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: Bohn Omnitrex
|
|
Size (approx): | 68mm x
127mm x 17-22mm (w,h,d) Weight 272g excluding batteries |
|
Power: |
7.5V DC, 5 x AA size batteries. Accepts an adapter (undefined but 4mm plug, centre positive, 1.5 watts) through a socket on the right side at the top. | |
| Case: | Two piece dark grey and cream (originally white?) case with a matching dark grey front panel. Wedge shaped and just about fits in the hand. Large, tilted inset green display filter does a good job. Printed company and model number has survived well. Typewriter-style keys have short travel and positive click. | |
| Display: | 8 digit green VFD with a ninth digit for negative and error signs. | |
| Features: | Standard four functions with percentages and change sign. Switched financial input mode. | |
| Age: | 1973 | |
| Manufacturer: | Bohn Rex Rotary, service centres at 475 S. Dean St., Englewood, NJ 07631 and 121 S. Palm St., Alhambra Cal 91801. Made in Taiwan. Serial No. 3726731-C. | |
|
Comments:
|
Advanced early compact USA calculator which retailed for $100. Early display is still bright and clean. Logic sound but odd mode of operation - help I need a manual! Lovely. |
| Components: | 1 x cpu: Rockwell A1032PD 15332
7339 (date code week 39 of 1973) 42 pin staggered DIL 9 x 1 digit glass tube VFD displays: ISE DG8F GJC Japan 4 x transistors 8 x diodes 7 x capacitors 0 x resistor arrays 18 x resistors 1 x transformer |
| Boards: | The keyboard (Ref 1KS157 45335 1st issue) unit is removed via two screws into their supporting posts. It is joined to the main cpu board by 9 flexible wires with four additional wires going to the switches. |
| Construction: | Remove the four screws form the back and the front will gently ease off with a little squeeze. The whole assembly is attached to the back. Remove the keyboard unit via the two screws. |
| Logic comments: | The (C) key operates as a cancel entry function on the first press and all clear on the second |
| Input overflow is suppressed, inputting a ninth digit is ignored | |
| Negative numbers are shown with a "-" in the ninth (far right) digit thereby allowing eight digit negative numbers. | |
| There is automatic constant on multiply and divide but implied constant on plus and minus by repetitive pressing the operator keys. | |
| Divide by zero shows a "C" in the ninth (far left) digit and is recoverable using (C) | |
| Overflow displays the result and "C" (or "E" for negative overflows) in the ninth (far left) digit and is recoverable using (C) | |
| The change sign key can be used in mid entry of a number | |
| Slightly odd semi reverse polish logic - help I need a manual | |
| There is a switch to change the decimal point notation from floating to "$.00". In the latter mode inputting (4)(5)(6) will result in the number 4.56. |
