Dell Inspiron 7590 2in1, Service Manual

Page: 102 / 106

Table 19. Functions
M-Bist L-Bist
Purpose Evaluates the health condition of the
system board. Checks if the system board is supplying
power to the LCD by performing an LCD
Power Rail test.
Trigger Press the <M> key and power button Integrated into the single LED error
code diagnostics. Automatically initiated
during POST
Indicator of fault Battery LED light with Solid Amber Battery LED error code of [2,8] blinks
Amber x2, then pause, then blinks White
x8
Repair instruction Indicates a problem with the system
board. Indicates a problem with the system
board.
System board built-in self-test (M-BIST)
1. Press and hold both the M key and the power button to initiate M-BIST.
2. The battery-status light illuminates in amber when there is a failure with the system board.
3. Replace the system board to fix the issue.
NOTE: The battery status LED will not illuminate if there is no failure present with the system board. If further
troubleshooting is required, proceed with the applicable Guided Resolution for No Power/No POST, etc.
Display panel power rail built-in self-test (L-BIST)
L-BIST (LCD Power Rail Test) is an enhancement to the single LED error code diagnostics and is automatically initiated
during POST . L-BIST isolates if the LCD is receiving power from the system board. L-BIST checks if the system board is
supplying power to the LCD by performing an LCD Power Rail test. If there is no power going to the LCD, the battery status
LED flashes a
[2,8] LED error code.
102 Troubleshooting