[sdiy] math question - somewhat OT

[harrybissell]

Hiya Terry (et al)


>
> 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.

Yes you are (essentially) correct)  My pack died that death... and replacing
the nicads did not help. There was some form of primitive chip (of unknown
type) and it was dead too.

I stripped out the guts and put a regulator in there to make the same voltage
that the ni-cads would have given (had they been able to charge...) and it
works great.

Too bad its just a TI-30... but still its a calculator and handy next to the
computer
when I want to multiply by .03937 or some sh!t like that

H^) harry

>
>
> --
>
> Terry Bowman, KA4HJH
> "The Mac Doctor"
>
> "Damn, damn, damn, DAMN!"--Prof. Henry Higgins, "My Fair Lady"--or was it
> one of Shaw's?