On 8 Mar 2004 04:26:00 -0800, (Paul Probus)
wrote:

Thank you for your response Wayne. I heard from a Rich D. who emailed
me directly. I had not realized that this was a reverse engineering
project. I thought it was a controller that was hashed out based
around the TDA1085C. As far as the labelling, perhaps it is one the
original DXF file, which the AutoCAD that I have at work cannot open,
but I opened the GIF and the PDF files and R2 and R4 as well as many
other components do not have values (none of the diodes and neither of
the transistors, for example), at least none that I can pick out.

Ok I just checked and your right. It must of been a earlier version
which got posted to the dropbox. I was short on time when the request
for posting to the dropbox was made and didn't have time. Thus I
believe it was Don Foreman who actually did it. Before that I'd just
emailed it to a few people.

I just did this since surplus places where selling these controllers
with surplus treadmill motors at that time. Many people where wanting
to get rid of some of the features (primarily the return to zero speed
before restarting) but nobody had a schematic for it. Thus I reverse
engineered this schematic so that the real electronics guru's could
figure out how to modify it. I'm more in your category in that I can
read a schematic and figure a few things out but starting from scratch
is way beyond me.

My hope was to be able to use another kind of feedback vs. the
tachometer, such as back EMF sensing or perhaps a hall sensor to sense
current, however, not being very electronically inclined, I don't know
if those ideas would work.

To my knowledge they won't work with this chip.


Wayne Cook
Shamrock, TX
http://members.dslextreme.com/users/waynecook