Power Led Is Off - Motorola PTP 300 Series User Manual

9.1.1 Power LED is Off

If the green Power LED does not light up at all, perform the following tests:
1. Remove the power lead from the PIDU Plus and test that the power source (mains or
56 V battery) is working.
2. If the main or battery power supply is working, open the flap on the left hand side of
the PIDU Plus and remove the RJ45 ODU cable from the PIDU Plus.
3. If the Power LED does not illuminate when the RJ45 ODU cable is removed:
4. If the Power LED does illuminate when the RJ45 ODU cable is removed:
5. If all tests so far have succeeded:
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i. Measure the voltage across the +55 V and 0 V pads inside the PIDU Plus
flap. An incorrect reading indicates that the PIDU Plus is short-circuited.
ii. Measure the impedance across the Power connector. An incorrect reading
indicates that the PIDU Plus is short-circuited.
iii. If both of the above tests are successful, it is likely that the PIDU Plus Power
LED is faulty.
i. Remove the jumper (J905) found inside the PIDU Plus flap.
ii. Measure the current with an ammeter placed across the two jumper pins. It
should be 10 mA with the ODU disconnected. An incorrect ammeter reading
indicates that the PIDU Plus is faulty.
i. Reconnect the RJ45 ODU cable to the PIDU Plus.
ii. Measure the current with an ammeter placed across the two jumper pins. It
should be in the range 300 mA to 1 A with the ODU connected.
iii. If the ammeter reading is too high, the ODU may be drawing too much
power, or the ODU may be short-circuited.
iv. If the ammeter reading is too low, the PIDU Plus may be supplying too little
power.
9 Troubleshooting (Fault Finding)
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