Date:         Sun, 21 Feb 2010 19:31:28 -0800
Reply-To:     John Bange <jbange@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         John Bange <jbange@GMAIL.COM>
Subject:      Re: ISC troubleshooting
In-Reply-To:  <de48c0be1002211128u5c948b6dv3f0942da4e380435@mail.gmail.com>
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>  Someone, I think
> John Bange, started to map the circuitry but it seems to be a project that
> died. I have taken the defective unit apart and seems almost comical in its
> design and construction - so many resistors, transistors and capacitor!
> None
> of them appear damaged to my eye so I'm wondering what has failed.
>

Yeah, I got about 10% done with that before I realized that That Way Lies
Madness. It is almost comical in its design. It's a fantastic bit of
hand-tuned analog circuitry, a throwback to a simpler age. It's almost
steampunk in its fabulous complexity. I'm not sure why VDO went analog with
it. Perhaps digital microcontrollers were still just s little bit too
expensive.

I'm still working on a digital replacement. The controller and interface are
pretty simple--- just a few transistors and resistors with an Atmel chip.
I've already built a couple test units, and they actually worked. The hard
part for me is making something that doesn't fall apart. Automotive
applications just aren't very tolerant of my sloppy soldering style.

--
John Bange