Once a Panasonic projector's lamp timer reaches the lifetime limit of its lamp, it automatically puts the projector in standby mode after 10 minutes of use. Different projectors have different maximum lamp lifetimes, but most are between 2,000 and 3,000 hours. The lamp timer doesn't detect when you've installed a fresh bulb, so you have to manually reset it when you're replacing the bulb.
Turn the projector on and press the "Menu" button, either on the projector's remote or the projector itself.
Select "Option" from the menu and go to "Lamp Runtime" in that subcategory. This screen displays how many hours the projector's lamp has logged.
Press and hold the "Enter" button for three seconds to bring up the "Reset Lamp Runtime" confirmation screen.
Select "OK" on the confirmation screen, then turn off the projector to reset the lamp runtime counter.
Go back to the "Lamp Runtime" option screen to confirm the lamp timer has been reset to zero.