The Casio fx-991ES is a scientific calculator with 8 digits precision and formula input logic. It has 403 functions, 50 keys, and an LCD (liquid crystal) display. The power source is Solar. The calculator was manufactured in China. Note: Functionally the same as fx-570ES with solar power
The MT-800 seems to have been indeed the first ROM-Pack keyboard, because its behaviour has various glitches and is less elegant than later such instruments (e.g. Casio PT-80 and PT-82). These smaller instruments indicate e.g. With a walking light on the LED row above the keys that the user shall select a song number from the cartridge, and a. Home Keyboards ⇝ Casio ⇝ Casio Casiotone MT-68. The MT-68 is powered NEC D930G and D931G chips. It can be considered an upgraded version of the Casio MT-100. It is also available with a dark chassis as the MT-65. Year Released: 1983. Keyboard: 49 mini keys. ROM: 20 sounds, 12 rhythms. Effects: vibrato, delayed vibrato.
Facts at a glance:
| Feature | Value |
|---|---|
| Type | Scientific |
| Functions | 403 |
| Keys | 50 |
| Precision | 8 |
| Logic | Formula |
| Display type | LCD |
| Length | 161mm |
| Width | 80mm |
| Thickness | 12mm |
| Weight | 105g |
| Power Source | Solar |
| Country | China |
| Year introduced | 2005 |
User Manual
You can download the Casio fx-991ES manual from this external link.
Diagnostics
80s Casio Keyboard
Note that diagnostic tests generally delete any data on the calculator. Be sure to back up any important information held in the calculator before running these tests.
While holding SHIFT and 7 keys (or just SHIFT key for early models) press the ON key. Pressing the SHIFT key shows 5 display test patterns in turn, followed by the ROM version. Press AC to get the contrast test screen, and press AC again to get to the keypad test - the numbers then increase as each key is pressed in the correct order (omitting the ON key which exits test mode).
Casio Keyboard Songs
Replacements:
If you have a Casio fx-991ES that is no longer working, you can consider replacing the calculator with a modern equivalent. We suggest the following current model as a replacement:
Casio 80s Keyboard Simulator Software
See other calculators by Casio