-48V DC power supply in 7385 PureFlex Chassis failing during earthquake - Lenovo Flex System Carrier-Grade Chassis (7385)

Resolving The Problem

Source

RETAIN tip: H214964

Symptom

Power Supply Light Emitting Diode (LED) Input is on while Output LED is flashing and the fault LED is off. This symptom may occur during earthquakes.

Error in error log stating power supply has faulted.

Affected configurations

The system may be any of the following Lenovo x86 servers:

• Lenovo Flex System Carrier-Grade Chassis, type 7385, any model, any xxx

This tip is not software specific.

This tip is not option specific.

Solution

This behavior will be corrected in a future release of the -48V DC 2500 W power supply firmware.

The target date for this release is scheduled for second quarter 2015.

The file is or will be available by selecting the appropriate Product Group, type of System, Product name, Product machine type, and Operating system on IBM Support's Fix Central web page, at the following URL:

• http://www.ibm.com/support/fixcentral/

Workaround

Remove input power to power supply for up to 30 seconds, and then reapply input power.

Additional information

During an earthquake, the signal connection to the midplane is momentarily breaking, causing bouncing of at least some of the signals. One of the concerns is the CONTROL_N signal. It is on a short pin and thus more likely to experience momentary separation and signal bouncing.

After the earthquake, there is no longer the opportunity for the bouncing of the CONTROL_N signal. Therefore, removing and restoring the input power to the power supply will reset the signal.

The modified version of the Power Supply Firmware will tolerate bounce that may occur on the CONTROL_N signal during the earthquake.