Failure classiîžcation by hardware devices and mechanical
Table 8-5  Failure classiîžcation by hardware devices and mechanical
4. Display 5. I/O devices 6. Storage 7. Mechanical
1. Display anomalies 
on page 115
2. Dead pixel on page 117
3. No video (internal) 
on page 117
d
4. No video (external) 
on page 118
d
5. DisplayPort/VGA 
on page 118
6. HDMI on page 118
7. No or bad external video 
via docking on page 119
8. Incorrect or missing color/
distorted image 
on page 119
9. Touch screen 
on page 120
1. Keyboard on page 121
2. Keyboard point stick 
on page 122
3. Keyboard backlight 
on page 122
4. Touchpad on page 123
5. Network Connectivity 
Ethernet (RJ-45 jack) 
on page 123
6. Network connectivity 
wireless (WLAN) 
on page 123
7. WWAN on page 124
8. USB on page 124
9. Smart card reader 
on page 126
10. Speaker, headphone - 
audio issues on page 127
11. Thunderbolt (TB) 
on page 128
1. Hard drive/solid-state 
drive not recognized 
on page 130
2. No boot to operating 
system (no read/write 
error) on page 130
3. Read-write error 
on page 131
4. Slow performance 
on page 113
c
5. Blue screen (BSOD) error 
on page 131
b
6. Noisy hard drive 
on page 132
1. Fan error message - 90B 
on page 133
2. Noise (sound) 
on page 134
3. Fan runs constantly 
on page 135
4. HP Thermal Monitor 
on page 88
5. Stuck power button 
on page 136
b,c,d
 similar symptoms
     
2. Examine the environment
It is important to examine the computer’s environment. If you can quickly identify the cause of the issue, 
fewer resolution steps may be needed. Perform the following environment inspections:
â—Ź Check all cables and connections to be sure that there are no loose connections.
â—Ź Conîžrm that power sources are good, such as wall power type/adapter (110 V/220 V ac), power strip. 
Test with a veriîžed working AC outlet.
â—Ź Check for compatibility issues between the computer and third-party devices, peripherals, noncertiîžed 
devices, incompatible hardware (i.e., Mac OS device). Incompatibility can result in blue screen errors, 
improper operation, and so on.
â—Ź Isolate the computer from sources of electromagnetic interference (EMI), such as cell phones, 2-way 
radios, oor mats, fans (and other electronic motors). EMI may contribute to a display freeze issue or 
lock-up.
84 Chapter 8   Troubleshooting guide