HP-41CX with built-in HEPAX module

[Jurgen Keller]

Today I got an HP-41CX for testing/refurbishing. After inserting batteries I was happy to see that it still works perfectly. However, I was quite surprised when I did a CAT 2 and saw '-HEPAX 1C' on the display. So it looks like this 41CX has a built-in HEPAX module! Quite cool, a very uncommon modification, at least I never saw such a variant before. Furthermore, it has a red switch on the left side to enable TURBO mode as you know it from 41CYs, for example. HEPROOM displays 2610 so my understanding is that it's a 16K HEPAX module, right? Does anybody know of such a modified 41CX? If so any background information will be highly appreciated.

Sorry, have to stop here and play around with this special 41CX! :-)