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re: <E28> No Tunes When Braking

[email protected] (Jonathan)
Writes in Digest 261 
(Fri, 20 Sep 96)
Subject: <E28> Aftermarket Stereo Wiring (No Tunes When Braking)

>This is a followup to my earlier posting, where I related a >problem 
>with a newly installed aftermarket Blaupunkt >casette/receiver in my
>'87 535is. Several other digester's responded that their 535's >also 
>lost switched power when the brake lights are actuated.

A number of years ago I was involved with the development and marketing of
car audio at Denon. We experienced a problem with the Denon units at the time
with exactly this problem in BMWs of comparable vintage (c. 84-87). Our
findings were that briefly (under braking) there would be a voltage drop that
could momentarily (and I mean momentarily!) drop as low as 8 volts. We never
tried to determine why the voltage drop occured, figuring that the fact that
it occured was enough reason to make the product compatible. The voltage drop
certainly was not going to be corrected by BMW on existing product, and
suggesting alternative methods of connection would be largely ignored by
installers, so...


The Denon units had an internal protection circuit, that would sense this
drop in voltage as a potential cause of damage to the electronics or cause
the CD player or cassette mechanism to skip or jam tape and would shut down.
The cut off voltage as I remember was set at about 9.0 volts. The engineers
either lowered the threshold or changed it to look for a longer reduction in
voltage (I really don't remember which it was) in any case this cured the
problem with no apparent ill effects to the head unit.

I would suspect that the Blaupunkt units may have a similar circuit that is
not happy with the voltage drop. My suggestion would be to contact Blaupunkt
and ask them what's the deal. 

Blaupunkt Division  of Robert Bosch
2800 S. 25th ave. Broadview IL. 60153
708-865-5200
fax 708-450-8554
This info dates back to 1995 so the area code is probably (847)
As of 1995 the manager of customer service is listed as Lois Barton, Jim
Frazer is manager of engineering.

BTW my E28 came with a Panasonic CD radio, which works just fine. The rest of
the system is for the next week or so, original, what dreck the speakers
are... just awful.

OK, now I promise to go back to lurking.
regards,
Ken 
[email protected]

85 528e
78 Alfa Romeo Spider Veloce 

e.media  - Marketing and Consulting
Specializing in the Consumer Electronics Industry