Lenovo THINKSERVER 3821 - Manual (Page 96)

Power-supply LEDs
The following illustration shows the power-supply LEDs on the rear of the server.
1 ac power LED
2 dc power LED
3 Power error LED
The following table describes the problems that are indicated by various
combinations of the power-supply LEDs and the system power LED on the operator
information panel and suggested actions to correct the detected problems.
88 ThinkServer TD200x Types 3719, 3821, 3822, and 3823: Hardware Maintenance Manual