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      Commodore Calculator, (sdf.org), 08/16/2018
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It was a good day for odd hardware yesterday! I drove over 
to St. Louis to pick the wife up from the airport, and 
decided to stop at a few thrift stores while I was out. I'm 
happy to report that the thrift shops over that way are far 
more interesting than the ones here in mid-Missouri. I 
grabbed a used LCD monitor and a few board games. I was 
happy enough, but then at the last moment I noticed an old 
desk calculator, a Commodore US*1M!

For $3, I bought it. I'm not a collector, but I couldn't 
pass it up. It was made in 1972 by Commodore, at the height 
of their calculator days and pre-computer days, I believe. I 
took it home and plugged it in, and it worked great (for 
being 46 years old- there's a little flicker in the display, 
and the negative sign doesn't always show, but it works!) I 
used it to tally up my receipts for the budget.

I'll try to put a picture here on gopher at some point, but 
to me the thing is beautiful. It's in exceptional condition. 
It's a clunky old thing, but it's a piece of computing 
history, and I really enjoy it. I plan on having it on my 
"retro desk" at some point...

Which brings me to another thing that happened yesterday: I 
got my z80 sio/2 chip from Mouser in the mail, 3 days early. 
I promptly plugged it into my Grant Searle CP/M design, but 
I haven't powered it on yet. This is the design that I built 
3 times on breadboard with no success, and then built on pcb 
with no success. I *think* that my problem is the cheap ebay 
sio/2 chips that I bought. I'm guessing they're fakes. I've 
swapped out the other ICs with known working ones, the sio/2 
was the only one I didn't have reliable sourced spares for.

When all is said and done, I want to have a desk with my 
proto board z80 plus cassette interface, my pcb z80 with 
CP/M and CF storage (if I can get it working), and a few 
other fun things. I'd love to manage a nice 80's CRT of some 
kind, but I don't ever see them around any more. We'll see, 
eventually, what I can pull together. The calculator will 
definitely be there next to everything else.

(if you want to see my z80 stuff, with pictures, it's over 
on my grex gopher hole under projects...)