ON/+ sequence will run a loop test. You don't want this one.
Self test is as follows :
- turn your calculator OFF (press the ON button, make sure the screen clears)
- press the X key (multiply key) AND DO NOT RELEASE IT
- press the ON key and RELEASE IT
- NOW release the X key
The calculator should show a flashing "running" message for 15 seconds, then finish up with a screen where all segments are litten up. This means that the self-test is successful.
Now you want to test the keyboard.
- turn your calculator OFF (press the ON button, make sure the screen clears)
- press the ./. (divide key) AND DO NOT RELEASE IT
- press the ON key and RELEASE IT
- NOW release the ./. divide key
- you should see strange characters
- begin pressing the top right key (square root key), then press the next key to the right (e^x), then next (key (10^x), till you reach the divide key. All key should show a different weird display
- do gain the sequence starting with SST, then again starting with R/S, then again with ON. NOTE that the ENTER key needs to be pressed twice, once for the 3rd and once for the 4th column
- Once you've reached the + ke, you should read 15 at the middle of the display, evidence that your keyboard passes the test.
There is the same sequence as the ON/X with ON/-, this will reset your calculator. All programs and registers will be lost, but your indicator will clear. Quite hard ball method.
Finally, the ON/. sequence will toggle between european and US number format (point/comma decimal point, and comma/point '000 separators)