Description

This article explains how to troubleshoot power entry module (PEM) on devices.

Symptoms

  • Power Supply Unit is not functioning properly, when it plugged in the power feed the light indicator turns green then immediately turns red.
  • Alternately, PSU LED may also be off even when PSU is plugged in.
  • Alarm is seen as below:
> show system alarm
1 alarms currently active
Alarm time Class Description
2023-08-10 08:12:14 +03 Major PEM 1 Not Powered
 
  • PEM is not present in chassis hardware output.
> show chassis hardware
Hardware inventory:
Item Version Part number Serial number Description
Chassis xxxxxxxxxxxx EX4400-24T
Pseudo CB 0
Routing Engine 0 BUILTIN BUILTIN RE-EX4400-24T
FPC 0 REV 11 650-114381 xxxxxxxxxxxx EX4400-24T
CPU BUILTIN BUILTIN FPC CPU
PIC 0 REV 11 BUILTIN BUILTIN 24x10M/100M/1G
PIC 1 REV 11 650-114381 xxxxxxxxxxxx 2x100G QSFP28
Xcvr 0 REV 01 740-061405 xxxxxxxxxxxx QSFP-100G-SR4-T2
Xcvr 1 REV 01 740-061405 xxxxxxxxxxxx QSFP-100G-SR4-T2
Power Supply 0 REV 01 640-107105 xxxxxxxxxxxx JPSU-550-C-AC-AFI
Power Supply 1
Fan Tray 0 Fan Module, Airflow In (AFI)
Fan Tray 1 Fan Module, Airflow In (AFI)
 

 

  • Power supply is in Present state in the chassis environment :

 

> show chassis environment no-forwarding

 

Class Item              Status   Measurement

Power FPC 0 Power Supply 0      OK     24 degrees C / 75 degrees F

   FPC 0 Power Supply 1      Present

 
  • The logs are seen as below:

 

Aug 10 07:44:14  [Alarm SET] Object 75 reason 33 Device PSU-PEM 1, reason PEM 1 Absent(PEM 1 Not Present), color 1, slot 0 Alarm id 1258295329

Aug 10 07:44:14 send: red alarm set, device PSU-PEM 1, reason PEM 1 Not Present

 

  • Power supply failure logs may also be seen:

 

Oct 1 01:41:16.505 xxxxxxxxxxxx chassisd[7418]: %DAEMON-5-CHASSISD_SNMP_TRAP6: SNMP trap generated: Power Supply failed (jnxContentsContainerIndex 2, jnxContentsL1Index 1, jnxContentsL2Index 2, jnxContentsL3Index 0, jnxContentsDescr Power Supply 1 @ 0/1/*, jnxOperatingState 6)

Oct 1 02:41:18.004 xxxxxxxxxxxx chassisd[7418]: %DAEMON-5-CHASSISD_SNMP_TRAP6: SNMP trap generated: Power Supply failed (jnxContentsContainerIndex 2, jnxContentsL1Index 1, jnxContentsL2Index 2, jnxContentsL3Index 0, jnxContentsDescr Power Supply 1 @ 0/1/*, jnxOperatingState 6)

 

We can also see the below logs along with the above logs where PEM Feed shows it has no input source:

 

Mar 14 14:28:22.419 2025 xxxxxxxxxxxx alarmd[8977]: %DAEMON-4: Alarm set: PS SFXPC id=536871755, color=YELLOW, class=CHASSIS, reason=PEM 3 Feed 1 has no input source

Mar 14 14:28:22.419 2025 xxxxxxxxxxxx craftd[8477]: %DAEMON-4: Receive FX craftd set alarm message: color: 2 class: 100 object: 75 slot: 3 silent: 0 short_reason=PEM 3 Feed 1 no inp long_reason=PEM 3 Feed 1 has no input source id=536871755 reason=536870912

Mar 14 14:28:22.419 2025 xxxxxxxxxxxx craftd[8477]: %DAEMON-4: Minor alarm set, PEM 3 Feed 1 has no input source

 

Solution

  • Check the power feed and the power cable connected from the rack power source to the PEM.
  • Unplug and replug the power cable. If this does not help restore the PEM; continue:
  • Reseat the PEM physically by removing it from the chassis and reinserting it into the chassis. If this does not help restore the PEM; continue:
  • Reboot the device.
  • If the above does not work, perform a spare test - Replace the PEM with another spare working PEM and check if that comes up without error. If yes, then we can conclude that the issue lies with the PEM. 

Further issues; please contact TAC.

Modification History

2024-10-09: Added additional symptoms and log messages. 

2024-10-09: Article re-validated

Related Information

Related KB: https://supportportal.juniper.net/s/article/Junos-Major-alarm-FPC-x-PEM-not-powered-PEM-not-powered