Collection Item |
 |
Casio Root 121-A
 |
| Brand: | Casio. |
| Model: | Root 121-A. |
| Origin: | Japan. |
| Introduction: | 1971. |
| Type: | Basic compact but heavy desktop calculator with Nixie tubes display. |
| Functions: | 4-Basic function, Square root, grand total (memory with limited functionality, see below), no constant. |
| Display: | 12 Nixie tubes. |
| Keyboard: | 19 reed-switch keys, On/Off switch. |
| Main chips: | Nec D174B, uPD357D, uPD173D and other chips from Nec and Toshiba. I don't see any date code! |
| Logic comments: | Pseudo RPN notation, very used at the beginning of the 70s, for example: To compute 2+5 you must type 2 =+ 5 =+. To compute 5-3 you must type 5 =+ 3 =-. This calculator does not has the -0 error like many others of that time, but has the pseudo fixed decimal bug. For example if you type 1.25 =+ 3.75 =+ you will read 5.00, with 2 inneccesary zeroes. Square roots are always presented with a heading 0, for example Square(2) gives 01,4142135... Grand total always accumulates multiply and divide results, you will see this grand total pressing T and clear it with AC. |
| Remarks: | Robust but compact casing with top-quality plastics and other materials, operates with AC power, no batteries support. |
| Size: | 8.07 x 7.09 x 2.56 in, 205 x 180 x 65 mm. |
| Condition: | (9.5/10) Excellent, no marks on casing, full working. |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |