Chapter 8: Troubleshooting
Testing link end hardware
Page 8-8
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If the Power LED does not illuminate, confirm that the mains power supply is working, for
example, check the plug and fuse (if fitted). If the power supply is working, report a
suspected PSU fault to Cambium Networks.
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If the Power LED does illuminate, perform
Test resistance in the drop cable
Power LED is blinking
Meaning: The PSU is sensing there is an overload on the ODU port; this could be caused by a
wiring error on the drop cable or a faulty ODU.
Action: Remove the ODU cable from the PSU. Check that pins 4&5 and 7&8 are not crossed
with pins 1&2 and 3&6. Check that the resistance between pins 1&8 is greater than 100K ohms.
If either check fails, replace or repair the ODU cable.
Ethernet LED did not blink 10 times
Meaning: The ODU flashes the LED on the AC+DC Enhanced Power Injector 56V 10 times to
show that the ODU is powered and booted correctly.
Action:
1
Remove the ODU cable from the PSU. Examine it for signs of damage. Check that the ODU
cable resistances are correct, as specified in
Test resistance in the drop cable
the ODU cable is suspect, replace it.
2
Use the LPU (if installed) to check that power is available on the cable to the ODU. Access the
connections by rotating the LPU lid as shown (slacken the lid nut but do not remove it):
4
Check that test point P1 on the LPU PCB corresponds to pin 1 on the RJ45. Repeat for points
P2 to P8. This test is only valid if both the PSU and the ODU are disconnected.
5
Reconnect the ODU cable to the PSU.
6
Check that the PWR LED near the top right of the LPU PCB is illuminated to indicate power in
the Ethernet cable.
7
If any test fails, replace or repair the cable that connects the PSU to the LPU or ODU.
