Allied Telesis AT-SBx31CFC960 - Manual (Page 235)

SwitchBlade x3112 Chassis Switch and AT-SBx31CFC960 Card Installation Guide
235
Fault Condition 4: If the LEDs on the power supply indicate normal
operations but the PSU LED on the active master control card is showing a
fault condition, the problem may be with one of the two power supply
interfaces (opto-couplers) on the rear panel of the chassis. For
troubleshooting suggestions, refer to “Power Supply Interfaces (Opto-
couplers)” on page 252.
Caution
The power supply interfaces are not hot swappable and should only
be serviced by an authorized service technician.