[HP-48GX] Expansion slot info needed

[rprosperi]

Retrotronik in Portugal makes and sells cards in 128KB, 1MB and (eventually) 2MB sizes, at quite acceptable prices:

https://retrotronik.com/

Note that sometimes it takes a while to get replies, so be patient, you will get a reply.

If you proceed to making a card I strongly suggest you get your hands on a actual card (buy a dead one) as the keying for the channel where the connector mates deep within the slot is neither documented well nor easily described. This unexpected aspect has foiled more than one DIY-er attempting to make 48 cards.

Good luck