On Wed, Mar 24, 2010 at 3:01 PM, Dave McGuire <mcguire at neurotica.com> wrote:
On Mar 22, 2010, at 5:07 PM, Brent Hilpert wrote:
I dealt with a reasonably complex async-design logic system from the 60's
in
reverse-engineering and repairing a Casio AL-1000 calculator:
?
http://www.cs.ubc.ca/~hilpert/eec/misc/CasioAL1000Tech/index.html
and in particular:
http://www.cs.ubc.ca/~hilpert/eec/misc/CasioAL1000Tech/electronics.html#edg…
What I call 'edge-pulse gates' - a sort of monostable - are injected into
the
logic at appropriate places to soak up the glitches (one would have to
look at
the schematic to see where/how they are actually used).
?Wow.
?I am impressed. ?That's one of the most detailed and well-presented
reverse-engineering projects I've ever seen.
Wow indeed!
That display looks familiar - I might have one on my shelf. I picked
up a PCB loaded with vertically-mounted Nixies plus a neon-bulb
"minus" indicator many, many years ago at Dayton. I have yet to
assemble a driver for it, but I've always thought about repurposing it
as a clock/calendar display.
The PCB has a small bundle of wires coming off one end, and the foil
pattern shows a multiplexed arrangement, IIRC (so 10 cathodes and
13-14 anodes, if I'm remembering it correctly).
I should check the PCB for any tell-tale markings.
Thanks for the link - it's certainly an interesting device.
-ethan