Motorola PTP 400 Series - Manual (Page 140)

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b. 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 circuited by measuring the
impedance across the Power connector. Is the lamp faulty?
9.1.2 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:
1. There is no power reaching the ODU because of a wiring fault
2. The ODU is faulty
3. The PIDU Plus is faulty
4. 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 cycling the mains power. Watch the
Ethernet indicator for 1 minute, if it never flashes then the problem is 1—3. Take the jumper
(J905) out of the PIDU Plus and check the current taken by the ODU. This should be 300mA
to 1A when starting through to running normally.
If the Ethernet indicator flashes initially 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.