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error HP
Error Code Power LED blinks red, 4 blinks with a pause
Power failure or overload detected on the power supply.
? What Causes This
Overloaded or faulty PSU; incorrect setup or cabling issue.
✓ How to Fix It
Unplug all non-essential devices, check and correct any misconfigurations, replace PSU if needed.
Source: page 2 of the official manual
From the manual
This error code appears in:
HP Prodesk 600 G1 Small Form Factor PC