|Anyone interested in HP-15C memory upgrade?|
Message #1 Posted by Eric Smith on 3 Aug 2006, 6:40 p.m.
I'm considering offering a hardware upgrade kit for the HP-15C, which would approximately double the available memory (128 "pool" registers, vs. 64 of a standard HP-15C). This could be used for larger programs, larger matrices, more data registers, or any combination thereof.
The drawback is that it would decrease the battery life. I'm not sure by how much, but probably not more than a factor of ten. Given how long the battery life is in the standard 15C, this should still be worthwhile for those who want more memory.
The upgrade kit would consist of a tiny PCB (supplied fully assembled) to be installed inside the 15C. It would require soldering to eight pins of the ICs already in the 15C, and lifting one pin (or cutting one trace).
Installation needs to be performed by someone skilled at SMT rework. I am NOT going to offer a service to install these, but perhaps someone else will. Installation in early 15Cs that have the display and electronics module separate from the keyboard PCB will be significantly more difficult than in later single-board 15Cs. However, the late two-chip 15C boards are NOT compatible with this upgrade.
I don't know exactly what the price of the kit will be, but it will definitely be under $100 (installation not included).
Edited: 3 Aug 2006, 6:42 p.m.