IMSAI Score update/Spare BYTEs/Got an Altair too

Dave Dunfield dave04a at
Thu Jun 2 11:16:54 CDT 2005

>>If I recall correctly, the "logo" is composed of two parts, one is a
>>clear plastic sheet with black printing that gives the shape of all
>>of the letters, switch and light legends, etc.  Behind that, there
>>should be a sheet of foil backed white paper.  Those two sheets are
>>sandwiched between a sheet of clear and red Plexiglas.  Sounds like
>>you are missing the white sheet.

>I'll have to separate that part of the panel. What is the "white sheet" made
>of? Would glossy white card stock work? Maybe it slipped down out of view of
>the mask.

There are four "layers" to the IMSAI panel.

At the very front is a layer of clear plexiglass - for protection, and the
outer layer of the "sandwich".

Behind that is a thin layer of mylar, which is entirely coated in black,
except for the panel lettering which is clear (ie: "reverse video"), and
clear rectangles where the LED's show through.

Behind that is a piece of material which is white on the front, and foil
coated on the back. In the rectangles where the LEDs show through, there
is nothing.

The rearmost layer is a sheet of red plexiglass.

The LEDs show through the red plexiglas, though the holes in the white/foil
piece, though the clear rectangles in the mylar and through the clear front
piece - the red plexiglas in the read give them a nice obscured/deep-red

The panel lettering is the white side of the white/foil piece which is visible
through the clear lettering in the mylar, and the clear front panel. This piece
would not "Drop" or shift because it has 8 screw holes through it and is held
in place by the other pieces and the screws, and also because if it could, it
would hit the panel switches.

It would not make sense (although possible) to remove the white/foil piece,
since this would render ALL front panel lettering invisible, and would also
allow the LEDs to be visible at angles when they should not (when looking
through the lettering for example).

I think it more likely that the white part behind the IMSAI 8080 has been
removed or covered. It may be as simple as removing a piece of black paper
from behind the IMSAI 8080 logo - If necessary, you may have to cut a
piece of white paper to fit in this space. The worse case scenario would
be if the former owner used a black marker to color the IMSAI 8080 clear
letters from the rear of the panel... This might also be repairable, but
be very careful not to remove the intentionally black parts.

dave04a (at)    Dave Dunfield
dunfield (dot)  Firmware development services & tools:
com             Collector of vintage computing equipment:

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