Diagnosis
The lamp timer has reached its set limit. The PX701-4K tracks lamp usage. The blinking red light indicates the lamp hours counter has hit the threshold, not that the lamp has instantly failed.
How to Fix It
To reset the lamp timer, you must access the service menu. With the projector on, press and hold the 'Exit' button on the remote for 5 seconds. This opens the service menu. Navigate to 'Lamp Reset' or similar using arrow keys. Select 'Reset' and confirm. Exit the menu. The warning light should clear.
If That Didn't Work
If the service menu method does not work or the light returns immediately, the internal optical sensor may be detecting low lamp luminance, indicating true end-of-life. The lamp is a Philips 230W UHP model. Prepare to replace it.
Heads Up
Resetting the timer on a severely degraded lamp can lead to sudden failure or poor brightness. Monitor the 'Lamp Hours' in the standard menu (Settings > System Setup > Information). If hours are above 4000, replacement is recommended regardless of the reset.