Appendix C: Service and Maintenance87
If a battery pack is defective and within warranty, return:
1. Only the defective battery pack.
2. A completed Service Card (from the back cover of this booklet).
Send items to be returned to the address nearest you shown on the Service Card. after packaging them safely. Under normal conditions. your calculator will be repaired and shipped to you within 5 days of receipt at this address. Should other problems or questions arise regarding service, please call the applicable service telephone number on the Service Card, or call Advanced Products Division. Customer Service Department, at (408) 996-0100.

Recharging and AC Line Operation

To avoid any transient voltage from the charger, the HP-65 should be turned off before plugging it in. It can be turned on again after the charger is plugged into the power outlet and used during the charging cycle.
A discharged battery will be fully charged after being connected to the charger for a period of 14 hours; overnight charging is recommended. Shorter charge periods will reduce battery operating time.
If desired, the HP-65 can be operated continuously from the ac line. The battery pack is in no danger of becoming overcharged. Since you cannot operate the card reader/writer without a charged battery, even with the charger plugged in, the battery should not be removed while running from the ac line. If a battery is fully discharged, it must be charged for at least 5 minutes before a card can be read or written. If the decimal points light during card feed and then go out, your battery needs recharging.
Running the HP-65 from the ac line with the battery pack removed may result in damage to your calculator.