|HP-41CV Keyboard/Behavior Weirdness|
Message #1 Posted by Paul Brogger on 2 Apr 2003, 10:13 a.m.
I think I've read the repair & reset articles about the HP-41, but am not sure whether my unit's behavior will be addresed by those techniques.
When first turned on, it seemed to be operating o.k. (With the batteries in the first time, it came up with "MEMORY LOST".) Fine. Then I thought, "I wonder how this thing programs?" I push PRGM, and the first display looked like a programming interface -- a line # in the 230-ish range, with some symbol that looked appropriate, but which I can't remember.
I started to SST, and things got weird. there are two or three three-digit numbers (generally, I think, in the 233-9 range) arranged on the screen, and as I SST, they shift to the right and change values . . . Very bizarre user interface, if that's what was intended.
Anyway, after having done this, I go back to normal mode and the keyboard is all messed up. I push a "1" and get a "9" -- I push the "2" and get a "." -- very quickly the cursor shifts to the exponent digits on the right -- bizarre non-alphanumeric characters appear . . .
I tried the "reset" techniques described in the MoHPC article -- the simultaneous back-arrow/enter/ON thing seemed to work once -- the keyboard started behaving normal-ish. But when I went back to PRGM mode and started SST (some people never learn!) the same result happened, and the keyboard is messed up again. (That, and the back-arrow/enter/ON technique hasn't worked a second time.)
Other things I've tried: -- varying degrees of tightness on the screws; -- cleaning the contacts with 91% isopropyl alcohol; -- shorting the outside battery contacts. (If prayer is recommended, I might consider "getting religion" . . . )
I'm faced with a partial refund situation here -- if the "soldering-the-cpu-to-the-keyboard" approach might help here, I would keep the calculator. If it looks like PRGM memory or ROM is messed up, locking the calculator, then I suppose I'll cut my losses.
Any other suggestions/links?
(BTW, this is Fullnut S/N 2408S41073.)
Thanks . . .