3Com Corporation
                EtherDisk Diskette for the EtherLink 16 Adapters
                                Troubleshooting
   
 
 
 If the EtherLink 16 adapter diagnostic tests fail, the adapter may not be
 defective.  Check the following:
 
 1.  Make sure the adapter is completely seated in its slot.  Review the
     installation instructions in the appropriate adapter guide. 

 2.  Inspect all cables and connections.
 
 3.  If you are running the Group 2 tests, make sure that the adapter is 
     securely connected to a loopback plug (coax version only) or to a 
     properly cabled inactive network.
 
 4.  If you are running the Group 3 tests, make sure that the adapter is 
     securely connected to a properly cabled inactive network and that an
     echo server is set up on the network.
 
 5.  Make sure that all of the adapter's option settings do not conflict with 
     any other peripheral or software program (such as 3Com's Extended Memory
     Manager) installed in the computer.  For a list of system resources
     commonly used by other peripherals, select "Additional Adapter
     Information" from the main menu, then "System Resources" from the 
     Information submenu. 
 
 6.  Make sure that the transceiver type selected is correct.
 
 7.  Running tests while connected to an active network can cause intermittent
     failures.  These failures can be avoided by using an inactive network on
     which only the computer being tested (and an echo server if running the
     Group 3 tests) is connected.

 8.  If you installed an EtherLink 16 TP adapter, check the LEDs on the back-
     plate of the adapter.  The yellow (ACT) LED is on when there is data
     transmission activity on the adapter.  This light will go on during
     the Group 2 and Group 3 tests.  The green (LNK) LED will be on when there
     is a correct connection between the adapter and the hub.  If the link
     pulse jumper is in the OFF position, the green LED will be on whether or
     not there is a connection.
 
 9.  If you have installed an EtherLink 16 TP adapter, make sure that the 
     settings for the following jumpers are correctly configured for the hub:
 
        RECEIVE THRESHOLD
        DC SIGNAL
        LINK PULSE
        EQUALIZATION
        WIRE IMPEDANCE
        TRANSMIT LEVEL
 
     For information on setting these jumpers, select "Additional Adapter
     Information" from the main menu, then "Twisted-pair Options" from the 
     Information submenu.

 10. The slot in the computer may be defective.  Install the adapter in 
     another slot and run the tests again.
 
 11. The computer in which the adapter is installed may be defective.
     Install the adapter in a known functioning computer and run the tests
     again.
 
 12. The loopback plug you are using may be defective.  Try a different
     loopback plug.
 
 13. Replace the failed adapter with a known working EtherLink 16 adapter,
     with the same jumper settings.  If the second EtherLink 16 adapter fails,
     something is wrong with the test environment, not with the adapter.
 
 
  
                       (%VER  Troubleshooting v3.4a)