Characters which cannot be displayed using keyboard input can be displayed using 
the CHR$ function. 
1.7  Power Supply 
This unit is equipped with a main power supply (four AA Alkaline batteries) and a 
backup power supply (one CR2032 lithium battery). Batteries should be replaced 
whenever the display remains dim, even after contrast adjustment. Batteries should 
also be replaced once every two years regardless of how much the unit has been 
used. 
 
Battery Replacement 
1) Switch the power of the unit OFF and 
remove the rear panel of the unit after 
removing the three screws holding it in 
place. 
 
2) To replace the four batteries of the main 
power supply, position the internal switch to 
the right, slide the cover of the battery 
compartment and replace the four AA 
batteries. 
Put back the internal switch in its central 
position 
 
3) To replace the memory backup battery, 
position the internal switch to the left, slide 
the cover of the battery compartment and 
replace the CR2032 battery. 
Put back the internal switch in its central 
position 
 
4) Replace the rear panel on the unit and three screws to hold it in place. 
 
1.8  Auto Power Off 
The power of the unit is automatically switched OFF approximately 6 minutes after 
the last key operation (except during program execution), or the last input for an 
INPUT statement or PRINT statement. Power can be resumed by either switching 
the power switch OFF and then ON again, or by pressing the BRK key. 
Program and data contents are retained even when power is switched OFF, but 
settings such as the number of digits or the mode (i.e. BASIC mode) are cancelled. 
1.9  SYSTEM* Self Test Function 
The unit has a powerful built-in self-test function you can address by entering the 
following command: 
.S   Y   S   T   E   M   *  . .