This article provides guidance on managing the PEM X Not Powered Alarm and outlines available solutions and also addresses below query:-

1) What all possible ways available to clear this PEM alarm ?
2) Any option suppress this PEM alarm from CLI ?

The Juniper devices may generate the "PEM X Not Powered" alarm when a power supply module (PEM) is either not operational, not in use or potentially faulty but still inserted into the chassis.
To maintain network reliability, it's crucial to address this alarm promptly.

Example:-

platform@root> show chassis hardware

Power Supply 0 REV 03 740-054405 AAAAXXXX AC AFO 1600W PSU > Suspected PEM
Power Supply 1 REV 03 740-054405 BBBBYYYY AC AFO 1600W PSU > Healthy PEM 

platform@root> show chassis alarms

1 alarms currently active

Alarm time              Class Description

2023-09-11 22:16:35 IST Major PEM 0 Not Powered

Physical Inspection- Initiate your troubleshooting process by physically inspecting the affected PEM. Ensure it is correctly seated and securely connected within its designated slot. Verify the integrity of power cables.

Replace Faulty PEM- If there's reason to suspect a PEM malfunction, we strongly recommend replacing it with a known working module. This proactive approach helps rectify potential hardware issues effectively.

Removing Suspected PEM- In cases where a PEM is not in use or deemed faulty, it's possible to clear the alarm by removing the PEM. However, exercise caution as this approach reduces redundancy and may lead to power-related issues.

Example :-

Before removing the suspected PEM -

platform@root> show chassis alarms

1 alarms currently active

Alarm time              Class Description

2023-09-11 22:16:35 IST Major PEM 0 Not Powered

After removing the suspected PEM-

platform@root> show chassis alarms

No alarms currently active

qfx10002 alarm customization limitations- Understand that alarms for PEMs are predefined and cannot be directly customized. These alarms serve as essential indicators of hardware status, and there is no option to manually suppress this alarm from the CLI.

• Kindly note that the chassis alarms are preset and cannot be modified. Please refer the link below.

https://www.juniper.net/documentation/us/en/software/junos/chassis/topics/ref/command/show-chassis-alarms.html#show-chassis-alarms-command__section_dj5_3pf_wrb