Sony PCG-GRX500K - Manual (Page 79)

Connecting an External Display
79
Use the Fn+F7 key combination to select the display you want. See “Selecting
the Display Mode” for more information.
To Press Result
Switch to an
external display Fn+F7 Toggles between the LCD, the external display
connected to the Monitor port, or both the LCD
and external display.
✍
(On selected models) Connect the external display to the notebook or port replicator
before you turn on the unit, otherwise the Fn+F7 key combination will not work.
Only LCD LCD and external display
Only external display