IMSAI 8080 (our show so far...)

From: Bill Sudbrink <bill_at_chipware.com>
Date: Wed Jun 30 10:16:16 1999

> Also where did you get that one... The description of the hacked front
> pannel sounds familiar to two I've seen.

I'd rather not say :)

But on the hacks note...
Digging through the binders I got with it, I have found:

1) Front panel assembly instructions. The 16 pin cable
is installed on the correct side of the board (not on the
component side). However interpretation of pin one is
vague. I quote:

CP-A TO MPU-A INSTALLATION
30) Using the 16 conductor ribbon cable with 16 pin
    3M dual inline connectr, insert one end into the
    hole pattern U2 from the back side of the CP-A board
    so that it can be soldered from the front (component
    side) of the CP-A board. The cable should be mounted
    so that it extends upward from the top of the chassis
    when the board is mounted.

End quote. Which end of the cable you choose to solder
to the CP-A will changed the orientation of the red
(pin 1) stripe.

2) Not schematics, but drawings of the trace layouts,
front and back. This allows me to ID the panel as a
CPA REV.4. The actual label with the IMS Assoc. etc.
is on the component side, hidden under the metal bar
that supports the switches.

3) Modification instructions. This allows me to identify
two of the modifications: One is a DRAM mod, apparently
changing how S-100 pin 71 is interpreted. This mod is
given the number: ECN 77-0039. The other is a change to
the behavior of the one-shots (74123s) to prevent spurious
triggering while in RUN mode. This mod is given the number:
ECO 77-0098. There is a third modification to this panel
which involves the lower right 7400 when viewed from the
component side (labeled U25 in the drawing I have).

Thanks,
Bill
Received on Wed Jun 30 1999 - 10:16:16 BST