HP28S hardware hacking help?

[Christof (Davis, CA)]

Well, I've managed to get a small pile of used and damaged hp28s calculators (okay, small pile == 2, plus a marked up but really clean one).

SO now is time to start the hacking-

Battery compartments (I'll try this first on the 19bii that is similarly damaged). I am thinking of taking material off the LEFT casing to cover the battery port cover area- careful cutting and gluing and it should still close in the proper fashion. Any other ideas on that? These damaged battery cover areas are sucky.

The rs232 serial port hack and software... anyone have any idea at all where to get the information on this? I've read reviews, but can't find any plans or code anywhere....

thanks,
Christof

[Christof (Davis, CA)]

Well, I might have found something, if I can decipher the french it's written in. It appears to describe external power, ir I/O, and serial hacks.

I was unaware of the possibility of ram upgrades in hp28 calcs. Anyone know about this?

-Christof

[Ellis Easley]

Didn't the 28C have less RAM than the 28S? Maybe the 28C could have its RAM upgraded.

[Christof (Davis, CA)]

Well, the manual looks like it might be referring to 28c exlusive ram upgrades, but it's also talking about 64k upgrades! (this would be cool)