Strange behaviour with MATDIM (Advantage ROM) on NoV-64D

[emefff]

Hello,

first post here, although long-time user of many different HP Calcs.

A friend of mine brought this to my attention, because he needs to go 'back to the roots' on some digital design project. The task is to get the inverse of some special matrix in hardware and finding a good algorithm for that. I said: we can even try that on a HP-41, even doing some algos from numerical recipes etc.

However, I wanted to try the built in algorithms in the Advantage ROM first. On page 54 of the Advantage ROM manual there's a neat example. If I go through that on a 41CX with NoV-64D in port 1 (Advantage ROM is burnt to it the usual way according to NoV-64D manual, just pressing the button and burning it. Source of these ROMs is Monte's ROM files rom_files_240109.zip) and REAL MATH 1 ROM in port 2 (SIZE? = 50):
INPUT:_________________ DISPLAY:
FIX 4__________________ "0.0000"
ALPHA R0 ALPHA _______"0.0000"
3.003 XEQ MATDIM ______"0.3003" (This is VERY wrong!)

The last line should give "3.003". Also if I try DIM?, the calculator changes the . to , and behaves strangely. The I pressed PRGM and subsequently I couldn't turn it off. I had to remove the batteries briefly. The real MATH rom does not have any influence, I tried. Of course, there is no usable matrix that I can actually enter any numbers into.

I also converted the ADVANTAGE.MOD from hp1.org into 3 .ROMs with Christoph Giesselinks MODFileWin.exe and flashed this to the NoV-64D. Same result, the converted ROMs are the same like Monte's, bit by bit I checked afterwards with sha512sum.

Anybody having experienced this? If I do that on the DM41X I get the correct number displayed (MOD file supplied by Swissmicros) and can actually use this matrix, also on a 41CV with a REAL Advantage ROM in port 1.

I do not know what is wrong here, could my 41CX be in some mysterious state? Are the 3 Adv.ROM files in Monte's library erroneous, as is the ADVANTAGE.MOD on hp1.org (possibly both files from same source). But then, where did the .MOD Swissmicros uses come from?

Can anybody try that with Advantage on a NoV-64D?

Thanks in advance,

emefff.

EDIT: In the meantime I checked by switching NoV-64D to the 41CV and putting the real Advantage into the 41CX. The NoV-64D is definitely the culprit, not the 41CX.