Nautel NX15, Troubleshooting Manual

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NX25/NX15 Troubleshooting Manual Responding to alarms
Page 1-68 Issue 5.0 2016-05-06
Low Voltage Power Supply Replacement
See Figure 1.15 on page 1-68 .
1. Turn off the ac power at the source. Open the back door and verify the green LEDs on the
power module interface PWBs are off, indicating the capacitors are discharged. For
additional safety, measure the dc voltage across the + and - terminals of any of the large,
electrolytic capacitors on the floor of the cabinet. There should be little or no voltage.
2. Disconnect all wiring attached to the affected power supply module (U3 through U7), taking
note of the connector labels on the cables.
Figure 1.15: Location of Low Voltage Power Supplies U3 through U7
3. Remove and save four sets of mounting hardware.
WARNING:
Lethal voltages exist inside the transmitter when the power is turned
on. Turn off the power at the source and wait until the 10 bright
green LEDs on the power module interface PWBs - in the back of each
cabinet - are off before removing any connections or assemblies.
15 V Power
Supplies
U3 (A) and U4 (B)
Back Door and Side Panel
Removed for Clarity
48 V Power
Supplies
U5 (A) and U6 (B)
12 V Power
Supply U7