This article explains how to troubleshoot the "PEM * Not Powered" alarms or log messages that the system may report on QFX 10K and MX 10K devices.

Log Message

QFX10008 alarmd[7231]: %DAEMON-4: Alarm set: PS SFXPC color=YELLOW, class=CHASSIS, reason=PEM 0 Not Powered
QFX10008 alarmd[7231]: %DAEMON-4: Alarm cleared: PS SFXPC color=YELLOW, class=CHASSIS, reason=PEM 0 Not Powered

Alarm

root@QFX10008> show chassis alarms 
Minor  PEM 1 Not Powered
Minor  PEM 0 Not Powered

On QFX10K and MX10K devices, we support upgrading the primary firmware via ISP (Firmware upgrade procedure) for all power supplies that have the following part numbers:

• 740-049388

• 740-073146

To identify the part number, use the following command:

root@lab-re1> show chassis hardware

To map part numbers and model numbers, refer to KB9475 - Mapping between FRU part numbers and model numbers [juniper.net].

Note: This support to upgrade firmware is available for all PSUs that were manufactured between January 2022 and December 16, 2022. For PEMs shipped after Dec 20, 2022, you do not need any upgrade because the PSUs already contain the new firmware.

We recommend that you try an upgrade of firmware and if you run into any issues, you can connect with JTAC.

However, you do not need a special image for this upgrade. The Junos OS images already consist of this firmware image. The Junos OS images that have this firmware fix include Junos OS Release 21.2R3-S5, Junos OS Release 23.1R2, Junos OS Release 23.2R1, and Junos OS Release 23.3R1 and later.

There are two firmware options for every PSU: primary and secondary. To identify the firmware version, use the following command:

root@QFX10008> show chassis firmware | grep pem
PEM 0          MCU    0x14.0x36                 
PEM 1          MCU    0x14.0x36                  
PEM 2          MCU    0x14.0x36               
PEM 3          MCU    0x1a.0x3a
PEM 4          MCU    0x1b.0x3a

In the above output, 0x14, 0x1a, and 0x1b represent the primary firmware versions, whereas 0x3a and 0x36 correspond to the secondary firmware versions.

To address the "PEM * Not Powered" issue, we recommend that you perform a firmware upgrade of the primary firmware of the PSU.

Note: Primary firmware versions earlier than 0x1a do not support ISP upgrade. In such cases, an RMA is required for the affected PEMs.

Procedure to upgrade the firmware:

Use the command "request system firmware upgrade pem slot <pem slot number>" to initiate the firmware upgrade.

For example:

root@QFX10008> request system firmware upgrade pem slot 3

Wait for 10 minutes for the upgrade to complete. Ensure that you perform the upgrade one by one if the upgrade has to be done on multiple PEMs.

Lastly, to verify the new version of the PEM, execute show chassis firmware | grep PEM.

For more detailed information, refer to KB75894 - [QFX10K] "PEM X Feed X switch OFF but input connected" alarm [juniper.net].

2023-12-08: Initial version

2023-12-26: Minor non-technical modification

2024-02-23: Added a reference KB number to the Solution section