Appendix C - Ground Faults | |
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HIGAIN FAULT ISOLATION
Solutions for common problems that may occur with the
| Table 9. Fault Isolation Guide |
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Problem | Solution |
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LED does | 1 Verify that the HLU is installed and operational in the CO. |
not light | 2 Verify proper cabling between the doubler enclosure and the CO. |
| |
| 3 Measure 100 to 200 Vdc between pins 5 or 6 and 8 or 9. This voltage |
| peaks every 15 to 30 seconds as the HLU cycles between self test and |
| line power. If less than 100 Vdc is present, check the cabling or the HLU. |
| Only the line units mentioned in the “Applications” section can be used |
| to power doublers (see Table 3 on page 6). Other HLU models may not |
| provide reliable operation and should not be used. |
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LED | Synchronization is being attempted with the upstream unit. |
continues to |
|
flash green |
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once a |
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second |
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The HLU at the CO is not present. Measure the resistance of the HDSL input | |
loses power | loop. Resistance should be normal loop resistance plus the 25Ω signature |
| of the HLU. |
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|
HDSL line | A grounded pair is being detected by either the HLU or |
power only | This causes the unit’s GFD circuit to trigger which forces the HDSL line |
appears in | voltage off immediately after it cycles on. Remove the HLU and |
very short | and check for cable ground faults in Span 1. The doubler’s GFD circuit can |
bursts | easily be checked by grounding any of the loop connectors to the doubler. |
| This forces the circuit down immediately. If the circuit stays up, either the |
| GFD circuit is defective or the |
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A grounded pair is being detected by the | |
shuts off | |
after Span 1 |
|
comes up |
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30 | April 30, 2003 |