Benjamin Altpeter

Decided to start posting about stuff I #repair. First one: A Volkswagen Beta V car stereo by Blaupunkt (almost as old as me!) that was working except for one small detail: no sound output

I don't know much about analog circuitry, so chasing the (lack of) audio signal backwards through the amplifier stages was a fun challenge. And the first use for the oscilloscope that's been on my shelf for ten years.

In the end, it only needed one wire: A via had broken!

Full notes: https://git.my-server.in/baltpeter/repairs/-/issues/16

Volkswagen Beta V (Blaupunkt 8 631 122 603) car stereo: No audio output (#16) · Issues · Benjamin Altpeter / repairs · GitLab

Model number: 8631122603 from a VW Lupo numbers printed on PCB, case, and stickers: VW BETA 0.906 000869, 0151A6-O, 0151A6-U, VWZ1Z2Y7100143, 8638300151, 8 635 132 772...

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Dec 20, 2024 at 10:08pmElk
Show threadBenjamin AltpeterDec 20, 2024

I especially enjoyed chasing information—after all the stereo is almost my age!

The main audio amp had a white-label part number, so I initially had no pinout—until I found a Romanian forum from 2007 explaining that it is just a TDA7376B.

And my favorite part: I even found an official schematic and board view provided by the manufacturer. Better yet: I'm allowed to distribute them, courtesy of Blaupunkt-Werke GmbH, Hildesheim! Grab a copy: https://git.my-server.in/baltpeter/repairs/-/issues/16#note_6106
How nice compared to today.

Volkswagen Beta V (Blaupunkt 8 631 122 603) car stereo: No audio output (#16) · Issues · Benjamin Altpeter / repairs · GitLab

Model number: 8631122603 from a VW Lupo numbers printed on PCB, case, and stickers: VW BETA 0.906 000869, 0151A6-O, 0151A6-U, VWZ1Z2Y7100143, 8638300151, 8 635 132 772...

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Show threadBenjamin AltpeterDec 20, 2024

And thanks to the schematic, it was also pretty easy to mod in an AUX input that replaces the cassette drive, making the stereo much more useful.

All it took was soldering in the three wires of an AUX cable into the cassette input of an audio mux and three bridges on the cassette connector to fool the unit into thinking a cassette is inserted.

Here are the instructions: https://git.my-server.in/baltpeter/repairs/-/issues/16#note_6123
I have since also successfully performed the same mod on a Volkswagen Alpha by Blaupunkt.

Volkswagen Beta V (Blaupunkt 8 631 122 603) car stereo: No audio output (#16) · Issues · Benjamin Altpeter / repairs · GitLab

Model number: 8631122603 from a VW Lupo numbers printed on PCB, case, and stickers: VW BETA 0.906 000869, 0151A6-O, 0151A6-U, VWZ1Z2Y7100143, 8638300151, 8 635 132 772...

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Show threadGabisPhotos 📷Dec 25, 2024
@baltpeter ... and we say THANK YOU 😉