Blinking Lights - HP EliteBook 850 G4 Maintenance And Service Manual

The sections below are intended for authorized service providers/technicians.
Tips and tricks

Blinking lights

Symptoms
Lights blink on keyboard
lock/num lock
Note
108 Chapter 8 Troubleshooting guide
5.
Verify display
●
●
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
Swipe a metal piece (screwdriver) over wireless/mute buttons to act as if closing lid to force
video output to external display device. See the "External component identification –
Display" section for location of the magnetic sensor.
Possible causes
caps Blinking lights on startup usually indicate a problem with basic functionality of a critical
keys component (processor, BIOS, graphics cards, memory, etc.) due to loose connection,
defective parts, or recently added parts.
Troubleshooting steps
1.
2.
3.
Since the display may not be functional, lights are used to indicate an error.
If external video is OK, update BIOS, software, and drivers
on page 87) and perform soft reset
needed. Go to next step to verify display.
When booting to Windows, determine whether image appears on display screen (via
Windows Screen Solutions or Windows logo
If there is video on display, disconnect external display device, open the computer lid
and restart.
Verify Power Good lights are on to be sure that system board power is functional.
Reseat display cable connection on system board.
Reseat display cable connection on display panel side.
Examine and reseat major components, such as hard drive, memory.
Test with minimum configuration
removing hard drive to isolate operating system issues and testing video in F10 Setup.
If video is present, restart and retest the computer.
If video is present but bad, go to
If issue persists (no video), test with external video.
If issue persists, test or replace a confirmed working display.
If issue persists, replace discrete graphics card.
If issue persists, replace system board due to defective video function.
Check for any blink patterns. Count the number of blinks in a sequence, followed by a
pause for a few seconds.
See Status, Blinking Lights, and Error Message
troubleshooting lights, and POST error messages on page
If internal hardware components (memory, hard drive, etc.) have been recently added, a
component may not be connected properly. Remove and reseat new components
Reseat cables and connections on page
(4. Update BIOS and drivers
(9. Soft reset (Default Settings) on page
+ P for display switcher).
(11. Test with minimum configuration on page
Display on page 119 section.
(7. Status lights, blinking light codes,
92) for corrective actions.
96) one at a time.
96) if
97) by
(10.