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ADCP-75-214 • Issue 2 • September 2006
Page 11
© 2006, ADC Telecommunications, Inc.
3 TROUBLESHOOTING
When a fault occurs with the system, the red alarm LED on the PDU and the PDU dry-alarm
contact are activated. In such a case, troubleshoot for problems as follows:
1. Check that power is present at the PDU. The PDU will not operate if DC is not present,
polarity is incorrect, or the DC presented is out of specifications (–56 to –20 VDC or +20
to +56 VDC).
2. Each MHU output has a status LED. Status LED for each MHU that is in use should be
GREEN.
3. Disable or disconnect any unused MHU ports to prevent false alarm conditions.
4. Verify that DC voltage is present at the MHU port on the PDU. Disconnect the MHU
(Bias-T) cable and measure output voltage using a multimeter (Voltage measurement,
DC). Nominal DC output power should be 14–16 VDC.
5. Verify that DC voltage is present at the antenna side of the Bias-T. Disable RF transmit
power or disconnect it from the BTS. Disconnect antenna feeder cable from ANT side of
Bias-T and measure voltage using a multimeter (Voltage measurement, DC). Nominal DC
output power should be 14–16 VDC.