HP EliteBook 850 G4 Maintenance And Service Manual page 97

A single symptom can be listed under different groups. For example, No Video can belong to (1) Power-on or
(4) Display; but Flickering when powered should be listed in (4) Display. Or, in another example, a blue screen
can be caused by a driver conflict in Performance (4), but it can also be caused by a defective hard drive under
(6) Storage. Therefore, failures that share similar symptoms are noted..
If possible, make a record of the failure symptom, the phase of the boot-up sequence where the failure
occurs, and the most likely location in the failure tree
on page 85 and
help isolate the issue and indicate the next steps. For example, when the computer is running the operating
system, it may experience an issue with (4) Display, (5) I/O devices (keyboard, wireless, and so on), (6)
Storage, or (7) Mechanical components (stuck buttons, thermal shutdown, and so on).
NOTE: "Uncategorized" is used if an issue found is not listed. For example, Bluetooth is offered on certain
hardware configurations; therefore, a Bluetooth issue can be classified under "I/O Device" if needed.
Failure classification by boot-up sequence
Table 8-3 Failure classification by boot-up sequence
1. Power-on
1. No Power on page 101
2. Intermittent power-on, shutdown,
reboot on page 103
3. AC adapter issue on page 104
4. Battery not recognized, not charging
on page 104
5. Battery discharges too fast
on page 106
6. Burnt smell on page 107
a,b,c similar symptoms
Table 8-4 Failure classification by hardware devices and mechanical on page
2. POST
1.
2.
a
3.
4.
(Table 8-3 Failure classification by boot-up sequence
No video (with power)
on page 107
Blinking lights on page 108
Diagnostics error messages
on page 109
BIOS password on page 110
86). This will
3. Performance
1.
Intermittent shutdown on page 111
2.
Blue screen (BSOD) error on page 136
3. Freeze at Windows Logo (hang/lockup)
on page 114
4. Electromagnetic Interference (EMI)
on page 115
5. No wake up on page 116
6. Unresponsive on page 117
7. Slow performance on page 117
8. HP Smart Adapter warning message
on page 118
9. Incorrect time and date on page 118
General troubleshooting steps
a
b
c
85