300SD Radio Change

[jollybits]

So I gave up waiting for my friend who offered to help install a new radio in my 300SD. This last weekend when I got together with my dad to change the oil on our respective Mercedes, he gave me a hand with some of the electrical bits that I wasn't 100% confident of. I was happily able to preserve the dash grills, but the rear shelf speaker grills had a 3-screw setup that would not work with the new speakers. I think the overall look is very clean and I'm happy with the sound quality. Here are a few pictures of the end result.


Rear speaker with new grill. The speakers are Blaupunkt Blue Magic TL 130.


Front speaker grills are intact. Underneath are Blaupunkt Blue Magic CL100. These new speakers are 4" circular instead of the original 4"x6" oval ones. The driver magnet was a bit large and nearly didn't fit above the vent duct below. A little bit of trimming on the forward side of the speaker hole solved that for me.


The new head unit. A Blaupunkt Helsinki 220 BT.

The old unit had ground and switched power (tied to the ignition). The new unit required ground, switched power, continuous power, and illumination (interior light dimmer). I didn't care much about the dimming, so I spliced the illumination and switched power together (whenever the car is on, the stereo is full brightness). For continuous power I routed a wire to the hazard switch on the center panel. I carefully shaved the shielding off of the red wire that goes to that switch with a utility knife, twined and soldered my new wire on, and wrapped the whole deal in electrical tape.

For wiring to the new speakers I was able to use the existing wires. I did however eliminate the fader. The fader wiring confused me at first but I was able to work it out. Each speaker has a + and - going to it, so I assumed the fader would have 12 leads (2 for each speaker, 4 for L/R input). In reality the fader only has 6. The ground (-) for each circuit does not pass through the fader. So you have + for L/R input, and + for each of the 4 speakers. The front and rear channels then share a ground right there (front left and rear left have the same ground, front right and rear right have the same ground). I cut each of these and simply ran wires to extend the pairs that went to each speaker.

If anyone is interested in the old radio (I remember a few people asking about it) here are some pictures:


Amplifier from under the glove compartment.


Other side of the amplifier, with link cable.


Front of the radio. FM and AM both work, but tapes will not play.


Back of the radio.


Unfortunately we cut this link cable before realizing that it could have been removed without cutting. There is plenty of cable on each side of the cut, so repair shouldn't be difficult.

[saw116]

Very Smart

Pity I am so far , I would have loved to take the mexico over from you

Chz all