Error 3: Statistical Register(S) Unavailable; Error 4: Improper Line Number; Error 5: Improper Register Number; Error 9: Service - HP -10C Owner's Handbook Manual

Note: Error 2 is also displayed if division by zero or the square
root of a negative number would be required during computation
with any of the following formulas:

Error 3: Statistical Register(s) Unavailable

Registers R through R
0
currently converted to program memory.

Error 4: Improper Line Number

Line number called for is currently unoccupied, or nonexistent (>79), or you
have attempted to load more than 79 lines of program memory.

Error 5: Improper Register Number

Storage register named is currently converted to program memory, or is a
nonexistent storage register.

Error 9: Service

Self-test discovered circuitry problem, or wrong key pressed during key test.
Refer to appendix C.

Pr Error

Continuous Memory interrupted and reset because of power failure.
Appendix B: Error Conditions
unavailable for statistical computations because
5
95