Royal 91K (UA122)
The Royal 91K is an arithmetic calculator with 8 digits precision and algebraic logic. It has 6 functions, 24 keys, and a VFD (vacuum fluorescent) display. The power source is 4xAAA.
Facts at a glance:
If you have a Royal 91K that is no longer working, you can first try replacing the 4xAAA batteries. If that doesn't solve the problem, then you can consider replacing the calculator with a modern equivalent. We suggest the following current models as possible replacements: