New Stuff
Author
Links
Guest book
Web-log
Bric-a-brac
Calculators
Components
Ephemera
Events
Glossary
History
Hit or Miss
Radios
Transport
Valves
Wanted
Metal Puzzles
Clocks
Calculators: Handheld: Royal 81M (aka UA127)
|
|
|
Size (approx): |
62mm x 192mm x 22mm (w,h,d) Weight 68g excluding batteries |
| Power: | 4.5V, 3 x AAA size batteries. It does not accept an adapter. | ||
| Case: | Small two-piece black matt plastic case with the top area dominated by a wrap around brushed aluminium panel. This is printed black with the brand and model number and sits flush in its own recessed area. The small green plastic display filter is inset and gently tilted. The small keys are bouncy with a soft metallic click. The on/off switch has embossed labels and a red dot to indicate the on position. | ||
| Display: |
8 digit green VFD, with a
ninth digit for minus, error and memory indication.
|
||
| Features: | 4 function calculator with percentages and four function memory | ||
| Age: | 1976 | ||
| Manufacturer: | Royal Typewriter Company, Hartford, Connecticut, USA, serial number 72.561.398 | ||
| Comments: | Tiny but solid palm-sized calculator that resembles similar models by Adler and Triumph. They also issued a similar 80K model (so I presume if was K for Constant and M for Memory). To make it so small the display is rather narrow, so much so that the minus sign almost looks like a dot. The logic is quite good with full recovery and only let down by the negative zero bugs. The original case is soft black plastic stitched in a very square edged way. It has an open top and half-moon cut-outs wither side. |
| Components: | 1 x cpu: Mitsubishi M58618-84P
6223, 24 pin DIL, 0.6" width 1 x 9 digit VFD single tube round face, 1 x transistor 3 x diodes 4 x capacitors 2 x resistor arrays 4 x resistors 1 x transformer: 13A |
| Boards: | The main cpu board (P-0024-0 EBANA 81M) sits on top of the keyboard assembly (GICO 52.11.29) (date code 29th November 1976) and the whole unit sits lose in the case. The two are joined together by 13 stiff long copper wires. |
| Construction: | Remove the single screw from the back. Then gently pop the lugs on one side by pressing in the rear section edge. Eventually the rear will lift off. |
| Logic comments: | The (C/CI) key is used to clear last entry of a number and a second press clears the whole calculator. |
| Overflow on number input is suppressed inputting a ninth digit is ignored | |
| Negative numbers are shown by a "-" in the far left (ninth) digit thereby allowing full eight digit negative numbers | |
| An overflow shows the result with a “C” (or “E” if negative) in the far left (ninth) digit and is recoverable using (C/CI) | |
| Divide by zero results in zero and a "C” in the far left (ninth) digit and is recoverable using (C/CI) | |
| There is automatic constant on all four functions | |
| The memory system is a two key affair: (M)(+) to add to memory, (M)(-) to subtract. (M)(=) to recall and (M)(C/CI) to clear | |
| Memory store is indicated by the far left (ninth) digit's decimal point | |
| Overflow in memory stores the result | |
| It suffers the negative zero bug: key in (1)(-)(2)(=) to give "-1" the (+)(1)(=) will give "-0" | |
| It also suffers the divide to negative zero bug key in: (1)(1)(=)(/)(1)(0)(=)(=)(=) etc to eventually give "-0" |
