Audio Project Amplifier Speaker Loudspeaker Kit
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Mercedes Becker Autoradio Trunk Amp - Click HERE for Original Thread
jf8620
Does anyone know anythin about this amp. It's becker Autoradio Amp in the trunk of a 1993 190E mercedes. It has some numbers 1901 1043.899/1100 and 11 G A BS 1043.821-373.

I just want to know how to get it to work. It only has a 12 pin plug. I can't seam to figure out what pin is the Remote. Or which pins are the input and output.

Ps it a very small amp with 2 tda7256 transistors and 2 MC33074Ap chips. There is a main fuse which i'm guessing is the 12 + and then 2 pins have direct paths to ground traces so im guessing there -12
jf8620
Here are some pics



Perry Babin
http://www.st.com/stonline/products...ure/ds/1473.pdf

Pins 9 and 11 are the speaker outputs of the IC. You should be able to trace those to the connector (~0 ohms between the IC and the terminals). It looks like they are the outer 2 pins on each side.

It likely has 4 inputs. They should go toward the op-amps. They should be easy to follow. If I had to guess, I'd say that the inputs were pins 4 and 5 from each end of the row of pins on the connector.

The one remaining should be turn on. Measure the voltage on it (B+ and ground connected) before connecting anything to it. If it's at or near ground, it likely requires 12v to switch it on. If it's at or near B+, it likely requires a ground to turn it on.

After you get the amp to power up, apply signal to each input (one at a time). If you followed the positives and negatives from the output IC to the connector, you can determine which inputs are positive and which are negative. If feeding any input pin produces signal on 'two' outputs, the inputs are not independant. If that's the case, it's likely that the positve inputs are both on top OR on bottom of the connector.

Of course, do this at your own risk.
audiobahnkid592
It appears the traces on the board have bubbled? Is this true or just the photo?
jf8620
Thank's Perry i'll have to look into everything you said and see if i can get it to turn on.

Audiobahn The traces are pretty good not bubbled just covered in a clear substanace.
jf8620
Thank's Perry I got it to work Turns out the Remote is (+)

Pins:
1&2, 11&12 - output
4&5, 9&8 - input
6- (+) 12volts
10- ground
7- remote (+)

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