Appendix F: Battery, Warranty, and Service Information 197
For a calculator that does not respond to keystrokes:
1. Insert a thin, pointed object all the way into the reset hole near the battery
compartment and then remove it.
1. The display will show Pr Error. Pressing any key will clear this message
from the display.
2. If the calculator still does not respond to keystrokes, remove and re-insert 
the battery. Make sure that the battery is properly positioned in the battery 
compartment.
3. If the calculator does not turn on, install a fresh battery. If there is still no 
response, the calculator requires service.
For a calculator that does respond to keystrokes:
1. With the calculator off, hold down the ; key and press §.
2. Release the ; key, then release the § key. This initiates a complete test 
of the calculator’s electronic circuitry. If everything is working correctly, 
within about 15 seconds (during which the word running flashes) the 
display should show –8,8,8,8,8,8,8,8,8,8, and all of the status indicators 
should turn on.
1
 If the display shows Error 9, goes blank, or otherwise 
does not show the proper result, the calculator requires service.
2
1.
The status indicators turned on at the end of this test include some that normally are not 
displayed on the 
HP 12C Platinum.
2.
If the calculator displays Error 9 as a result of the ;/§ test or the ;/+ test but you 
wish to continue using your calculator, you should reset Continuous Memory as described on 
page 70.