Texas Instruments TI-80 User Manual - Page 212

Battery Information The TI.80 uses two CR2032 lithium 3-volt batteries. When to Replace the Batteries As you use the TI.80, the battery voltage will gradually drop, and the display will dim. You can adjust the contrast to darken the display when this happens. If the display is dim and adjusting the contrast to level 9 does not make it dark enough, you should replace the batteries. Refer to pages B-3 through B-7 for instructions on how to change the batteries. Battery Precautions Follow these safety guidelines concerning batteries. ¦ Do not mix new and used batteries. ¦ Do not mix different types of batteries. ¦ Follow polarity diagrams carefully. ¦ Do not replace batteries with rechargeable batteries. ¦ Do not place non-rechargeable batteries in a battery charger. ¦ Properly dispose of used batteries immediately. Do not leave them within the reach of small children. ¦ Do not incinerate used batteries. Retaining Stored Data Caution: The TI-80 retains stored data when you are changing batteries only if you: ¦ Do not remove both batteries at the same time. (At least one battery must be installed at all times in order to retain memory.) ¦ Turn the unit off and do not turn it back on until you have changed the batteries. ¦ Do not allow the batteries to run down completely before changing them. Follow the steps on pages B-3 through B-7 when changing batteries. B-2 Service and Warranty Information