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Arne Helme

03-14-2006, 10:06 AM

I have an early version HP-41C with serial number 1939Axxxxx. According to information found on:

http://dan.pfeiffer.net/hp41/hp41info.htm

the calculator contains either a DDE ROM with all the "classic" bugs or a FDE ROM with all bugs except bug #3.

How can I determine whether the calculator has a DDE or FDE ROM? Based on some trials it is evident that the calculator has the #1 bug. However, I am not able to detect either the #2 or #3 bugs. If I understand the information referred to above correctly the calculator should have at least one of these bugs as well, right?

Can someone provice me with the exact steps required to detect the #2 and #3 bugs?

I also have the PPC ROM. Can I use if to read the calculators ROM version?

Regards,

Arne

Gene

03-14-2006, 10:31 AM

Bug 2: Do this: 997 ENTER 1.23 STO IND Y

If it errors out, you do not have bug 2.

If it seems to work, congrat's...you have bug 2.

Bug 3: 49 STO 00. SF IND 00.

If it errors out, you do not have bug 3.

If it seems to work (by turning on the low battery indicator), then you have bug 3.

Much easier/quicker than viewing the ROM versions. :-)

Arne Helme

03-14-2006, 10:37 AM

Thanks for the info! The calculator has the #2 bug but not the #3 bug.

Arne

HP Forums > HP Museum Forums > Old HP Forum Archives > How to detect early HP-41C ROM versions/bugs?