DUA1640-5AAA028-2 C HAPTER 8: PROBLEM S OLVINGSolving ProblemsWith the HubPower LED not lit. Check your power cord connection. If theconnection is secure and there is still no power, you may have a faultypower cord which needs replacing with another PS Hub power cord.If you have another PS Hub, try that hub’s power cord with this hub toisolate whether the fault is with the power cord or the hub.Power LED yellow. The hub has failed its self-test due to an internalproblem, you need to contact your supplier.Port Status LED yellow (PS Hub 40) or flashing green (PS Hub 50)for a 10Mbps transceiver module port. It is likely that there is aloop in your network which has caused this port to partition. Examineyour connections and remove the loop. Each piece of equipmentneeds only one connection to your stack.Port Status LED flashing green for a 10BASE-T port. It is likely thatthere is a loop in your network which has caused this port to partition.Examine your connections and remove the loop. Each piece ofequipment needs only one connection to your stack.Port Status LED not lit for a port that has a connection. There is aproblem with this connection. Check you are using a‘Straight-through’ 10BASE-T cable which is properly connected at bothends, is not damaged, and that the equipment it is connected to ispowered on and operating correctly.Link between two PS Hubs not working. Check your stackconnections; follow the information given in “Connecting PS HubsTogether (Stacking)” on page 3-12.Link between two stacks not working. Check your hubconnections; follow the information given in “Connecting DifferentHubs and Stacks to Your Hub” on page 3-16. It is likely an MDI/MDIXswitch is incorrectly set.Segment LEDs constantly lit. There may be a network loop causedby connecting the segments with:n An external switch in addition to the segment switch in aPS Hub 50.n Multiple external switches.
