When the RAM card runs down, the system will display a message, "RAM CARD BATTERY LOW". When you see this message, you should change the RAM card battery as soon as possible. To avoid the danger of not having a battery when you need it, set an alarm to sound 12 months from the last battery change.
The RAM card memory depends on a constant supply of power. When it is not in the HP 95LX RAM card slot or the HP 95LX is turned OFF, then the RAM card is using its own battery. Only when the HP 95LX is ON, can the RAM card draw power from the AA batteries in the HP 95LX. So, to change the battery in the RAM card with out losing memory, it must be in the RAM card slot and the HP 95LX must be ON. Make sure that the HP 95LX does not time out and turn off while you are changing the battery by pressing an occasional key or by plugging in the AC power supply. The battery is accessible while the RAM card is in the card slot. There is a battery door that can be pulled open using your thumb nail. If the door doesn't open easily, you may need to switch the door lock to the open position. See the diagrams in the User's Guide on pages 1-9 and 1-10.