HP ProDesk 400 G7 SFF Maintenance And Service Manual page 64

Cause
56 Chapter 5 Troubleshooting without diagnostics
Solution
models), is set to the appropriate voltage. Proper voltage
setting depends on your region.
2. Open the access panel, and be sure that the power supply
cable is seated into the connector on the system board.
3. Check whether a device is causing the problem by removing
all attached devices (such as hard drives or optical drives and
expansion cards). Turn on the system. If the system enters
POST, then power off and replace one device at a time and
repeat this procedure until failure occurs. Replace the device
that is causing the failure. Continue adding devices one at a
time to ensure all devices are functioning properly.
4. Replace the power supply.
5. Replace the system board.
ENWW