APF MARK 51 (Scientific Calculator)
The APF MARK 51 is a scientific calculator with 8 digits precision and algebraic logic. It has 17 functions, 19 keys, and a VFD (vacuum fluorescent) display. The power source is PP3 9V battery.
Facts at a glance:
| Feature | Value |
|---|---|
| Type | Scientific |
| Functions | 17 |
| Keys | 19 |
| Precision | 8 |
| Logic | Algebraic |
| Display type | VFD |
| Length | 140mm |
| Width | 76mm |
| Power Source | PP3 9V battery |
| Year introduced | 1975 |
| Year discontinued | 1975 |
Replacements:
If you have an APF MARK 51 that is no longer working, you can first try replacing the PP3 9V battery. If that doesn't solve the problem, then you can consider replacing the calculator with a modern equivalent.
We suggest the following current model as a replacement: