8 Mar
2003
8 Mar
'03
12:56 p.m.
Jos,
You have a bad Data Storage IC. Depending on which version board
is in your 41 it may have from 1 to 4 DS ICs but they are custom built
Didn't some HP41s haev 5 RAM (Data Storage) ICs? Each one 16 registers
long (one for the 'status registers', 4 for the 64 user registers?
ICs made by HP specificly for the HP 41 so you'll
never find one. Time
A trick that works when you have a CV with one of the 'extra' DS chips
failed (that's to say one of chips that hold registers after the first
64), is to crack open a single memory module (which are really common!),
then extract the 'PCB' and wire it inside the 41, in place of the bad IC.
Solder the B3 and B4 lines to put it at the right address. Yes, it's a
kludge, but it works. And alas it's not applicable in this case.
to find another 41 for parts. There are plenty of htem
out there that
have broken displays, bad power supply ICs and/or corroded battery
terminals.
Perhaps I've been lucky, but I don't think I've ever seen a bad PSU chip
in a 41. Bad CPUs I've had, though.
Damaged battery contacts can be kludged over with a bit of care, so
that's not a reason to regard a 41 as a 'parts' machine...
-tony