Memory expansion on GX


This might sound dumb, but is memory cards for the GX available that doesn't use a backup battery.


I don't think so but there's an easy way to test it. Just remove the batteries from your card and I think that the card will use the calculator's batteries to keep data. Disable message errors when you start the calculator. The problem is that the 48 series canno't use flash memory but RAM memory instead. RAM needs to be permanently powered and if you doesn't have enough power, the card will use the unit's power.
I hope it will help you.
Best regards,


Not that I know of, but the newer SMI RAM cards have a rechargeable "10-year" battery. It's recharged from the AAA cells, provided that they're strong enough. My impression is that the 10-year battery is non-replaceable, but I may be mistaken about that. How well it works out, for example, what happens if the 10-year battery is allowed to go completely dead, I don't know. See:

How to Resolve the HP 48 "low battery p(2)" Message

I don't expect that flash memory would work with the 48 design without extensive modification.



I saw somewhere that there was Flash Cards for HP-48...


I used EPROM cards for my SX and GX:-)



I used EPROM cards for my SX and GX:-)
Ah, good point!

But I assumed that Ric meant "RAM" cards; that is, memory that could be both read and written in the calculator.



How did you that Raymond????


Long time ago EPSON sold suitable 8bit EPROM cards to OEMs.

If you are lucky having bought a W&W software card for the HP-48,

like the Assembler ROM, or the Surveying Pac,

you're likely to have an EPROM card:-)

At W&W we used an EPROM burner called SprintPlus,

at home I used a small ISA slot unit called PB-10 from Needhams's Electronics.

Both have optional slots/sockets for those EPSON cards.

There were several ways to produce the image needed for the EPROM.

The easiest way was to read the contents of an HP-48 RAM card into the burner buffer,

then burning the buffer contents.




Many thanks Raymond, now I understand.

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