Elektronika MK-61
  The Elektronika MK-61 is a programmable calculator with 8 digits precision and RPN (reverse polish notation) logic. It has 30 keys, and a VFD (vacuum fluorescent) display. The power source is 3xAA batteries.
Facts at a glance:
| Feature | Value | 
|---|---|
| Type | Programmable | 
| Keys | 30 | 
| Precision | 8 | 
| Logic | RPN | 
| Display type | VFD | 
| Length | 165mm | 
| Width | 80mm | 
| Thickness | 38mm | 
| Power Consumption | 0.600000W | 
| Power Source | 3xAA batteries | 
| Year introduced | 1983 | 
| Year discontinued | 1993 | 
Replacements:
If you have an Elektronika MK-61 that is no longer working, you can first try replacing the 3xAA batteries. 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: