Failure classication by hardware devices and mechanical
Table 7-4  Failure classication by hardware devices and mechanical
4. Display 5. I/O devices 6. Storage 7. Mechanical
1. Display anomalies 
on page 65
2. Dead pixel on page 67
3. No video (internal) 
on page 67
d
4. No video (external) 
on page 68
d
5. DisplayPort/VGA 
on page 68
6. HDMI on page 68
7. No or bad external video 
via docking on page 69
8. Incorrect or missing color/
distorted image 
on page 69
1. Network Connectivity 
Ethernet (RJ-45 jack) 
on page 71
2. Network connectivity 
wireless (WLAN) 
on page 72
3. USB on page 73
4. Speaker, headphone - 
audio issues on page 74
5. Thunderbolt (TB) 
on page 75
1. Hard drive/solid-state 
drive not recognized 
on page 77
2. No boot to operating 
system (no read/write 
error) on page 77
3. Read-write error 
on page 78
4. Slow performance 
on page 63
c
5. Blue screen (BSOD) error 
on page 78
b
6. Noisy hard drive 
on page 79
1. Fan error message - 90B 
on page 80
2. Noise (sound) 
on page 81
3. Fan runs constantly 
on page 82
4. HP Thermal Monitor 
on page 38
5. Stuck power button 
on page 83
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:
●
Check all cables and connections to be sure that there are no loose connections.
●
Conrm that power sources are good, such as wall power type/adapter (110V/220V ac), power strip. Test 
with a veried working AC outlet.
●
Check for compatibility issues between the computer and third-party devices, peripherals, noncertied 
devices, incompatible hardware (i.e., Mac OS device). Incompatibility can result in blue screen errors, 
improper operation, and so on.
●
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.
General troubleshooting steps 33