Car is up to 33,400 miles now, must have been kept in a climate controlled garage as the 1995 tires still looked like new, they had 4000 miles on them. All other rubber is in great shape. I would love to go to a Becker Gran Prix, no need for the Mexico cassette player.

[ScooterABC]

I think you are going to have to trace the wires back from the speakers.

I'm curious as to what you bought on ebay. You said it looks like a Becker but.....

Becker Grand Prix is a great radio. Sacrificing push buttons for a cassette deck on a Mexico just doesn't make sense anymore. Except lots of us are listening to streaming audio anyway and never touching the dial or buttons. A later stereo Grand Prix is one of the few Pinstripe radios that I don't have. I do have the much more coveted small-face Becker Grand Prix mono.... :-)

[breastroker]

Look at Classic Becker Mexico Europa Style AM FM Stereo Radio CD USB AUX DIN BLUETOOTH | eBay

[ScooterABC]

Oh.
Custom AutoSound USA-4 in Dash AM/FM/CD MP3

For a minute I thought you meant this:

Becker Mexico Retro - Car Navigation in Retro-Look

[Tomguy]

I agree with tracing the wires. You may even want to just run all new wires, if the previous ones are badly hacked/spliced, just so you're sure you have a good, clean circuit (speaker wire is cheap enough usually). I don't have any R107 or SLC experience, but does the car have a fader knob? In the 108s and 109s, there was a fader knob in the dash. The stereo output went to the fader which controlled front and rear - so there were only left and right speaker outs from the radio itself. Maybe the SLC is the same?

If that's the case, you have two options. One is to feed the LF + RF speaker circuit to the fader, or the other is to just bypass the fader with all new direct wiring.

[Idle]

To post what Tomguy said in a different way....

The original radio had a long gray wire coming out of the back of it. This was a plug that ran a group of wires back to the little box you found which is the amp.

The amp is grounded through the gray wire from the radio and also receives its' power through the same wire. Coming out of the amp will be a right and a left speaker wire, a positive and a ground for each side. In other words, four wires, two black and two green.

These then plug into a fader which is usually located in the console. This fades the speakers front to back. There is no side to side.

But as all of that is gone you are left with a clean slate.

Trace the wires back from the back speakers. Or look in the console area under the wood that holds the speaker fader. I would bet the rear speaker wires are still there as it would be the easiest place to connect them when the aftermarket radio was installed.

And don't toss that amp or the bracket. They are interchangeable with any Becker using an amp and they usually sell on Ebay for around $65. They are purchased by owners who wish to return their cars sound systems to original and now have to find not only the radio but also the amp. The bracket is the hardest to find because they are usually thrown away when a new stereo is installed.

[ScooterABC]

Originally Posted by Idle

And don't toss that amp or the bracket. They are interchangeable with any Becker using an amp and they usually sell on Ebay for around $65. They are purchased by owners who wish to return their cars sound systems to original and now have to find not only the radio but also the amp. The bracket is the hardest to find because they are usually thrown away when a new stereo is installed.

The brackets are easy to find if you go to junkyards - often the amp is removed from the car but the bracket remains. I've gotten a lot of brackets out of W116 sedans.

The stereo amp can be used with any Becker stereo radio until they went to the digital style. Can't use it with a Becker mono radio.

Speaking of returning things to original, at this point the one piece of the Becker system I would ditch would be that little amp. You can get a plug-and-play cable that goes from the big grey cable with plug coming out of the head unit and mating to wires setup to go to a "modern" amplifier. This greatly improves the choices you have in speakers since you can have an arbitrarily large amount of amplification. Our 1973 Alfa GTV has a Becker Europa Stereo mated to a 200 watt Panasonic (I think) amplifier. I didn't want more than 200 watts. It's difficult to find a new amplifier that small.

[breastroker]

Thank guys. I was able to get the speaker wires off the amp before removing it. It looks like the speaker wires from the amp goes to the center console fader switch. Every thing there was clipped off and so far I haven't been able to pull the wire cable out.

It looks like Becker used these same speaker plugs on many of their radios. I have later Becker Europa 599 with cassette that was a Becker "original replacement part" that I have had for over 15 years. With the speaker plugs I can test it out now.

[breastroker]

I found the wires to the rear speakers, on the right passenger door sill the smaller black plastic sheath over two pair of wires, black/back and green/black. I found the ends behind the stereo installed.

No does anyone else here have a SLC? The rear shelf speakers are bigger than 4 inch, looks like 5 inches across the top of the speakers.

I have several good new 4 inch speakers, but want to go larger to 5 or 5.25 inch rear speakers.

Any suggestions???

[breastroker]

I ended up with 5.25 inch Rockford Fosgate R1525 speakers. They fit PERFECTLY in the holes of the SLC rear shelf. And they sound great.

Only thing left is to get a Dremil 90 degree attachment as the old MB speakers were held with 3 screws and the Rockford with 4 screws.

Can you guys see the photos?

[breastroker]

Can others see these photos?