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HP 41CX Halfnut CX EXT FCN missing - Printable Version

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HP 41CX Halfnut CX EXT FCN missing - HPnerd - 10-26-2021 08:55 AM

Hi all, maybe you can bring light in my problem:

i changed the backplane pcb due corrosion and missing lanes at my HP 41CX 2652Sxxxxx.
The donor of the backplane was a working CV 2818Sxxxxx (without the CX-addon pcb).
After changing the backplane the calculator was a nice "CV", okay i soldered the CX-addon pcb, a TIME 2C and CX TIME was added - but no EXT FCN nor a CX EXT FNC!
The additional catalogs 4,5 and 6 are missing as well...

So i did a rework of the ROM at the main pcb - now everything execpt the main pcb (same partnumber) was "CX" - but still the same - no ECT FCN nor CX EXT FCN nor catalogs...

Where the hell is the CX EXT FCN located at the Halfnunts?

Thank you for your answers, best regards from Austria
Walter


RE: HP 41CX Halfnut CX EXT FCN missing - BillBee - 10-26-2021 11:46 AM

This thread should help you.

https://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv014.cgi?read=70045

3rd one.

-Bill


RE: HP 41CX Halfnut CX EXT FCN missing - HPnerd - 10-28-2021 06:15 PM

Thanks Bill,
You did make my day :-)
i did not loose any thought about the display-pcb to hold any ROM...
so i have to completly remove the key-pcb again to change the display-pcb :-( but i think it is worth to do so :-)
Thanks a lot for this value information, again best regrads from Austria
Walter