Dell Latitude 3540, Service Manual

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• Computer is running on battery and the battery has more than 5 percent charge.
• Computer is in sleep state, hibernation, or turned off.
The power and battery-status light blinks amber along with beep codes indicating failures.
For example, the power and battery-status light blinks amber two times followed by a pause, and then blinks white three times followed by
a pause. This 2,3 pattern continues until the computer is turned off indicating no memory or RAM is detected.
The following table shows different power and battery-status light patterns and associated problems.
Table 3. LED codes
Diagnostic light codes Problem description
2,1 Processor failure
2,2 System board: BIOS or ROM (Read-Only Memory) failure
2,3 No memory or RAM (Random-Access Memory) detected
2,4 Memory or RAM (Random-Access Memory) failure
2,5 Invalid memory installed
2,6 System-board or chipset error
2,7 Display failure
3,1 Coin-cell battery failure
3,2 PCI, video card/chip failure
3,3 Recovery image not found
3,4 Recovery image found but invalid
3,5 Power-rail failure
3,6 System BIOS Flash incomplete
3,7 Management Engine (ME) error
Camera status light: Indicates whether the camera is in use.
• Solid white — Camera is in use.
• Off — Camera is not in use.
Caps Lock status light: Indicates whether Caps Lock is enabled or disabled.
• Solid white — Caps Lock enabled.
• Off — Caps Lock disabled.
WiFi power cycle
About this task
If your computer is unable to access the internet due to WiFi connectivity issues a WiFi power cycle procedure may be performed. The
following procedure provides the instructions on how to conduct a WiFi power cycle:
NOTE: Some ISPs (Internet Service Providers) provide a modem/router combo device.
Steps
1 Turn off your computer.
2 Turn off the modem.
3 Turn off the wireless router.
4 Wait for 30 seconds.
5 Turn on the wireless router.
114 Troubleshooting