Keystone SC 650
The Keystone SC 650 is an arithmetic calculator with 8 digits precision and algebraic logic. It has 7 functions, 20 keys, and a gas discharge display. The power source is 2xAA.
Facts at a glance:
If you have a Keystone SC 650 that is no longer working, you can first try replacing the 2xAA 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: