old(ish) computers for sale

From: Eric Smith <eric_at_brouhaha.com>
Date: Mon Dec 7 14:47:34 1998

> [shrapnel-emitting diode]
>
> What about the Heat Emitting IC?

Those are entirely too common, in my experience.

The most bizarre thing I've seen along these lines, however,
was the light-emitting EPROM.

One day I noticed that:

1) My Apple ][ was acting somewhat flaky.

2) The 80-column video card, a Videx Videoterm, was getting
    rather warmer than usual.

3) There was light coming from the video card.

I put the card on an extender, and determined that the
source of light was the firmware EPROM! There was an arc
between two of the bond wires. The EPROM was a 2708 EPROM,
which you will recall used three power supplies, +5, +12,
and -5V.

Amazingly, the EPROM was still completely functional,
as the 80-column card was working fine. But it was
pulling the Apple's 12V supply down to about 8V, which
was causing other things to flake out.

I replaced the EPROM, and unfortunately I didn't think to
save the arcing one.

Just at a guess, I'd imagine that the spectra of light
emitted by the arc probably included enough short-wave
UV that the EPROM would eventually have erased itself.
Received on Mon Dec 07 1998 - 14:47:34 GMT