70 CHAPTER 5: PROBLEM SOLVING
3 Power cycle the unit. To do this, remove and reconnect the AC mains 
supply. If the unit has no AC main supply, remove and reconnect the DC 
RPS supply.
4 If another fan failure warning message is generated via the Command 
Line Interface or the Web interface, return the unit to 3Com.
Unit fails, no SNMP fan failure message is received
1 Power cycle the unit. To do this, remove and reconnect the AC mains 
supply. If the unit has no AC mains supply, remove and reconnect the DC 
RPS supply.
2 Check the command line interface (display logbuffer command) 
to determine whether a thermal shutdown has occurred.
3 If no, return the unit:
If yes, check that:
■ The air vents are not obstructed.
■ The ambient temperatures and environmental conditions meet those 
specified in Appendix C.
4 Power cycle the unit. If a further thermal shutdown occurs, and all 
environmental conditions are satisfactory, return the unit to 3Com.
Error message indicating that the SFP transceiver is invalid
The Switch has identified that the SFP does not meet the minimum 
requirements for the Switch and has disabled the port. To correct this 
problem, completely remove the SFP and replace it with a 3Com 
approved SFP. See “Approved SFP Transceivers” on page 38.
Error message indicating that the SFP transceiver is faulty
To correct this problem, completely remove the SFP and then reinsert it. 
Alternatively, insert another identical SFP. If the problem persists, contact 
3Com Technical Support.