bill_at_chipware.com

From: Richard Erlacher <edick_at_idcomm.com>
Date: Sat Aug 21 21:15:53 1999

Someone asked me for help with his IMSAI box, including the front panel with
which you've recently done battle. Do you have a schematic available in
some machine-readable form? I'd like to help this guy but it's a bootstrap
situation. Until at least one or two things are functioning, you're working
blind.

If you could send or point me to a machine-readable schematic of this FP,
I'd be better able to encourage this fellow. I'd rather not foist him off
on you.

regards,

Dick

-----Original Message-----
From: Bill Sudbrink <bill_at_chipware.com>
To: Discussion re-collecting of classic computers
<classiccmp_at_u.washington.edu>
Date: Friday, July 16, 1999 4:05 PM
Subject: IT'S ALIVE! (IMSAI)


>I meant to post this Tuesday, but things got busy.
>My IMSAI is up with the front panel, CPU and
>memory card. I can now reliably do all front
>panel operations and can toggle in and run short
>programs on either the 8K SRAM or 64K DRAM card
>(only one in the box at a time). For those keeping
>score:
>
>Replaced all chips on the front panel. All are
>now socketed.
>
>Replaced two switches on the front panel.
>
>Routed several traces around burned or otherwise
>damaged spots on the front panel.
>
>And... (this is the kicker)
>Re-patched the MWRITE circuit. The original (and
>incorrect) patch brought the SOUT signal to U25
>pin 5. What was actually required at U25 pin 5
>was NOT-SOUT.
>
>So next, I suppose, is to get the MIO working
>(at least the serial port) so I can get a terminal
>on this baby. If anybody has MIO REV.2 schematics,
>it might make my life easier. To begin with, all the
>chips on this card are socketed. It is a very neatly
>and carefully done soldering job. The following chips
>are missing: U8, U11, U30 and U34. I can see the
>silkscreens for U30 (74LS32) and U34 (8T20), but the
>sockets hide the silkscreens for U8 and U11. Does the
>absence of these chips simply indicate that one of the
>functions of this board is disabled?
>
>Thanks,
>Bill Sudbrink
Received on Sat Aug 21 1999 - 21:15:53 BST