Symptom
- One or both PSU's show status "Shutdown":
`show environment power detail`
Supply Model Output Input Capacity Status
(Watts ) (Watts ) (Watts )
------- ---------- --------------- ------ ---------- --------------------
1 NXA-PAC-650W-PE 86 W 90 W 650 W Ok
2 NXA-PAC-650W-PE 0 W 0 W 0 W Shutdown
- Pin, Vin and Iin will be at a normal level but Pout, Vout and Iout will be at 0.00:
`show environment power detail`
PS_2 total capacity: 0 W Voltage:12V
Pin:63.00W Vin:240.00V Iin:0.27A Pout:0.00W Vout:0.00V Iout:0.00A
Conditions
- The switch reloaded after an EPLD upgrade.
- PSU NXA-PAC-650W-[PI/PE] has serial number LIT2324XXXXX and below.
Workaround
Perform the following PSU OIR steps to clear the incorrect status:
1. remove power cables from PSU
2. wait 2 minute
3. remove PSU from chassis
4. wait 2 minute
5. insert PSU into chassis
6. wait 2 minute
7. connect power cables to PSU
The reason behind this long wait time is that power supply capacitors hold enough power to keep registers in the same state.
Further Problem Description
This issue is caused by a bug in the firmware of the PSU and it is exposed when doing an EPLD upgrade on the device which toggles the 12V power rail but not the 3.3V secondary power rail.
This issue will not be triggered by reload or power outage.
The firmware bug is only present on PSUs with serial number LIT2324XXXXX and below. Vendor added the fix in newer PSUs.
