Sony VGC-RB50 User Guide (primary user manual) User Manual page 17

the same type and manufacture of battery. Using incompatible batteries or mixing used/new batteries can damage
the keyboard.
Inserting batteries into the wireless keyboard
If your wireless keyboard does not operate properly, the batteries may need to be replaced. When your wireless
keyboard is not being used for extended periods of time, remove the batteries to avoid possible damage from battery
leakage.
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