Dell OptiPlex 7470 All-in-One Service Manual

All-in-One (AIO) systems supports LCD BIST similar to any other Dell systems that have BIST test implemented. It allows the user to isolate the LCD during troubleshooting to determine which sub-system is at fault. The main difference is the lack of an integrated keyboard scan controller in the AIO. When BIST is initiated, an internal generated pattern from the LCD will be emitted for user's observation. This pattern will go by sequence through this pattern, Red- Green-Blue-White-Blue where each pattern is emitted for 2 to 3 seconds.

The following images displays the pattern of the colors on the LCD:

Standard display

Alternative display

Invoking BIST

To invoke the LCD BIST, turn on the system and press and hold the Display Built-in Self Test button plus the Power button together. Release the buttons when Red- Green-Blue-White-Blue pattern is displayed on screen.