Dell Latitude 5285 - Tablet LED Diagnostics; Real Time Clock (RTC) Reset

Tablet LED
This section details the diagnostic features of the battery LED in a tablet.
Diagnostic LED
Tablets rely on the Battery LED light blinking amber/white pattern to determine failures listed in the following table:
NOTE:
● The blinking patterns will consist of 2 sets of numbers being represented by (First Group: Amber blinks, Second Group:
White blinks)
● First Group: The LED blinks 1 to 9 times followed by a brief pause with LED off at the interval of 1.5 seconds. (This is in
Amber color)
● Second Group: The LED blinks 1 to 9 times, followed by a longer pause before the next cycle starts again at the interval
of 1.5 seconds. (This is in White color)
● Example: No Memory detected (2,3), Battery LED blinks two times of amber color followed by a pause, and then blinks
three times of white color. The Battery LED will pause for 3 seconds before the next cycle repeat itself again
The following table depicts the amber and white blinking patterns with possible troubleshooting resolution:
Table 2. LED pattern
Blinking pattern Problem Description Suggested Resolution
2,1 processor processor failure
2,2 system board, BIOS ROM system board, covers BIOS corruption or ROM
error
2,3 memory no memory/no RAM detected
2,4 memory memory failure/RAM failure
2,5 memory invalid memory installed
2,6 system board; chipset system board/ chipset error
2,7 display display failure
3,1 RTC power failure coin-cell battery failure
3,2 PCI/Video PCI/Video card/chip failure
3,3 BIOS recovery 1 recovery image not found
3,4 BIOS recovery 2 recovery image found but invalid
Real Time Clock reset
The Real Time Clock (RTC) reset function allows you or the service technician to recover the recently launched model Dell
Latitude and Precision systems from select No POST/No Boot/No Power situations. You can initiate the RTC reset on the
system from a power off state only if it is connected to AC power. Press and hold the power button for 25 seconds. The system
RTC reset occurs after you release the power button.
NOTE:
If AC power is disconnected from the system during the process or the power button is held longer than 40
seconds, the RTC reset process is aborted.
The RTC reset will reset the BIOS to Defaults, un-provision Intel vPro and reset the system date and time. The following items
are unaffected by the RTC reset:
● Service Tag
● Asset Tag
● Ownership Tag
● Admin Password
Troubleshooting
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