HP Z220 SFF, Z220 CMT, Z420, Z620, and Z820 Workstations Maintenance and Service Guide

Problem Cause Solution
b. Replace one device at a time and repeat this
procedure until a failure occurs.
c. Replace the device causing the failure
d. Continue adding devices one at a time to verify
that all devices are functioning.
2. Verify power supply functionality.
a. Disconnect AC power.
b. Remove the Z820 PSU from the chassis.
c. Unplug all system board power cables for the
Z220 CMT, Z420, and Z620.
d. Plug in AC power.
●
If the PSU fan spins and the LED
illuminates (see
Testing power supply
on page 129), the power supply is good.
Replace the system board.
●
If the PSU fan does not spin or the LED
does not illuminate (see
Testing power
supply on page 129), replace the power
supply.
130 Chapter 4 Diagnostics and troubleshooting