Today’s teardown subject is another vintage find: a 1974 Casio Personal-Mini.
Still in the original box
$19.95 from a formerly well-known department store
Oddly enough the packaging foam is still good
It’s alive
Hmm, I bet it’s been more than 20 days since purchase
They got it right about growing number of Casio owners
0.18Watts? You can fly to the moon on less!
2 AAs is nice, though they kinda had to go that way due to power consumption
Interesting board to board interface with soldered pins. Probably good for a couple bends.
TDK CD-14202- is that a Boost converter for the display? It’s gotta be since I see no inductors/power transistors on the board.
Going around the converter pins with a scope, I see a few voltage rails, interestingly enough all negative relative to the battery negative terminal: -6.5V, -18V, -23.5V
NEC uPD178C
Along the same line, notice color coding of the battery wires: Red is Negative, White is Positive:
And some more closeups of the VFD:
Slow thinking video
To illustrate how this thing behaves, I made a short video. Let’s just say it takes its time thinking
User manual
And here are some shots of the user manual:
Cover
Pages 2-3
Pages 4-5
Pages 6-7
Pages 8-9
Pages 10-11
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Divide/equals makes the display roll IIRC,
/= makes it count, i dont know why. You have to hold the shift / arrow (?) key to see it counting.