IMSAI woes

From: Seth J. Morabito <sethm_at_loomcom.com>
Date: Sat Apr 4 02:32:38 1998

Hi all,

Well, I've got some good news, and I've got some bad news.

The good news is that I've finally had my IMSAI 8080 sent out to me
from Connecticut! It's in my "workshop" (a.k.a. the Garage) right now.

The bad news is... my parents, god bless 'em -- They really didn't know
any better, and it's partially my fault for not getting it shipped out
to me sooner -- well, they had the poor thing stored, along with my BYTE
and Dr. Dobbs collection, in an outdoor shed. Although largely protected
from the elements, this poor sad little IMSAI has endured two New England
summers followed by two New England winters in a non-climate-controlled
room. Great.

The practical upshot of this is that it's not doing so well. I need
help :)

The power supply seems to be worst off of everything. The boards,
although needing to be cleaned of some spots of mildew, seem mostly OK.
Possibly a few tiny rust spots -- I'd say 100% of the chips are replacable
by easily-found parts, either period pieces or newer pieces. But probably
99% of the chips won't need replacing. They seem to be doing very well.
I have two Cromemco ZPU boards, so even if one has some bad parts,
I should be able to take spares from the other.

But that power supply... eek. The transformer is covered in a thick layer
of rust, and the whole thing just looks dirty and mildewed. I think
the best course of action now would be to desolder every component of
the power supply and build a new one -- sadly, losing a bit of IMSAI
authenticity in the process. Oh well... Say, does anyone know where
I can get a pair of 95000uF 15VDC electrolytic capacitors? =) Oh, and
a pair of 10000uF 25VDC -- mustn't forget those.

The good news here is that I have the original IMSAI User Manual --
the one with complete system diagrams and assembly instructions, since
this was a kit. Full parts list and photos from many angles. This will
make rebuilding the power supply _so_ much easier.

The S100 backplane is mildewed as well. How should I clean this? I know
this is probably a FAQ question, but I still can't find the archives of
this list, I'm afraid.

I'll probably also need to replace the little screws that hold on the
front panel plexiglass. It's really odd how some little components,
like these, rusted over terribly, while 95% of the rest of the system
just has mildew or mold spots, and no rust. Weird (but wow I'm glad.
Of course, I think the chassis is aluminum, so it's no wonder it didn't
rust =) Time for a Fry's run...

If anyone would like to help me out with this little project, please
drop me a line. I'm a bit out of my league here -- see, I'm mainly a
software guy, and my hardware building/fixing experience is very slim.
I can work a soldering iron alright, but that's about where my electronics
skill ends :) I have, however, always wanted to learn.

Suggestions welcome! Note, however, that it is not productive to
point at me and go "HA ha!" :)

-Seth
Received on Sat Apr 04 1998 - 02:32:38 BST