Rambox battery replacement



Can someone enlighten on how to replace the backup battery in a RAMBOX unit (housed in card reader shell)? Thanks folks.

Best regards,



Dear Prabhu,

The following will detail to you how I managed to save and run all my software developped on a RAMBOX. It may not be the exact answer to your current problem ( internal battery replacement ) , but it offers a way of getting around it.

A few years ago I was in a situation quite similar to yours : I needed to have one HP41CY ( i.e. a HP41CX with an internal RAMBOX II version with 64 K ) repaired. It was not a question of internal battery replacement, but it was a faulty and erratic behavior with a suspected internal wiring degradation which definitely required internal repair.

The following describes the way I solved my HP41CY / RAMBOX II problems in a totally unexpected way, which eventually has been MUCH BETTER than a simple product repair and exceeded all my expectations thanks to the highly dedicated work of a few Men as described hereunder.

If you proceed like I did, maybe it will help you as much as it helped me.


As you know RAMBOXes were manufactured by the German Company W & W Software Gmbh. When I needed a RAMBOX II repair some 5 years ago, Wilfried Koetz the Manager of W & W Software Gmbh indicated to me that W & W had stopped supporting the RAMBOX.

As I had extremely important software on my Rambox II - a software I had taken some 3000 hours to develop - I had to find an urgent solution ...




The here-above story describes how I solved my RAMBOX II problems in a totally unexpected way, which eventually has been MUCH BETTER than a simple product repair.

In other words : if you have the possibility of using one of the existing available " HP41 Simulators " which 100% replicate the 64 k RAMBOX I/II, you should then be able to run all your own Software existing to-day on your RAMBOX.

In my own case, I am fully indebted to both Jean-François Garnier and to HrastProgrammer. As the STORY herebaove goes, and simply because I requested some help from them , Jean-François greatly improved his former EMU41 into fully replicating
the full 64K RAMBOX II and making it available to the Community. And on his side HrastProgrammer went into developping for me a taylored version of his HP-41C Emulator for HP-48GX/49G into a Version with a total of 92 K - including a full replica of the 64K RAMBOX II.

True .. you would need to get a HP48GX with some memory cards, or a HP49G ( or a HP49G+ or a HP50 : Please HrastProgrammer correct me if the references to HP49G+ and HP50 are not correct ) if you want to have a HANDHELD replacement of the Rambox I / II ... ( see HRASTPROGRAMMER SITE and in particular HP-41C Emulator for HP-48GX/49G ) .

... but if all you want is keeping a record of your
Programs working on a laptop - at a speed of over 500 times a real world HP41 - then Jean François Garnier's superb " EMU41 running on PC " is a wonderful choice ( see EMU41 )

Hrastprogrammer's HP41 X/Y/Z - under the Version developped specifically for my own needs as described in the STORY hereabove - and Jean-François Garnier's EMU 41 emulators are the only 2 emulators I know of which fully emulate Rambox I / II .

I am not aware of any other such emulator ( i.e. replicating the Rambox I / II ) . But should one exist, its existence will likely be confirmed to you on this forum by any qualified Expert reading this thread.

I hope this information will be useful to you.

Best Regards from


Edited: 17 Oct 2007, 3:29 a.m.


Bonjour Antoine,

Nice to hear from you!

Any chance for everybody to see oneday your "extremely important software [you] had taken some 3000 hours to develop" ?


Edited: 19 Oct 2007, 3:17 p.m.


Hello Jean-François,

Thank you for your very kind words.

My ASTRONOMICAL NAVIGATION Software User's Manual is still under construction : it is amazing that things so clear in my mind take quite some time to summarize in a way both complete and concise, so that unfamiliar readers get a quick understanding about how to use it.

I have already structured it into 3 parts :

1 - Quick User's Guide

2 - Memory Allocation Table and General Equations used + General Navigation considerations

3 - More Detailed data and in particular :

3.1 - Theories used, Acknowledgements to various Astronomers / Engineers, accuracy versus validity of the Astronomical algoritms used,

3.2 - Improved mathematical methods where to the best of my knowledge no equivalent algoritms have been published so far,

3.3 - Some details on programming since for instance my " Mean Elements " Program can be run in 6 different ways, with all the various computation results being monitored through various flag settings,

3.4 - and possibly more ...

Best Regards from


Edited: 20 Oct 2007, 6:05 a.m.

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