5 Mar
2002
5 Mar
'02
12:32 p.m.
On Wed, 6 Mar 2002, Tony Duell wrote:
Good point...I added it to the subject already. :)
If you're asking about a 'generic' module
(drive, PSU, etc) that may
well have been used in other machines, then post any identification
that's on that module.
I forgot to get the version off the board last night, and unfortunately I
left it the lab today, so I'll have to get it later. Anyway, it does have
a socketed 40-pin ASIC on it right in the center. The only standard
devices I noticed where some 74xx ones, and an LM339 quad comparator. I
didn't notice any transistors, and I was sort of wondering how the stepper
was driven. I would think that if whatever is driving it is blown, then
it wouldn't move at all.
I had considered swapping the socketed 40-pin IC between the working and
non-working unit, but I don't have proper IC extraction tools, and if its
got really flimsy pins on it, I might screw up my only working unit.
I have schematics for 4 versions of the logic
board...
The later ones have a 40 pin ASIC on them. The first worry is that the
stepper control circuit is mostly inside this ASIC, but the actual motor
drivers aren't (they're sections of a ULN2047 chip). The older versions
of the board have the stepper motor circuit built from TTL (which you can
still get) with discrete power transistors for the motor drivers.
Let me know which version board (or at least if theres a 40 pin chip on
it, or if there are 3 TO66-can power transistors near one edge) and I
will see what I can do to help you debug it.
-tony