Faulty Double X Memory Module (HP-41)

[Archilog]

Hello HP fans,

I've bought years ago a DBL-X-MEM module in working order.

Yesterday I checked it on a 41CV with X Functions module and today on my 41CX.

In both machine an EMDIR or Cat 4 returns 'Dir Empty' and 362.0000 in register X. It should show 600.0000 (124 on CX or XFM and 2x238).

I am able to write and purge files onto the module, but it seems that some banks (I do not know if the word is appropriate) or some connections are faulty. So my two questions:

- Did this problem already happen to you, or did you hear about a similar one? I didn't find any story about that on the Forum.
- Is it possible to open the module to verify and fix this memory failure?

Many thanks,

Archi.

[KimH]

My suggestion is that one of the controlling wires to one of the two memory modules in your casing have suffered. The math seems to fit -- 124+238=362

Double memory are usually (like 100%) made from combining two single modules' PCBs into one casing. Thin wires and cramped space.

You can find an explanation HERE

Undoing this is not for the faint of heart who has no experience with this

(02-25-2021 11:45 AM)Archilog Wrote:  Hello HP fans,

I've bought years ago a DBL-X-MEM module in working order.

Yesterday I checked it on a 41CV with X Functions module and today on my 41CX.

In both machine an EMDIR or Cat 4 returns 'Dir Empty' and 362.0000 in register X. It should show 600.0000 (124 on CX or XFM and 2x238).

I am able to write and purge files onto the module, but it seems that some banks (I do not know if the word is appropriate) or some connections are faulty. So my two questions:

- Did this problem already happen to you, or did you hear about a similar one? I didn't find any story about that on the Forum.
- Is it possible to open the module to verify and fix this memory failure?

Many thanks,

Archi.

[Archilog]

Oh, that's fine, thank you Kim, I didn't notice that PDF.
I'll first open the module to see what to do and if it's in my skills.