Alan B. Pearce wrote:
> I don't recall a wand (I take it you mean like the digital pulse
> detector and injector probes), I only recall a bench multimeter sized
> instrument.

The one I saw was a wand with a pointy end like a scope probe when you slide
the clip part off.  The top of the wand was maybe 1 inch wide with a small
LCD display that showed the 4 digit HEX number.  There was another line
coming out with a clip on the end, a lot like a scope probe but longer.  If
I remember right, you had to clip that line to a clock signal and touch the
test point with the tip end.  There was a button on the wand to start the
signature.  Maybe this whole thing was connected to a bench instrument, and
maybe there were other connections.  I'm sure my memory is garbling a few
things from 29 years ago.

This was supposed to be the next great thing for production line trouble
shooting, but it never took off.  Part of the problem was you had to
stimulate the circuit to produce exactly the same digital signature with
respect to a clock and maybe a gate signal every time.  Too many digital
systems just don't work that way.  Even though this was at HP, I don't
remember us using this thing during production test either, certainly not
for the product I designed.


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000.
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist