> What, just to grab a working unit (if you have one...seems like you're
> stuck like me, and that's why you started the whole project in the first
> place...:-) and connect it to a 12VDC power supply and put a test
> lamp?...:-)

That is the problem: a working unit. The one I have (the pictured one) is
kaput.

> And you can't be sure the 555 will create the right signal for this analog
> computer (the hall sender doesn't crate square waves).

True. But, a 555 can be "configured" to output saw, sine, etc. waves. One
thing I can do quickly is put a 'scope on the hall and post that pic.

Our only gas Vanagon is my wife's 86, and she gets nervous when I am
digging around with meters and stuff on her car. I've got some large
maintenance project planned on her van in November, so that is a good
time to play with her ISCU. ;)

> Nah, that's OK, I can handle that...I simply don't want to introduce
> another variable into the debug session.
> BTW, I got me a few BD438's and will try them once I know what to expect.
> BTW, did you see the pictures I posted? Do you still want me to send them
> to you too?

I didn't see the pics. Send them on to me, and I'll include them on the
site.

Jon