Reinstalling a Becker Mexico cassette in a 1979 450SE

One of my friends in the Mercedes Club recently bought a nice original Mercedes-Benz 450SE. Is a 1979 model in Silver-Green metallic with date leather. It is equipped with a sunroof, which is surprisingly rare on an Australian delivered 450SE. The cars came well equipped with standard leather seats, self-leveling rear suspension, AC, power windows etc. The two features that they surprisingly didn’t have for such an expensive car is the sunroof and rear headrests. Both could be optioned. This car has the colour matched hubcaps that I prefer to the wheels. I was able to drive this car at a recent MBCNSW Night drive.

The car was quite original except for the broken 90s cassette player. Being a 1979 model, it would have come with a Becker Mexico cassette with a black front panel and the large knobs. The S-Class and the 280CE all got the Mexico, whereas the lower specification models had to settle for the Europa cassette. The big difference is the Mexico cassette has an external amplifier and the ‘wunderbar’ auto tune feature.

A wrecker in Bendigo had one of these radios, which was promptly purchased. Even though the Beckers with the black front panel are not as desirable as the pinstripe models, they are actually harder to find. They were only fitted to cars for a couple of years in Australia.

Our task for the evening was to test and install the radio. I already had a test rig set up from my Becker radio testing. These radios are very simple to set up. There is a switched power feed, ground and left/right speakers. There is also a cable between the remote amplifier and the radio.

We were quickly able to establish that the radio worked! It was able to tune FM correctly, volume, treble/bass all working correctly. The stereo light would come on when a station is strong, as it is supposed to. Surprisingly, all the bulbs worked. On the downside, the ‘wunderbar’ auto tune feature was no longer working, we could not test the cassette function as I don’t own one, the actual stereo decal in front of the bulb was missing, and we couldn’t test AM as it never seems to work inside the warehouse.

That was enough to install the radio in the car for now. The ‘wunderbar’ is a nice to have feature, so it could be repaired at another time.

Next step was to have a look at the car, to see how badly the previous installer had hacked up the wiring. I was also wondering if the original amplifier was still there. A lot of times, installers would just cut the wire and leave the old amplifier in place.

Turns out the bracket for the amplifier on the passengers side of the car was still there, but all traces of it and its wiring were gone. The installer had been rather lazy and just wired the 90s radio into the original speaker wiring. They had even left the fader in place. Both left channels were spliced into the left channel for the car, and same with the right. It was all held to together with electrical tape, so it was pretty simple to entirely remove the old radio wiring. I then used an AA battery to check if I could get sound out of each channel. I got static from both front speakers, and the left rear. Its possible a connection has come undone at the back for the right rear. Fader still worked.

I had some proper Becker connectors from my parts car, so I was able to re-attach Becker connectors to these original speaker wires. A quick test before putting it in the car was that the sound was pretty good. Even with the power antenna down, FM reception was decent.

On install, the speaker wires were not quite long enough to allow the amplifier to go back in its bracket. That could be a future improvement to add some more speaker wire. By this time it was almost 11pm. For now the amplifier was able to slot in under the glovebox and out of site. I also couldn’t see a trigger wire for the antenna in the back. Another improvement would be to trace where that is and see if the power antenna is still working.

With only a couple of hours work, the car now has a working Becker Mexico Cassette, similar to the one that it left the factory with.