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If neither is illuminated then there is no voltage on the power wires to the ODU.
• Check that the mains power is connected and switched on.
• Check that the lamp illuminates if the ODU connector is disconnected at the PIDU Plus
(Remove the PIDU Plus cover).
If it does illuminate then either the ODU is drawing too much current, or the power wiring to the ODU
is short circuit or the PSU is supplying insufficient power. The likely fault can be determined by
removing the jumper (J906), found inside the removable cover of the PIDU Plus, and measuring the
current taken with an ammeter placed across the 2 jumper pins. This is normally 10mA without the
ODU connected and 300mA to 1A when the ODU is connected.
If it does not illuminate then recheck that power is applied to the PIDU Plus by measuring the voltage
across +55V and 0V pads inside the removable cover in the PIDU Plus. Check that the PIDU Plus is
not short circuit by measuring the impedance across the Power connector. Is the lamp faulty?
10.1.2 Ethernet
The Ethernet LED is driven from the ODU processor and thus is capable of informing you of
many conditions using different flash sequences. If the Ethernet indicator does not illuminate
at all there are four possible conditions.
• There is no power reaching the ODU because of a wiring fault
• The ODU is faulty
• The PIDU Plus is faulty
• The Ethernet network side is faulty
Look at the following table to check the LED response for power up, disconnect the power
and reapply and note what happens.
Differentiating between 1-3 and 4 can be achieved by removing the power for 1 second.
Watch the Ethernet indicator for 1 minute, if it never flashes then the problem is 1-3. Take the
jumper (J906) out of the PIDU Plus and check the current taken by the ODU. This should be
300mA to 1A when starting to running normally.
If the Ethernet indicator flashes to begin with but then stops flashing, the ODU is powered and
software loaded but Ethernet connectivity has been lost between the ODU and the users
connected equipment. All Ethernet connections should be rechecked.