The Unimark 813T is an arithmetic calculator with 8 digits precision and algebraic logic. It has 7 functions, 22 keys, and a VFD (vacuum fluorescent) display. The power source is 4xAA. The calculator was manufactured in Japan.
Facts at a glance:
If you have a Unimark 813T that is no longer working, you can first try replacing the 4xAA 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: