Lenovo ThinkServer RD650: Dead PSU, Green Light Won't Boot - Faulty Power-Latch Circuit
Introduction
This article provides a detailed context and solutions for the Lenovo ThinkServer RD650 with a dead Power Supply Unit (PSU) that won't boot, even with a green light. The server in question has 136 GB of RAM, 2 x 600 GB, and 10 x 1.2 TB SAS spinning disks.
Understanding the Power-Latch Circuit
The power-latch circuit is an essential component of the PSU that ensures the power supply is properly connected to the server. When the power-latch circuit fails, the server may not boot, even with a green light indicating that power is being supplied.
Symptoms of a Faulty Power-Latch Circuit
The most common symptom of a faulty power-latch circuit is the server failing to boot even with a green light on the PSU. Other symptoms may include intermittent power issues, random reboots, or the server not responding to power cycling.
Troubleshooting a Faulty Power-Latch Circuit
Visual Inspection
Begin by visually inspecting the PSU and power-latch circuit for any signs of damage, such as burn marks, loose connections, or visible breaks in the circuitry.
Power-Latch Circuit Test
If visual inspection reveals no obvious issues, perform a power-latch circuit test using a multimeter. Disconnect the power cable from the server and the PSU, then measure the resistance between the power-latch contacts. A good power-latch circuit should have a resistance of around 10-20 ohms.
Power-Latch Circuit Replacement
If the power-latch circuit test reveals a fault, replace the power-latch circuit. The process for replacing the power-latch circuit may vary depending on the specific model of the ThinkServer RD650. Consult the server's service manual for detailed instructions.
A faulty power-latch circuit can cause a Lenovo ThinkServer RD650 to fail to boot, even with a green light on the PSU. By following the troubleshooting steps outlined in this article, you can determine if the power-latch circuit is the issue and replace it if necessary.