This is awesome stuff Jon. There is a fellow on my motorycle list, the
XS1100 Yamaha list, and he reverse engineered the CDI ignition box, the
regulator and the rectifier for our bikes. He then went on to reverse
engineer most Jap bike regs and rectifiers and now has a business supplying
them to us older bike crowd!! He puts them in his own box, and rewires the
harness connectors so they are factory plug in. He has even sourced the
oddball connectors in Japan and can supply new ones for those. Some are
unobtainable however. I'm sure what you are doing will be a HUGE service to
the vanagon crowd. Do any of these parts and pieces fit my 77 Bay Westy??
Regards,
Courtney

----- Original Message -----
From: "jon" <jon@KENNEKE.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Sunday, January 07, 2007 1:30 PM
Subject: Idle Stabilizer Control Unit Reverse Engineering

>I recently received an ISV control unit (1986 and later) for disassembly
> (among other things). Thank you Mike!!! This research confirms several
> hunches that I had.
>
> The control unit consists of 16 op-amps (4 LM2902 quad chips), a 4 Amp PNP
> power transistor for driving the idle stabilizer valve. I would bet
> that this transistor is what fails when a control unit goes bad. This
> part, a BD438, is readily available. So, I think repair would be possible
> in most cases.
>
> My other bet is that if an IS valve shorts, it will blow the transistor.
>
> How many folks out there have a *bad* IS control unit? I'd love one to
> verify if it's the transistor that went south.
>
> The unit is much easier to open the a 1.9L IS control unit (which
> requires cutting). There are 6 clips molded into the case. Pry these away
> from the connector bulkhead, and pull the whole thing out of the case.
>
> Pics of the unit are here:
>
> http://www.kenneke.com/vwfi
>
> I am going to be having some exciting news about all this FI stuff soon.
> Stay tuned!
>
> Jon