Cantares Virtual Calculator Museum

Michael Dunn's Museum of Calculators and Other Oddities

I've been enthralled with calculators since I played with one of the first pocket ones around 1972. They strengthened an already strong interest in math and taught me my first lessons in programming (I think my first actual programming experience was on a Compucorp, card reader and all, at school). Over the years, I've built a decent little collection. Some work, some don't. Some were bought to use, some acquired as collectibles. They are arranged in rough chronological production order. Don't take any of the data here as gospel. There are some approximated entries. If you can correct anything, let me know. Click on the thumbnail to get a larger image. Costs are in Canadian dollars. The "Forensic #" is a quick test to gauge the accuracy of the trig algorithms, the number of internal digits, and sometimes even the chip (set). The ideal result is 9. Check the site for more info (a couple of my results for non-working units were taken from this site). The "69!" entry (get your mind out of the gutter) gives the time to calculate the factorial of 69. Last updated July 29, 2004.

Click here to see a calculator book published in the UK in 1976 and republished by Coles Bookstore (Canada) in 1980.

Click here to see a TI calculator book from 1978.

Manufacturer Wang Labs	Model LOCI-2 (2A)	Mfg. Date 1967 (s/n 3059)	Accession Date ~1982	Orig. Cost ~$3000	Batteries	Made in USA
Display Nixie tubes	Programming 80 steps (1 per keystroke), punched card	Digits (guards) 10		Forensic #	69!	Fractions
Stats	Non-decimal	Memory 16, continuous (magnetic core)	Conversions
Comments A breakthrough calculator, this has a log-antilog-computing circuit at its heart. Therefore, multiplication and division are done internally as log-add-antilog! Of course, this enables the relatively simple inclusion of functions like square and square-root in addition to log and antilog. Circuitry is entirely discrete transistor (over 1,200); not a single IC. There is no program memory per se. Instead, the card reader has a contact for every possible hole position, and the card itself becomes a ROM! Very cool. Here are the manuals.

Manufacturer Rapid Data Systems & Equipment Ltd.	Model Rapidman 800	Mfg. Date 1972 (s/n 122762)	Accession Date Apr 2004	Orig. Cost $100? ($400!?)	Batteries 9V	Made in Canada
Display LED	Programming	Digits (guards) 6.2/8.2		Forensic #	69!	Fractions
Stats	Non-decimal	Memory	Conversions
Comments One of the earliest readily available machines, I think this might be the first calc I ever had a chance to sit and play with. Odd olive/khaki colour, I think it also came in black. It's a bit of a chore to use. You have to clear it before doing a +/- calculation or else the previous result will get used in an RPN-ish manner. In fact, doing addition and subtraction is just like RPN, which is also how many mechanical adding machines worked I guess. See the instructions on the back. The keys have a cool feel, with the numbers being recessed about 1mm. The display is fixed at two decimal places, but, you can use numbers >999999.99 (only millionaires would need to use such numbers, and there were fewer of them in 1972). When you exceed the display's capacity, the indicator to the right of the display comes on, indicating 1 or 2 undisplayed MSDs. When you're finished, divide by 100 to see the integer part. Overflow beyond 8.2 and you see 0 0 0.0.0.0.0.0.

Manufacturer Royal (Litton)	Model Digital V	Mfg. Date 1972-1973	Accession Date	Orig. Cost	Batteries Internal NiCds	Made in Japan
Display Green VFD	Programming	Digits (guards) 8		Forensic #	69!	Fractions
Stats	Non-decimal	Memory	Conversions
Comments

Manufacturer Victor Comptometer Corp.	Model MEC/1	Mfg. Date 1973	Accession Date ~2000	Orig. Cost $280	Batteries 6 AA(?) internal NiCds	Made in USA
Display Burroughs Panaplex II planar neon	Programming	Digits (guards) 12		Forensic #	69!	Fractions
Stats	Non-decimal	Memory	Conversions
Comments You've gotta love those Panaplex displays... Also has an AC power cradle (not shown).

Manufacturer Simpson-Sears	Model Digimatic 41007	Mfg. Date ~1973	Accession Date Mar 2004	Orig. Cost	Batteries 3 AA	Made in Hong Kong
Display LED	Programming	Digits (guards) 8		Forensic #	69!	Fractions
Stats	Non-decimal	Memory	Conversions
Comments Labelled/built for Simpson-Sears (Canada), this calc found its way to Australia and back again. The batteries don't really fit well. Have AAs gotten longer in the last 30 years?

Manufacturer Sharp	Model Elsi Mate EL-120	Mfg. Date 1973	Accession Date Mar 2004	Orig. Cost	Batteries 3 AA	Made in Japan
Display Green VFD	Programming	Digits (guards) 9.3 (3 physical)		Forensic #	69!	Fractions
Stats	Non-decimal	Memory	Conversions
Comments The weirdest calc I've ever known. The button on the side increments the display by 1, like a person counter clicky thing. On top of that, the display is only 3 digits! If the number is longer than this, the display flashes between groups of digits, either automatically or manually. Up to 4 groups might be displayed - 3 to the left of the decimal, 1 to the right. "Comma" graphics indicate which group is showing. Click here to see an animation of the display in auto mode. The build quality is quite rugged, and there's a cm scale molded into the back. Maybe this was meant for shop use??? Inventory taking??

Manufacturer Melcor	Model 400	Mfg. Date 1973-1974	Accession Date 1974	Orig. Cost ~$80	Batteries 9V	Made in USA
Display LED	Programming	Digits (guards) 8		Forensic #	69!	Fractions
Stats	Non-decimal	Memory 1	Conversions
Comments My main calculator for a while. I quite liked its look and feel.

Manufacturer Novus	Model 650	Mfg. Date 1975	Accession Date ~1975	Orig. Cost $20	Batteries 9V	Made in USA
Display LED	Programming	Digits (guards) 6		Forensic #	69!	Fractions
Stats	Non-decimal	Memory	Conversions
Comments At one point, I had modified this to be a stopwatch (the picture), actually using the calculator circuit (probably why I bought it). I later dismantled and gutted it, and built a binary counter do-nothing-box into it with four LEDs where the display used to be. I don't recall why.

Manufacturer Microlith	Model Scientific 205	Mfg. Date 1974-1976	Accession Date 1974-1976	Orig. Cost	Batteries 9V	Made in Hong Kong
Display Blue VFD	Programming	Digits (guards) 8+2 (0)		Forensic # 6.58003	69! 5s	Fractions
Stats	Non-decimal	Memory 1	Conversions deg/rad
Comments Trigs and logs computed to 6 digits. Interesting exchange key <-> exchanges display with last-entered number.

Manufacturer Novus (National Semi)	Model Mathematician 4510	Mfg. Date 1975	Accession Date	Orig. Cost	Batteries 9V	Made in Malaysia
Display LED	Programming	Digits (guards) 8 (0)		Forensic # 8.843762	69!	Fractions
Stats	Non-decimal	Memory 1	Conversions
Comments A very interesting calc. A rare non-HP RPN machine! Amazingly for a scientific, NO exponent! Trig and some other functions only computed to 7 digits. Even integer exponentiation is inaccurate (e.g., 2^16=65535.82!). Power saver switches display to all decimal points after about 25 seconds. Has a key to sum square of display into memory.

Manufacturer Texas Instruments	Model SR-56	Mfg. Date 1976	Accession Date Jan 1977	Orig. Cost $200	Batteries 3 AA NiCd in cartridge	Made in USA
Display LED	Programming 100 steps (1 per keystroke), volatile	Digits (guards) 10+2 (2-3)		Forensic # 9.000004661314	69! n/a	Fractions
Stats basic	Non-decimal	Memory 10, volatile	Conversions
Comments A classic!!! I got lots of early programming experience on this. A great feeling calc. Best thing TI ever did! Can be mated to the PC-100 thermal printer. Interesting - a slide switch for degree/grad selection, but a key command to switch to radians. Click here to see a program sheet for my SR-56 pièce de résistance, a Tug-of-War game. Here's the back. And check out the nice manuals.

Manufacturer Texas Instruments	Model TI-30	Mfg. Date ~1977	Accession Date June 2004	Orig. Cost ~$25	Batteries 9V	Made in USA
Display LED	Programming	Digits (guards) 8/5+2 (2-3)		Forensic # 9.177087103	69!	Fractions
Stats	Non-decimal	Memory 1, volatile	Conversions
Comments A very popular calc in its day. Power saver displays a "walking" decimal point. During long computations (e.g., trig), the RH digit goes through all sorts of neat contortions to show it's thinking. EE key can shift decimal around in either direction in steps of one power of ten. The cute little tick marks in the upper-left are the DRG indicator (none for deg, 1 for rad, 2 for grad). Combine with a negative sign in the left-most position, and you get a strange looking display! Integer exponentiation is inaccurate (2^16=65536.000534).

Manufacturer Commodore	Model PR100	Mfg. Date 1978	Accession Date	Orig. Cost $70	Batteries 3 AA NiCd fixed	Made in England
Display LED	Programming 72 steps (1 per keystroke)	Digits (guards) 8+2 (2)		Forensic # 9.14705679 (12sec)	69! 1.5s	Fractions
Stats 1-var, P&C, LR	Non-decimal	Memory 10	Conversions deg/rad, R/P, H/HMS, metric (4), cartesian/spherical!
Comments Cute display has exponent digits smaller than mantissa. A surprisingly sophisticated machine for the time and price. Here's a friend's working unit. And with manuals.

Manufacturer Texas Instruments	Model TI-58C	Mfg. Date 1980	Accession Date 2000	Orig. Cost	Batteries 3 AA NiCd in cartridge	Made in USA
Display LED	Programming y	Digits (guards) 10/8+2 (3)		Forensic # 9.000004661314	69!	Fractions
Stats 1-var	Non-decimal	Memory 10, continuous	Conversions R/P, H/HMS
Comments This is the continuous-memory version of the original TI-58. The card seen under the display is not magnetic, but simply labels the definable buttons. You can make them for your own programs, or slip in one that comes with a ROM software module. The module I have includes 25 cards! The calc is shown mounted on the PC-100C thermal printer (acc. 2003). Looking at the guts, I noticed that two chips (probably memory) are stacked on top of each other. IBM also once used this trick in a PC (AT?). Pgming model includes flags.

Manufacturer Nixdorf	Model LK-3000	Mfg. Date 1980 (cartridge 1979)	Accession Date 2000	Orig. Cost $170	Batteries 4 AA NiCd fixed	Made in Malaysia
Display 16 chr. alphanumeric LED (14-segment)	Programming	Digits (guards) 7 or 8		Forensic #	69!	Fractions
Stats	Non-decimal	Memory 1	Conversions Language!, metric, currency
Comments A language translator with calculator functionality. I have the English/Polish module. To do calculations, you actually need a separate calculator module. There wasn't enough ROM space to combine calc and language! Modules were also available with PDA or database functionality as well as one containing 1980 Olympics results! Bet that one sold well. Oddly, the module itself contains not only the ROM, but the processor too (a Mostek 3870 microcontroller (Fairchild F8 core)). The display is comprised of four "intelligent" alphanumeric modules. Although I got the unit fixed up enough to power up, the keyboard connector is broken, so for now, I don't know any more about its functionality. Display goes into power-saving mode after ~20s. A 2s exposure is shown in the picture. Here's the unit saying something else. There's a bad display connection too, as the words and power-save display aren't quite "right".

Manufacturer Hewlett-Packard	Model HP-85	Mfg. Date 1980	Accession Date Apr 2004	Orig. Cost ~$4000	Batteries	Made in USA
Display CRT, 32x16 character, 256x192 graphics	Programming BASIC, 14K RAM	Digits (guards) 12+3 (0)		Forensic # 8.99999864267 (0.3sec)	69! 0.5s, as a program!	Fractions
Stats	Non-decimal	Memory	Conversions
Comments More a computer than a calc, it's here because it's H-P, and because it can be used as a calc, simply by entering expressions directly. Also, the processor architecture and speed lean towards calculator-type designs. Although the processor clock is only 613kHz, the architecture is streamlined for math and is a bit RISC-like. For example, the operation r1=r1+r2 takes one clock (well, four phases of one clock, so you might say the clock is actually 2.452MHz). There are 64 registers. It appears to run significantly faster than a contemporary 8080 or Z80 system. 64-line history. Amazingly high integration for 1980, the entire machine consists of 11 LSI chips that do everything - processor, ROMs, keyboard, I/O, video, tape drive, printer. There is essentially NO digital support circuitry. Most of the remaining circuitry is for power and the CRT. Eight 16Kb DRAMs, plus four more for video memory. Dynamic range of 10^+/-499. This example has two plug-in modules, each providing an HP-IB (GPIB) interface. An HP page about it. And another.

Manufacturer Hewlett-Packard	Model HP-15C	Mfg. Date 1984	Accession Date Sept 1984	Orig. Cost $165	Batteries 3 LR44	Made in USA
Display LCD	Programming about 300 steps with 21 memregs	Digits (guards) 10/7+2 (0)		Forensic # 9.000417403 (5sec)	69! 0.75s	Fractions
Stats 1-var, P&C, LR	Non-decimal	Memory 67 max (no pgm mem)	Conversions deg/rad, R/P, H/HMS
Comments One of the best calculators ever made -- by anyone. Shows well even on its 20th birthday (amazingly, the 15's sister calc, the HP-12C Financial, is still being made after over 20 years! Quality never goes out of fashion). RPN of course. Program/register memory trade-off completely under user control. The "C" in HP-15C really means continuous. Even the display is held when powered down. Oddest attribute: No normal floating decimal! Easy enough to get used to, and it's always possible to view the full 10-digit mantissa with a keystroke. Automatic 1000s separators (commas) can be changed to decimal points (decimal becomes comma). I tend to keep it in sci/eng mode with a comma decimal... Original batteries lasted for >12 years. Nuclear? Claims to fame: Complex numbers and matrices. Full implementations - all relevant functions work in complex mode, matrices can be complex. Computes integrals, roots. Does non-integer factorials! Takes a bit over 2 seconds regardless of the argument. Flags and full range of comparisons in program mode - more than visible on the front panel. I-register allows indirection with branching, register and flag addressing, and other functions. Painless program editing - memory automatically shifts to make room or close gaps. Click here to see a couple of simple programs. Nice manuals. There's even a site dedicated to the 15 and to bringing it back into production!

Manufacturer Sharp	Model Elsi Mate EL-407	Mfg. Date ~1985	Accession Date ~2001	Orig. Cost	Batteries 2 1.5V button	Made in Japan
Display LCD	Programming	Digits (guards) 8		Forensic #	69!	Fractions
Stats	Non-decimal	Memory 1 (continuous)	Conversions
Comments An alarm clock plus very basic calculator.

Manufacturer Casio	Model fx-451	Mfg. Date 1985	Accession Date Feb 1986	Orig. Cost $36	Batteries none	Made in Japan
Display LCD	Programming	Digits (guards) 10+2 (1)		Forensic # 9.0000157179	69! 1.25s-1.75s depending on light	Fractions yes, can store in mem and do 4-func math
Stats 1-var	Non-decimal base 2/8/16, logic ops	Memory 1	Conversions R/P, H/HMS, metric (8)
Comments Fully solar - no battery. I also owned the predecessor to this, the fx-450. When the 451 came out, feature-itis compelled me to buy it - it had added metric conversions and four more constants! I sold my 450. In some ways though, I preferred the 450. It felt a bit more solid - the fold-out keyboard was significantly thicker and stronger. Oh well, both nice machines. One of, if not the first to include built-in physical constants (13 (9 on the 450)). The first I'm pretty sure to combine solar, constants, fractions, and logical ops (and metric conversions) in one machine, and virtually unrivalled to this day! (well, maybe not) The Engineering mode keys are neat. Using them, you can bounce the decimal around in jumps of 3, either way, in case you prefer microfarads to nanofarads for instance. A rare instance of inverse trig functions being available in a single keystroke. Apparently, the museum's example is a rarer version with a larger solar cell.

Manufacturer Majestron	Model watch	Mfg. Date	Accession Date Jan 2002	Orig. Cost	Batteries	Made in Hong Kong
Display LCD	Programming	Digits (guards)		Forensic #	69!	Fractions
Stats	Non-decimal	Memory	Conversions
Comments

Manufacturer ?	Model DC-2	Mfg. Date	Accession Date Apr 2004	Orig. Cost	Batteries 2 L1130 1.5V	Made in Taiwan
Display LCD	Programming	Digits (guards) 8		Forensic #	69!	Fractions
Stats	Non-decimal	Memory 1, volatile	Conversions
Comments Sqrt! Reminiscent of the Commodore PET, no?

Manufacturer	Model Compucard	Mfg. Date	Accession Date	Orig. Cost	Batteries 2 G10 1.5V	Made in Taiwan
Display LCD	Programming	Digits (guards) 8		Forensic #	69!	Fractions
Stats	Non-decimal	Memory 1, volatile	Conversions
Comments

Manufacturer Toshiba	Model LC-851	Mfg. Date 1988	Accession Date Jan 2002	Orig. Cost	Batteries 1 3V "LF-1/3W" (very close to a 2325, but even a 2025 works)	Made in Japan
Display LCD	Programming	Digits (guards) 8		Forensic #	69!	Fractions
Stats	Non-decimal	Memory 1, volatile	Conversions
Comments Noticeably slower than a modern 3V calc. Sq, sqrt.

Manufacturer	Model Mutual Group promo	Mfg. Date	Accession Date Apr. 2004	Orig. Cost	Batteries Solar	Made in
Display LCD	Programming	Digits (guards) 8		Forensic #	69!	Fractions
Stats	Non-decimal	Memory 1, volatile	Conversions
Comments Sqrt.

Manufacturer	Model matchbook	Mfg. Date	Accession Date ~1996	Orig. Cost	Batteries 1 L1131 1.5V	Made in China
Display LCD	Programming	Digits (guards) 8		Forensic #	69!	Fractions
Stats	Non-decimal	Memory 1, volatile	Conversions
Comments A great little novelty calc, I got this for free by pretending to be a smoker and filling out a questionnaire.

Manufacturer Aurex	Model SC-101	Mfg. Date ~1995	Accession Date May 2004	Orig. Cost	Batteries 2 AG13 1.5V	Made in China?
Display LCD	Programming	Digits (guards) 10/8+2 (2)		Forensic # 8.99999863704	69! 0.25s	Fractions
Stats 1-var	Non-decimal base 2/8/16, arithmetic only	Memory 1, continuous	Conversions D/R/G, R/P, H/HMS
Comments This calc has the same part number and functionality as one below, but is in a totally different case. Same story as the SC-107, but at least they changed the number for that one. Most notes for either below apply to this as well. Generic instruction booklet - no company name.

Manufacturer Steven Costenoble	Model SciCalcRPN 2.0	Mfg. Date 1996	Accession Date 2000	Orig. Cost	Batteries	Made in USA
Display	Programming	Digits (guards) 14+3 (3)		Forensic # 8.9999999998325678	69! ~0s	Fractions
Stats 1-var, P&C	Non-decimal base 2/8/16, logical, shifts, mod, selectable word size...	Memory 10, continuous	Conversions deg/rad
Comments Virtual RPN calc. User-selectable display font. Dynamic range of about 10^+/-300.

Manufacturer	Model CAL101	Mfg. Date	Accession Date 2001	Orig. Cost	Batteries 1 G10 1.5V	Made in
Display LCD	Programming	Digits (guards) 8		Forensic #	69!	Fractions
Stats	Non-decimal	Memory 1, volatile	Conversions
Comments Not made by National, but given away by them promotionally. No OFF button, it just times out. Surprising for this class of unit, a sqrt key. Cool viscous-damped display cover flips open to act as a stand.

Manufacturer Casio	Model Data Bank DC-2000/130	Mfg. Date 1997	Accession Date ~2000	Orig. Cost ~$8	Batteries 1 2032 3V	Made in China
Display LCD	Programming	Digits (guards) 8		Forensic #	69!	Fractions
Stats	Non-decimal	Memory 1, continuous	Conversions
Comments A cheap little pocket organizer. Memory is actually capacitor-backed while battery is changed. FYI, power consumption is 240µW...

Manufacturer John Brochu	Model CalcWorks 1.5.4	Mfg. Date 1999	Accession Date 1999	Orig. Cost	Batteries	Made in USA
Display	Programming	Digits (guards) 12+2 (8)		Forensic # Reads 9, actually 8.999999999999992	69! ~0s	Fractions
Stats	Non-decimal base 2/8/10/16, logical, shifts, selectable word size...	Memory 10, volatile	Conversions DRG, P/R, H/HMS(frames), ft/ft-inch, many metric
Comments Virtual calc. Switchable between RPN, simple, and algebraic. Allows all the logical ops in base 10! Has 16 physical constants - editable in case you move to a different universe (conversions also editable). Virtual "paper tape" can be saved and recalled.

Manufacturer Casio	Model CFX-9850GB plus	Mfg. Date ~1999	Accession Date Mar 2000	Orig. Cost ~$90	Batteries 4 AA, 1 2032 backup	Made in Malaysia
Display 3-colour (variable pixel) graphic LCD, 128x64	Programming BASIC-like language, 28KB	Digits (guards) 10+2 (5)		Forensic # 9.00000000733343 (0.3sec)	69! 0.25s	Fractions yes, can store in mem, do 4-func math, 1/x, x²
Stats 1-var, P&C, LR, etc, etc	Non-decimal base 2/8/16, logic ops, mixed-base calcs	Memory 28, continuous, plus many other data-types stored	Conversions D/R/G, R/P, H/HMS
Comments Is it a calculator or a computer? Yes. Computer power at calculator speed unfortunately. Very thorough set of statistical and analysis functions, including many types of graphs. Fairly good implementations of complex numbers and matrices. Editable history of course. Numerical differentiation, integration, summation. Can connect to printer, computer, or other calc. Can solve sets of equations with up to six unknowns. Find roots of 2nd & 3rd-order eqns, including complex ones. Graphing, including interactive eqn solving, multiple overlaid or separate graphs, zooming, constructing a table of values or graph a table, drawing multiple graphs and "animating" between them, statistical/probability graphs... Spreadsheet-like operations. Curve fitting (lin to 4th-order, exp, periodic...). Financial funcs. The picture shows 3 graphs and the intersection point of 2 of them. I've enhanced the LCD display in the picture, as it's pretty poor in real life.

Manufacturer Hewlett-Packard	Model HP-6S (Solar)	Mfg. Date ~2000	Accession Date Mar 2001	Orig. Cost $10 ($15 solar)	Batteries 2 LR43 (1 solar)	Made in China
Display LCD	Programming	Digits (guards) 10+2 (2)		Forensic # 8.99999863704	69! 0.25s (non-solar), 1.5s (solar)	Fractions yes, can store in mem and do 4-func math
Stats 1-var	Non-decimal base 2/8/16, logic ops	Memory 1	Conversions D/R/G, R/P, H/HMS
Comments Funny -- the two versions of this calc are both called 6S. You'd think that moniker would be reserved for the solar. This model is actually made by Chinese company Karce. I don't know if H-P had a hand in the design, or if they have simply taken it as-is and rebranded it. I guess it's their way of establishing a presence in the scientific bottom-end. Not RPN! Note that the Aurex SC-108 is also a Karce rebrand and identical in function to the H-P! The odd thing about the solar - there's no power switch! It's always on. I try to keep it well-illuminated, leaving the top of the calc sticking out of its pouch, so as to maximize battery life. The AC button kinda behaves like a power switch, doing a full reset. Continuous memory, as long as you don't hit that button! Yet, the non-solar is continuous for memory and modes. Interesting that the 2-cell non-solar is significantly faster than the 1-cell solar, though the solar does speed up in bright light. Really! Small exponent digits on solar only. The non-solar is a bit thicker and more sturdy than the solar! Its blue colour sure makes it hard to read the legends. It's also better shielded. The solar has an internal LED! I can only guess this acts as an OVP in case the 4-section solar battery puts out too much juice!

Manufacturer Hewlett-Packard	Model HP-30S	Mfg. Date ~2000	Accession Date Mar 2001	Orig. Cost ~$25	Batteries 2 LR44 1.5V	Made in China
Display LCD 2-line, upper is 11chr 5x7 dot-matrix	Programming 1 expression with up to 4 variables can be stored	Digits (guards) 10+2 (spec is 24 digits internal)		Forensic # 9, exactly! (2sec)	69! 0.5s	Fractions yes, can store in mem, do 4-func math, x²
Stats 1-var, P&C, LR	Non-decimal nope!	Memory 11, continuous	Conversions D/R/G, R/P, H/HMS, frac/dec, metric (62 incl. trivial ones like m/km and less trivial like ft/mi)
Comments Since the HP-30 laughed at the forensics test, I tried a tougher one, using 1 instead of 9: foren(1)=1.0000000005536418873860643... Seems I can get an infinite number of digits, which reinforces the theory that binary is being used instead of BCD, and I'm just drawing out conversion error. See TI below for a very similar unit. Comes with 3 different-coloured faceplates for your aesthetic enjoyment. Display has "slashes" between digits for fraction display, and thousands-separator commas above the digits. Decimal-to-fraction conversion is cool! Whoa!!! Just discovered buggy fraction behaviour: Enter 71/333 as a fraction, divide by 10, you get 10/475! Not only wrong, but unreduced!!! It's the Pentium flaw all over again. It seems though that current production has fixed this (I tried one in a store). HP support has been friendly, but has yet to supply a replacement. The museum has notified the technical press! Menu of 12 physical constants. Conversions include Imperial gallon. Finds roots of quadratic eqns. Solves (finds intersection) for pairs of linear eqns! Docs are not like the good old days. Instead of a nice book, we get two large sheets of paper, one with an operating summary, one with examples. So, just what kind of calculator is this? It's not RPN. It's not normal algebraic entry. It's a member of what seems to be an increasingly common type of machine, where you basically enter an expression as you'd write it. This is okay or even nice sometimes. They do tend to have history stacks, so you can go back and redo/edit a previous expression. But, I believe most serious users do not think in this outside-in way. It's the polar opposite of RPN after all. It also means that monadic operators (e.g., 1/x, x²) take two keystrokes, as you must press = after the operator. In fact, many operators (e.g., sqrt, trig, log) take four keystrokes to work on the display register (op, 2nd, Ans, =). Yuck.

Manufacturer Texas Instruments	Model TI-30X IIB	Mfg. Date 2001	Accession Date ~2002	Orig. Cost $20-$30	Batteries 1 2025 3V	Made in China
Display LCD 2-line, upper is 11chr 5x7 dot-matrix	Programming	Digits (guards) 10+2 (3)		Forensic # 9.000003512065 (2.5sec)	69! 0.4s	Fractions yes, can store in mem, do 4-func math, 1/x, x², even arbitrary root extraction for simple cases!
Stats 1-var, P&C, LR	Non-decimal nope!	Memory 5, continuous	Conversions D/R/G, R/P, H/HMS, frac/dec
Comments Very hard to replace battery: Remove four tiny screws, then carefully unsnap case halves. Guess they just want you to buy a new one. Has internal LED!!! Probably OVP for solar version - they forgot to leave it out... Many similarities to the HP-30 above (including the number! See the HP's closing comments as they apply to the TI too) lead one to believe they might have been designed and manufactured by the same Chinese company. What a scary thought. Display has "slashes" between digits for fraction display. Decimal-to-fraction conversion is cool! Docs are not like the good old days. Instead of a nice book, we get a few sheets of paper with an operating summary and examples. Here's a really good (bad) example of what I was talking about for the HP30: To take the square root of the current display takes five keystrokes!!! 2nd, sqrt, 2nd, Ans, = ! Double yuck. So, is this the spiritual descendant of the original TI-30? Or did they just run out of numbers...

Manufacturer ?	Model "iMac" calculator	Mfg. Date 2001-2002	Accession Date 2002	Orig. Cost	Batteries 1 2032 3V (3 AAs for radio)	Made in
Display LCD	Programming	Digits (guards) 12		Forensic #	69!	Fractions
Stats	Non-decimal	Memory 1, continuous	Conversions
Comments Calc, clock/alarm/calendar, thermometer, and FM radio!

Manufacturer ?	Model Keychain calculator	Mfg. Date 2001-2002	Accession Date 2002	Orig. Cost	Batteries 1 LR621	Made in
Display	Programming	Digits (guards)		Forensic #	69!	Fractions
Stats	Non-decimal	Memory	Conversions
Comments Sqrt!

Manufacturer Aurex	Model SC-107	Mfg. Date ~2001	Accession Date ~2001	Orig. Cost <$10	Batteries 2 L1131 1.5V	Made in China
Display LCD	Programming	Digits (guards) 10/8+2 (2)		Forensic # 8.99999863704	69! 0.25s	Fractions
Stats 1-var	Non-decimal base 2/8/16, arithmetic only	Memory 1, continuous	Conversions D/R/G, R/P, H/HMS
Comments Made by Karce. Battery compartment is actually accessible under a removable cover, but batteries are virtually impossible to remove. Still requires case disassembly, or maybe very deft work with a pointy X-Acto! Looks like the case and the battery cover were designed by different people: The case works better with thicker LR44s (they're removable), whereas the cover will only allow the thinner L1131s! Has table of physical constants stuck inside case! Same calc as SC-101 below. Has odd function (above left parenth) that exchanges display with some "internal register" - seems to hold the last result or second-last entered number. Angular mode and mem continuous, but not operating mode! Backspace key. Complex number mode! Works for basic arithmetic only though. Generic instruction booklet - no company name.

Manufacturer Aurex	Model SC-108	Mfg. Date ~2002	Accession Date ~2002	Orig. Cost <$10	Batteries 1 G10 1.5V	Made in China
Display LCD	Programming	Digits (guards) 10+2 (2)		Forensic # 8.99999863704	69! 1s	Fractions yes, can store in mem and do 4-func math
Stats 1-var	Non-decimal base 2/8/16, logic ops	Memory 1, continuous	Conversions D/R/G, R/P, H/HMS
Comments Presumably made by Karce; identical key functions to the HP-6S! PCB is amenable to solar connections. As with the non-solar 6, all mode settings are held when off. Manual hilariously claims "158 Functions"! Generic instruction booklet - no company name.

Manufacturer Aurex	Model SC-101	Mfg. Date ~2003	Accession Date 2003	Orig. Cost <$10	Batteries 2 LR44 1.5V	Made in China
Display LCD	Programming	Digits (guards) 10/8+2 (2)		Forensic # 8.99999863704	69! 0.3s	Fractions
Stats 1-var	Non-decimal base 2/8/16, arithmetic only	Memory 1, continuous	Conversions D/R/G, R/P, H/HMS
Comments Karce? No expense spared: Six screws holding case together. Same calc as SC-107. Has odd function (above left parenth) that exchanges display with some "internal register" - seems to hold the last result or second-last entered number. Angular mode and mem continuous, but not operating mode! Backspace key. Complex number mode! Works for basic arithmetic only though. Manual hilariously claims "128 Functions"! Generic instruction booklet - no company name. Same model number and functions as previous SC-101, just a different case!

Manufacturer Sharp	Model EL-546V (or VB)	Mfg. Date 2003-4	Accession Date Apr. 2004	Orig. Cost $25	Batteries 2 LR44/A76 1.5V & Solar	Made in China
Display LCD 2-line, upper is 12chr 5x5 dot-matrix	Programming 1 expression (not storable) with up to 7 variables can be entered and repeatedly evaluated	Digits (guards) 10+2 (2)		Forensic # 8.99998762105 (0.8sec)	69! 0.1s or less	Fractions yes, can store in mem and do 4-func math
Stats 1-var, P&C, LR & 5 non-linear types	Non-decimal base 2/8/16, logic ops	Memory 7, continuous	Conversions D/R/G, R/P, H/HMS, frac/dec, Metric (22)
Comments "327 Functions"! Table of physical constants (40) and metric conversions in cover to look up the 2-digit code used to access that function or number. Has Imperial gallon and ounce conversions, not just damn US ones! See applicable HP-30S notes re equation-entry type calcs. However, operation for monadic prefix operators (like sqrt) on the current result is improved: one only needs to press (e.g.) sqrt, then equals. The Ans key is implied and automatically inserted. Hyperbolics and R/P conversions on the "math" menu key. Has an annoying attribute: When entering an expression, operators are displayed on the upper line, but numbers enter onto the lower line. When a number entry is done, it gets "pasted" into the upper line. The history stack is volatile, which is a real pain when combined with the auto-off "feature"! Can solve sets of equations with up to three unknowns. Complex numbers can be entered normally or in polar form - basic math, 1/x, x² only. Numerical integration and differentiation.

Manufacturer Casio	Model fx-991MS	Mfg. Date 2003	Accession Date Apr. 2004	Orig. Cost $23	Batteries 1 LR44 1.5V & Solar	Made in China
Display LCD 2-line, upper is 12chr 5x6 dot-matrix	Programming 1 expression (not storable) with up to 8 variables can be entered and repeatedly evaluated, or, one can repeatedly execute statements in the history stack (also not stored).	Digits (guards) 10+2 (2)		Forensic # 8.99999863704 (1sec)	69! 0.25s	Fractions yes, can store in mem, do 4-func math, 1/x, x², x³, fractions in both parts of an exponent!, even arbitrary root extraction for simple cases!
Stats 1-var, P&C, LR & 5 non-linear types, probability distributions	Non-decimal base 2/8/10/16, logic ops, mixed-base calcs	Memory 9, continuous	Conversions D/R/G, R/P, H/HMS, frac/dec, Metric (20)
Comments Table of physical constants (40) and metric conversions in cover to look up the 2-digit code used to access that function or number. Has Imperial gallon (but not ounce) conversion, not just damn US one! Case even tougher to open than TI-30! See applicable HP-30S notes re equation-entry type calcs. However, operation for monadic prefix operators (like sqrt) on the current result is improved: one only needs to press (e.g.) sqrt, then equals. The Ans key is implied and automatically inserted. Switchable comma/period separators like the HP-15! The history stack is volatile, which is a real pain when combined with the auto-off "feature"! Can enter and display numbers using metric prefixes, from femto to Tera!!! Engineering mode keys bounce the decimal around just like the fx-451. Finds real & complex roots up to third-order. Solves eqns for any variable. Can solve sets of equations with up to three unknowns. Complex numbers can be entered normally or in polar form - basic math, 1/x, x², x³ only. Numerical integration and differentiation. Good range of matrix (& vector) operations (up to 3x3). Finally, an equation-type calc that puts "Ans" on a direct key instead of a "shifted" one! What are the other mfrs thinking?!?

Manufacturer Aurex	Model SC-6103	Mfg. Date ~2003	Accession Date June 2004	Orig. Cost $15	Batteries 1 2025 3V	Made in China
Display LCD 2-line, upper is 12chr 5x7 dot-matrix	Programming 1 line with up to 9 variables can be stored	Digits (guards) 10+2 (3)		Forensic # 9.000002051244 (1.4sec)	69! 0.75s	Fractions yes, can store in mem, do 4-func math, 1/x, x², x³
Stats 1-var, P&C, LR & 5 non-linear types	Non-decimal base 2/8/10/16, logic ops, mixed-base calcs	Memory 9, continuous	Conversions D/R/G, R/P, H/HMS, frac/dec
Comments Made by ?. Surprisingly, has a 32kHz watch crystal inside, yet no time functions. Remarkably similar to Casio fx-100MS, and also pretty close to 991 above, yet the forensic result does not match any other calc in the forensic master-list. See applicable HP-30S notes re equation-entry type calcs. However, operation for monadic prefix operators (like sqrt) on the current result is improved: one only needs to press (e.g.) sqrt, then equals. The Ans key is implied and automatically inserted. The unit can maintain an enormous history stack; I stopped counting at 100! Instructions say 750 characters. And, it is non-volatile! Engineering mode keys bounce the decimal around like the fx-451. Almost programmable!: Multiple expressions can be entered on one line, with the calc stopping to display each result, or simply continuing to the next expression. This line can also be stored in a dedicated memory. Surprisingly good instruction "sheet" even has "Aurex" name on it! Decimal to fraction only works on non-repeating decimals unless... the display is the result of a calculation. E.g., the result of 1/3 will convert to a fraction, but type in .333333... and you're out of luck! Finds real & complex roots up to third-order. Can solve sets of equations with up to three unknowns. Complex numbers - basic math, 1/x, x², x³, sqrt only. Not bad! Numerical integration. Another equation-type calc that puts "Ans" on a direct key instead of a "shifted" one! Congratulations. So, isn't this interesting: A cheap generic calc that is in many ways superior to the Casio and Sharp above. Hell, it's interesting that such a sophisticated machine is even available as a generic!

Manufacturer Busrel (yeah, right)	Model "BRB-2001"	Mfg. Date ~2003	Accession Date June 2004	Orig. Cost	Batteries 2 L1130 1.5V	Made in China?
Display LCD	Programming	Digits (guards) 8		Forensic #	69!	Fractions
Stats	Non-decimal	Memory 1, volatile	Conversions
Comments Faux cell-phone. Sqrt. Key beep.

Manufacturer "Merangue"	Model SC516BL	Mfg. Date ~2004	Accession Date July 2004	Orig. Cost $8	Batteries 1 2025 3V	Made in China
Display LCD 2-line, upper is 12chr 5x7 dot-matrix	Programming Multiple user formulas can be stored (up to ~170 chrs total, non-volatile); 38 pre-programmed formulas.	Digits (guards) 10+2 (14!)		Forensic # 9 (exactly!) (2.4sec)	69! 0.4s	Fractions Can do 4-func math, but that's it. Uses a dedicated mode, memories unavailable.
Stats 1-var, P&C	Non-decimal base 2/8/10/16, logic ops, memories unavailable	Memory 28, continuous	Conversions D/R/G, R/P, H/HMS, fraction TO decimal
Comments Made by ?. Yet another take on the 2-line scientific calc design. PCB has 2001 design date. See applicable HP-30S notes re equation-entry type calcs. Operation for monadic prefix operators (like sqrt) on the current result is NOT improved: one needs to press SHIFT, ANS, EXE. Unusually for this type, the unit maintains NO history stack (well, one line!). Has engineering mode. Although the design is nice, uses soft rubber keys, and is sleekly PDA-like, I don't like the key layout too much. Shift, On/Clr and Exp are in weird places, and it's too easy to turn the machine off. The pre-programmed formulas range in complexity from Ohm's law, πr^2 and E=mc^2 to the cosine theorem and sums of progressions. They can be executed using values already in the memories or prompt for each. There are ten physical constants available from the keyboard. Can handle 11-digit octal numbers and 32-bit binary! "Block" scrolls between fields. Foren(1)=1.00000000055375750875202 - very close to the HP-30S but not identical.

Notes:

LR44 aka A76 aka AG13
L1131 aka G10
LR43, LR621, 2025, 2032, 2325, 2335

Watch out for Chinese button cells. The quality of most over the last few years has been abysmal. I've seen store displays of cheap trinkets where over half the batteries were corroded!

E-mail me