Paradyne 7511 User Manual

5-17511-A2-GB20-00 June 1997Troubleshooting5TroubleshootingThis DSU is designed to provide you with many years of trouble-free service. If aproblem occurs, however, refer to Table 5-1 for possible solutions.Table 5-1. Troubleshooting (1 of 2)Symptom Possible Cause RecommendationsAn Alarm LED is on. One of several alarmconditions exists: Power-on self-test failed No DDS signal Out of Service Out of Frame Crossed pair detected Bit errors detectedduring loopback test(which also causes anOut of Frame condition) If the NS LED is lit:– Verify that the DSU isconnected to the network– Request a CSU loopback fromyour network service provider If the OOS LED is lit:– Check the status of the remoteDSU– Initiate a Remote Loopback Try a different DSU with thesame network connection. If theproblem persists, contact yourservice representative.Power-Up Self-Testfails. Only theAlarm LEDs are onafter power-up.The DSU has detected aninternal hardware failure. Reset the card and try again. Contact your servicerepresentative.An LED is not lit. LED is burned out. While the DSUs are not in use,cycle power to the card by pulling itslightly out of the carrier thenreplacing it. If the LED in questiondoes not flash with the other LEDs,contact your service representative.No power, or theLEDs are not lit. The power supply to thecarrier has failed. The card is not seatedproperly.If other devices in the carrier arefunctioning, verify that the DSU cardis properly seated and locked inposition.