Hi, F Farmer;
you can actualy see the keycodes and take note of them for later decoding and bringing back the keystroke sequences that generated your program.
Some precautions: while in PROGRam mode, NEVER press [f]CLEAR[PRGM], because this is just going to clear all programs from meomory; also, NEVER press any other keys but [g][P/R] (to get in and out of program mode), [SST] (to go forward a Single STep) and [g][BST] (to go to the previous step; Back STep).
After turning your HP15C ON, locate the [R/S] key right over the [ON] key, and you'll see the [P/R] inscription on it (slanted front face). Press [g][RTN] (beside the [R/S] key) to bring program counter to step 000 in a safer way, then press [g][P/R], so the display shows:
[ 000- ]
and the little PRGM indicator becomes active (your HP15C is in PROGRam mode; rememeber the only keys you shoud press, now...)
Press [SST] one time and it should show:
[ 001-xx xx xx]
The xx xx xx indicates some number code related to the keys that were pressed in the beginning of the program. Chances are you have something like:
[ 001-42,21,11]
meaning the first program step is:
[f] (4th. line, 2nd. row in the keyboard)
[LBL] (2nd. line, 1st. row in the keyboard)
[A] (1st. line, 1st. row in the kwyboard)
If you take note of all keycodes you see after pressing [SST], you can rebuild the program. If it is a survey program, I'd expect something less-than or close to 100 steps, maybe some more, depending on which features it shows and how does it handle data.
If you need more advice or extra help translating the program, let us know.
And aways beware of using any other keys but the ones mentioned while in PRGM mode.
Success!
Luiz (Brazil)
Edited: 28 Nov 2005, 8:45 a.m.