[sdiy] math question - somewhat OT

[KA4HJH]

>I had an SR56, which was my first programmable experience. All 99 steps of
>it. :-)

If like me your parents couldn't afford a 58 or a 59 the 57 was a decent
compromise. It had enough memory to keep you busy for hours and all the
programming buttons were conveniently placed.

>The NiCads lasted till maybe 1980, then they turned furry and I threw them
>away to prevent further damage. I still have the machine, and I'm guessing
>if I fed it with the right kind of supply it might work. But then again
>it... might not.

To clarify what I said earlier, the TI nicad pack has a small switching
power supply in it that boosts the voltage. When the nicads puke (and they
probably all did a long time ago) that's the end of the whole thing.
Unfortunately I never worked up the nerve to crack the pack open until it
was too late. If I'd removed the batteries from it sooner it could have
been salvaged. I never did figure out exactly what the operating voltage
was to get mine working again. 5V would be a good start but who knows? If
they went to that much trouble it's hard to say what bonehead, proprietary
logic was in the calculator itself. The AC adapter was something like
11V--obviously it didn't run at that voltage.

-- 

Terry Bowman, KA4HJH
"The Mac Doctor"

"Damn, damn, damn, DAMN!"--Prof. Henry Higgins, "My Fair Lady"--or was it
one of Shaw's?