If the HP 39gs does not turn on follow the steps below until the calculator turns on. You may find that the calculator turns on before you have completed the procedure. If the calculator still does not turn on, please contact Customer Support for further information.
1.Press and hold the 
key for 10 seconds.
2.Press and hold the 
key and the third menu key simultaneously. Release the third menu key, then
release the 
key.
3.Press and hold the 
key, the first menu key, and the sixth menu key simultaneously. Release the sixth menu key, then release the first menu key, and then
release the 
key.
4.Locate the small hole in the back of the calculator. Insert the end of a straightened metal paper clip into the hole as far as it will go. Hold it there for 1
second, then remove it. Press the 
key.
5.Remove the batteries (see “Batteries” on page
press and hold the 
key for 10 seconds, and
then put the batteries back in. Press the 
key.
Operating temperature: 0° to 45°C (32° to 113°F).
Storage temperature:
Operating and storage humidity: 90% relative humidity at 40°C (104°F) maximum. Avoid getting the calculator wet.
Battery operates at 6.0V dc, 80mA maximum.
BatteriesThe calculator uses 4 AAA(LR03) batteries as main power and a CR2032 lithium battery for memory backup.
Before using the calculator, please install the batteries according to the following procedure.