Fast EtherHub-12s User’s Guide
A-2 Troubleshooting
System Diagnostics

Power and Cooling Problems

If the Power indicator does not turn on when the power cord is plugged in, you
may have a problem with the power outlet, power cord, or internal power
supply as explained in the previous section. However, if the unit powers off
after running for a while, check for loose power connections, power losses or
surges at the power outlet, and verify that the fan on back of the unit is
unobstructed and running prior to shutdown. If you still cannot isolate the
problem, then the internal power supply may be defective. In this case, contact
your Accton distributor for assistance.

Installation

Verify that all system components have been properly installed. If one or more
components appear to be malfunctioning (e.g., the power cord or network
cabling), test them in an alternate environment where you are sure that all the
other components are functioning properly.
Cabling
1. Verify that the cabling type is correct. Be sure all cable connectors are
securely seated in the required ports. Use 100W Category 5 straight-through
cable for all standard twisted-pair connections.
2. Make sure all devices are connected to the network. Equipment may have
been unintentionally disconnected from the network.
3. When cascading two devices using RJ-45 station ports at both ends of the
cable (i.e., not the MDI port), make sure a crossover cable is used. Crossover
cable should only be used if a daisy-chain port is not available.