Maintenance and Service Guide

Table 8-9 Issues, possible causes, and xes (continued)
Items Procedures
Verify blinking lights (7. Status lights, blinking light codes, troubleshooting lights,
and POST error messages on page 89)
At this point, there should be sucient power from the AC adapter to the system
board. Expect to hear the fan spinning and see blinking lights or error messages (i.e.,
faulty memory, HDD, etc)
Verify system board
1. Test essential hardware conguration (11. Test with minimum conguration
on page 93, 12. Test with veried working conguration (hardware and/or
operating system) on page 94, 13. Replace the system board on page 94) by
removing nonessential parts.
2. If there is still no boot, replace system board.
Tips and tricks Computer automatically boots without pressing power button when RTC 3V battery
has been removed. Therefore, after the service door and RTC 3V battery are removed,
no need to press power button from top side.
In essential hardware conguration, mWS G1 and G2 may require discrete GPU to boot.
However, mWS G3 can boot with integrated graphics.
Intermittent power-on, shutdown, reboot
Table
8-10 Issues, possible causes, and xes
Items Procedures
Symptoms
● Does not always turn on
● Intermittently hangs
● Intermittently shuts down
● Spontaneously reboots
Possible causes
Electrical short, uctuating power source, unstable power rails, loose connections, bent pins,
stray wires, dust, obvious damage, nearly faulty parts (bulging/leaking capacitor).
Potentially will turn into a no power issue soon (No Power on page 97).
Troubleshooting steps
1. Visually check power ports on both AC adapter and computer sides.
2. Inspect power sources:
a. Verify AC adapter working correctly. Use a conrmed working adapter to test.
b. Verify that battery is not depleted while system is in the Sleep state. Test with a
conrmed working battery.
The sections below are intended for authorized service providers/technicians.
1. Follow actions in No Power on page 97.
a. Be sure that AC adapter has correct DC voltage.
b. Verify battery - test with a conrmed working battery.
c. Verify that power button is not stuck.
d. Verify that power connector is not loose.
e. Verify that Power Good LEDs are solid.
Common issues and possible solutions 99