Santron Santronic 600PM

Datasheet legend
Ab/c: Fractions calculation
AC: Alternating current
BaseN: Number base calculations
Card: Magnetic card storage
Cmem: Continuous memory
Cond: Conditional execution
Const: Scientific constants
Cplx: Complex number arithmetic
DC: Direct current
Eqlib: Equation library
Exp: Exponential/logarithmic functions
Fin: Financial functions
Grph: Graphing capability
Hyp: Hyperbolic functions
Ind: Indirect addressing
Intg: Numerical integration
Jump: Unconditional jump (GOTO)
Lbl: Program labels
LCD: Liquid Crystal Display
LED: Light-Emitting Diode
Li-ion: Lithium-ion rechargeable battery
Lreg: Linear regression (2-variable statistics)
mA: Milliamperes of current
Mtrx: Matrix support
NiCd: Nickel-Cadmium rechargeable battery
NiMH: Nickel-metal-hydrite rechargeable battery
Prnt: Printer
RTC: Real-time clock
Sdev: Standard deviation (1-variable statistics)
Solv: Equation solver
Subr: Subroutine call capability
Symb: Symbolic computing
Tape: Magnetic tape storage
Trig: Trigonometric functions
Units: Unit conversions
VAC: Volts AC
VDC: Volts DC
Years of production:   Display type: Numeric display  
New price:   Display color: Red  
    Display technology: Light-emitting diode 
Size: 6"×3"×1½" Display size: 8 digits
Weight: 6 oz    
    Entry method: Reverse Polish Notation 
Batteries: 3×"AA" alkaline Advanced functions: Trig Exp 
External power: Santron adapter   Memory functions: +/- 
I/O:      
    Programming model: Keystroke entry 
Precision: digits Program functions: Cond  
Memories: 1 numbers Program display:  
Program memory: 102 program steps Program editing: Step delete capability  
Chipset: NS MM5760N   Forensic result: 8.843762  

s600pm.jpg (44179 bytes)What a delightful old calculator! Many, many thanks to Niels Wittje from Germany who, instead of turning this poor old machine into useless e-waste or putting it up on eBay in the hope of getting rich on the proceeds, donated it to our site.

At first, I thought I was confronted with an entirely unique beast, but that is not the case. Though its appearance is different, this calculator is really identical to the National Semiconductor NS-4515 Mathematician.

This 600PM has an odd affliction that, at first, I thought was a design error: numbers less than 1 are displayed with the leading zero suppressed (which is okay) but with the decimal point after, not before, the first digit. Initially I was under the impression that only numbers between 0.1 and 1 behave this way but no: all fractional values do. And closer inspection shows that the decimal point is significantly fainter than normal. So perhaps it's not a logic error, after all, just some analog cross-talk, perhaps some contamination or corrosion of the main PCB? I was able to open the case cleanly and while there was plenty of corrosion near the battery terminals, there were no other obvious signs of damage.

This particular machine also appears... much loved? It seems that several of its keys have been customized. There are also some near-professional quality labels above and below the display that are not factory originals; similarly, some custom labels are also present on the back of the calculator. Given the quality of the labeling and their obvious utility, I decided to keep the calculator "as is" rather than attempting to restore it to a more "factory original" appearance.

Beyond these customizations and the weird display bug, however, it really is the NS-4515 throughout. In particular, the program for the log Gamma function that I wrote for the NS-4515 works on the 600PM without alteration. Just like on the NS-4515, it is fairly accurate for arguments greater than 1: For instance, 5 start yields 24.00004 after exponentiation, which is pretty darn close to the correct result, 24.

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