HP-41C with Tall Keys?

[Dan Grelinger]

I purchased an HP-41C recently just to have a spare unit to leave on my desk at work without worrying so much about losing a valuable calculator, and when I got it, I found that it had a serial number starting with 1932, and it had the 'tall keys'. It's in very good shape, and now I am wondering if this is really the -41 I should be using for my intended purpose. I've never really had an interest in this early of vintage of a -41C, and don't know if they are worth any more than subsequent, and more common, standard keyed models. If it is, I probably should get a different model, and put this one up for sale.

Any help on this one?

Dan

[PeterP]

Dan,

It might be a very cool calc. Do a 49, STO 01 and do a SF IND 01 to see if it has the Bug 3 (i think) - the BAT indicator should turn on. If so, it probably has all bugs. I was lucky to find an all-bug 41C in my hands one day and have it similarly safely stored away as some of my other calcs.

This page has all the bugs listed if you scroll down

HTH

Cheers

Peter

Edited: 1 May 2009, 2:10 p.m.

[Dan Grelinger]

Peter,

I hadn't thought of checking the ROM versions. I have an HP-41 Diagnostic module, I'll check the ROM versions this evening.

Dan

[PeterP]

cool, I'll keep my fingers crossed for you. 1932 is a very early number and if you can turn on the BAT indicator, you should be in good shape to have an all bug 41!

Cheers

Peter

[Dan Grelinger]

The HP-41 Diagnostic ROM reports ROM ID DDE. I verified the ability to set system flags using indirect flag functions. I could not duplicate the ability to STO and RCL INDirectly into non-existent registers. The couple of attempts I made resulted in "NONEXISTENT", as a bug-free HP-41 would report.

And a correction, the Serial number begins with 1933 instead of 1932. Fifth character is an 'A', so I guess it is a USA made model.

Dan

[PeterP]

Hmm, that is odd. According to the list at the link above, rom version DDE has all bugs. And bug 3 (the set system flags bug) was the first one to be removed. Last but not least, the first calcs without bug 3 have a serial number of 1936 I think. So on all three accounts it would appear that your calc is an all bugs calc that should allow you to 'sto' into program memory.

[Dan Grelinger]

I verified that bugs 1,3 and 4 exist. If I set size to one, store 1 into register 00, and STO or RCL IND 00, I get 'NONEXISTENT'. Do you get something different?

[PeterP]

Dan,

I just tried mine and it works. From the PPC J V6 N5 P28

Quote:

---

[...] Test as follows. from 'MASTER CLEAR', SIZE 000. No data registers. Key 999, ENTER, PI. Now store Pi indirectly in register 999 by: STO IND Y. Clear the stack. Recall Pi by 999, RCL IND X

---

In the Wickes book on p2 it says that it works for regs 719 to 999 through some kind of 'wrap around'...

HTH

Cheers

Peter

Edited: 4 May 2009, 1:43 a.m.

[Dan Grelinger]

OK, I didn't try registers 719 to 999. I'll try those when I get home.

I have never watched the selling prices for an early version HP-41C. Are they significantly higher than a normal 41C, which in my experience has been ballpark $100 in good condition with original box and accessories?

Dan

[Dan Grelinger]

Yes, the -41C will allow me to access 'register 999' indirectly.

[PeterP]

Congratulation!