C3850 -- Power Stack only Connecting on One Side

[rsmith2720]

I am working with a C3850 2-stack, where the power stack cables are showing that they're only connected on one side. I have tried reseating and swapping the cables out for brand new ones, but switch 1 is continuing to show "not connected" while switch 2 shows "connected" and has the S-PWR light lit up green on the switch.

Power stack name: Powerstack-1
Stack mode: Power sharing
Stack topology: Standalone
Switch 1:
Power budget: 715
Power allocated: 551
Low port priority value: 22
High port priority value: 13
Switch priority value: 4
Port 1 status: Not connected
Port 2 status: Not connected
Neighbor on port 1: 0000.0000.0000
Neighbor on port 2: 0000.0000.0000

Switch 2:
Power budget: 569
Power allocated: 264
Low port priority value: 22
High port priority value: 13
Switch priority value: 4
Port 1 status: Connected
Port 2 status: Connected
Neighbor on port 1: Switch 1 - 00e1.6d21.ca00
Neighbor on port 2: Switch 1 - 00e1.6d21.ca00

[Enes Simnica]

@rsmith2720 I can tell 100% that the issue is with switch 1's power stack ports. Cause since switch 2 sees the connections but Switch 1 reports both ports as “not connected.” That usually points to a hardware problem on Switch 1 (bad power stack module or backplane), not the cables. In these kind of situations i usually check the logs with show loggings, for any stack power errors. After that verify the switch is running a supported IOS XE version, and of course If ports still don’t come up, it’s likely an RMA case for Switch 1’s power stack ports.....

check this: Catalyst 3850 Switch Hardware Installation Guide - Switch Installation [Cisco Catalyst 3850 Series Switches] - Cisco

-Enes
CCNP x2 Enterprise
Your Friendly Networking Ninja

[Jens Albrecht]

Hello @rsmith2720,

there are a few things you can try on switch 1:

• Disable and then re-enable the power-stack ports. This can be done with the commands:
  

  ! Disable power stack ports:
  stack-power switch 1 port 1 disable 
  stack-power switch 1 port 2 disable 
  ! Re-enable power stack ports:
  stack-power switch 1 port 1 enable
  stack-power switch 1 port 2 enable​

• Do a local loop test on switch 1 by connecting ports 1 and 2 with a know working cable
• Cold reboot of switch 1 (power down, pull all cables, wait a minute, recable and start) and retest

If none of these steps help, then it is probably time to RMA the switch as the power stack ports cannot be replaced.

HTH!

[MHM Cisco World]

Show version <<- check if both SW run same Ver. Or not

MHM