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No sound from speakers

8K views 1 reply 1 participant last post by  V12StealthHunter 
#1 ·
Some of you may already know that I'm in the process of restoring/reinstalling the original Becker unit into my car. I've just fit all the original Becker stuff I bought from someone parting a 560SEL on here, into my car and I've got no sound. Not even static.

I bought the car with some Sony unit which played only through the driver's side door (or dash?) speaker.

Not sure what its called but there is a 3 pin connector that goes into the pre-stage? of the Becker unit. When I pulled the Sony radio, I found that they had connected the powered outputs to this plug.

Could someone clarify a few assumptions here.

1) That little matchbox sized box at the back of the becker is the pre-amp right? The one with the 3 pin connector. The one with the little white "B" sticker on it in the photo below.
2) And that goes straight to the 2 amps behind the rear seat backrests?
3) All the speakers are powered by the component amplifiers? i.e. none of them are driven with the radio directly, even though there are two powered outputs at the back of the Becker? These powered outputs are left unused in the 10-speaker system cars.
4) Disconnecting that Becker Alarm module will not disable the audio system?

I've connected up everything to the Becker radio and it seems to turn on, tune and finds stations. But I hear nothing. Not even static. From any of the speakers. I did bench test the Becker (from its powered outputs) and it worked fine.

I tried another pair of amps and it made no difference. Anyone by chance have a pin-out diagram for the big connector that goes into the amps?

And near the main power connector, there is a little spade terminal. Its not connected in my photo below. What is that for? Is that the signal for the antenna? Does it go into a blue wire by any chance?



Here is a picture of the connections I found when removing the Sony unit.



Any help appreciated. Thanks.
 

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#2 ·
Yeah baby! Got myself the wiring diagram and figured it out! All works beautifully. All sounds amazing.

I pity the fool who thinks he can spend less than $5k on hardware and beat the Mercedes sound system.

Because each channel is driven by its own little amp, there is amazing stereo separation. After mid-1988 they even started installing active radio interference suppressors.

My problem was that I hadn't connected the power antenna. Which I found out is also used to signal on the amps. And all my assumptions above were correct too.

I've attached the wiring diagram I used for the rest of you.
 

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