Fast EtherHub 3500 System 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 fans on back of
the unit are 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.
Transmission Mode
If any devices are attached to the 100BASE-TX or FX
SmartExtender Module, and operate at full duplex but do not
support auto-negotiation, then you must manually set the
transmission mode for this port on the hub. (Refer to Configuring
Port Parameters in Chapter 5.)
The default method of selecting the transmission mode for the
100BASE-TX and FX extender module is auto-negotiation.
Therefore, if the Link si gnal is disrupted (e.g., by unplugging the
network cable and plugging it back in again, or by resetting the
power), the port will try to reestablish communications with the
attached device via auto-negotiation. If auto-negotiation fails,