Tech Tip: Becker replacement wiring shortcut - PeachParts Mercedes-Benz Forum

csnow · #1 04-07-2003, 01:26 PM

My 1986 300E was still sporting the original Becker tape deck.
It actually stopped working entirely a year ago, but I just got around to replacing it.

I was not able to locate any sort of custom wiring adaptor harness for these models. Crutchfield had some adaptors for the speakers, but they were $13 + shipping, and I was still going to have to solder them onto the new unit.

This was my shortcut:

I opened up the old Becker, and cut out the male power connector plug and the speaker connector plugs from the back of the unit. I simply cut away whatever circuit board, wires, and plastic I did not need with diagonal cutters, and got down to just the connectors with bare pins on the backside.

I then soldered all of the wires on the new unit to the appropriate prongs on the old connectors. Heat shrink tubing and liquid electrical tape was used to wrap everything up tight.

The advantages:

1) All wiring layout and soldering was done inside the shop instead of inside the car. Easier to work at a bench, better lighting at night, and it is still freezing cold around here!

2) The factory connectors are really nice compared to the typical crimp-type that are commonly available.

3) No modifications to the factory wiring. No cutting, splicing, or hacking into harnesses. Plus, when my car is an antique, someone could easily slap in an original Becker for extra points at the Concourse d'Elegance. (Yeah, right!)

I stuck with the old speakers for now, so I just used one channel, and kept the factory fader. I had thought the front left might be out, but it was something with the Becker, because it works fine now.
Anyways, the speaker are now the weak link, but I am loving the MP3 capabilities of my new Sony CDX-MP40 ($159 net at pcrush.com).

Also, I wired it up to use the 'Accessory' circuit as the main power supply instead of the 'Battery'. One dead battery, and that standard German 'convenience' of having the stereo stay on when the ignition is off will not look so great anymore!

Best of luck with your project.

anthonyb · #2 04-20-2003, 12:38 AM

Out of curiosity, how'd you wire the power connector up? I decided to go the same route, ended up wiring bare wires to the little stubs that normally go into the pcb, didn't know if there was a better way. I'm a little bit concerned about those solder joints, but I figure I'll try to treat it gently and see how it goes.

-anthony

csnow · #3 04-21-2003, 12:43 PM

That is what I did as well.
A little small in terms of surface area, but not too bad, and plenty strong in the end.

I slid a length of heat shrink onto the new wires before soldering, then slid them down over the stubs to prevent shorts.

Also, a heat sink clip is probably a good idea to prevent the hot terminals from melting the connector.

anthonyb · #4 04-22-2003, 12:58 AM

Yeah, I put some heat shrink on the connections too. I actually didn't use the 12V constant or the ground pins, those were wired separately, so I'm not too concerned about excess heat. Also slid heat shrink over the unused pins almost as an afterthought - now I realize what a really bad idea it would've been to have a live 12V bouncing around behind the dash! If I have to pull that connector out again, I may try removing that pin from the connector, then stuffing the hole with some kind of sealant.

As an aside, I was pretty amazed that Crutchfield was the only place that carries wiring harnesses for these cars. I went to three different local big box retailers/install shops, and all of them said I basically had to hardwire the unit to the car.

-anthony

wjm · #5 05-08-2003, 05:13 PM

no need to cut up an old radio. You can get a harness from becker.

Willy

wjm · #6 05-10-2003, 01:15 PM

I may have spoken too soon. They sent me the wrong harness. I'll let you know if/when I get one in hand.

Willy

wjm · #7 05-12-2003, 10:31 AM

OK,

Talked to Becker this morning and they are sending me out a new harness. As soon as I get it, I will verify that it works. What is needed is the M-Class connector. If so, that tells me that the plug in the M-class is the same as the DIN-ISO used in the 94-97 mercedes, except the gender was changed. Will let you know.

Willy