Post Reply 
HP48 card PCBs
12-08-2021, 08:58 AM
Post: #1
HP48 card PCBs
Some years ago there were hobbyist-produced RAM cards for the HP48 line. I got my hands on one of these and I seem to have lost it. Has anyone ever documented any of these cards? I'd like to see about crafting my own.

David Griffith
Find all posts by this user
Quote this message in a reply
12-08-2021, 12:32 PM
Post: #2
RE: HP48 card PCBs
You can find one example in my github repository here

https://github.com/mafleming/HP48RamCard

A commercial version of a card is discussed in this thread

https://www.hpmuseum.org/forum/thread-17140.html

Somewhere else in the forum is a thread where a member posted a clever solution using a stack of thin PCBs to get a physically correct memory card shell.

~Mark

Remember kids, "In a democracy, you get the government you deserve."
Find all posts by this user
Quote this message in a reply
12-08-2021, 11:16 PM
Post: #3
RE: HP48 card PCBs
I was thinking mainly of this design:

https://www.hpcalc.org/hp48/pc/pictures/kk2048.jpg

The one I lost is of this design with fewer chips populated.

I think this one (https://www.hpcalc.org/hp48/pc/pictures/stolte20.jpg) is the stacked PCB design.

David Griffith
Find all posts by this user
Quote this message in a reply
12-15-2021, 03:32 AM (This post was last modified: 12-15-2021 03:34 AM by GreyUser.)
Post: #4
RE: HP48 card PCBs
I have a 128kb and 512kb card of the stacked board construction shown (actual layout slightly different). It too has the glue logic chips tops sanded/scratched off but I would expect it wouldn’t be too difficult to reverse engineer them.

What info are you looking for? Schematic? Other?
Find all posts by this user
Quote this message in a reply
Post Reply 




User(s) browsing this thread: