Appendix C: Service and Maintenance88
The procedure for using the battery charger is as follows:
1. Make sure the line-voltage select switch on the battery charger is set to the proper voltage. The two line voltage ranges are 86 to 127 volts and 172 to 254 volts.
Your HP-65 may be damaged if it is connected to the charger when the charger is not set for the correct line voltage.
2. Turn the HP-65 power switch to OFF.
3. Insert the battery charger plug into the rear connector of the HP-65 and insert the power plug into a live power outlet.
4. Slide the power switch to ON. If the W/PRGMRUN switch is set to RUN, you should see a display of 0.00.
5. Slide the power switch to OFF if you don’t want to use the calculator while it is charging.
6. At the end of the charging period, you may continue to use your HP-65 with ac power or proceed to the next step for battery-only operation.
7. With the power switch turned OFF, disconnect the battery charger from both the power receptacle and the HP-65.
The use of a charger other than the HP 82002A Battery Charger supplied with the calculator may result in dame to your calculator.

Battery Operation

Use only the HP 82001A Battery Pack. A fully charged battery pack provides approximately three hours of continuous operation. By turning the power off when the calculator is not in use, the HP-65’s battery pack should easily last throughout a normal working day.