Nautel NG1000, Troubleshooting Manual

Page: 40 / 164

NG1000 Troubleshooting Manual Responding to alarms
Page 1-18 Issue 0.4 2010-10-12
+48 V Power Supply Replacement
See Figure
MD-5
(top view) in the Mechanical Drawings section (Section 6) of this manual.
1. Disconnect the associated VHF transmitter’s (A or B) ac power source, disconnect all cabling
from the rear of the transmitter and remove it from the system cabinet.
2. Place the VHF transmitter - top side up - on a suitable work surface. Remove the
transmitter’s top cover, noting it is secured using M3 screws.
3. Remove the four M4 screws that secure the +48 V power supply (U2) (and its mounting
brackets) to the transmitter. Retain hardware.
4. Disconnect wires # 7, 8, 9, 13 and 14 from the +48 V power supply’s terminal block, noting
their destinations.
5. Remove the +48 V power supply from the VHF transmitter and remove its brackets for use
with the new power supply.
6. Locate or obtain a replacement power supply module (Nautel Part # UG54). Install the
brackets on the new power supply and reverse Step 1 through Step 5 to reinstall the new
+48 V power supply. If necessary, refer to Table 3.7, “Wiring List - NARF62 VHF
Transmitter, 1250 W” on page 3- 6 for wiring details for U2. The transmitter should resume
normal operation and the alarm should clear.
WARNING:
Lethal voltages exist inside the system cabinet when power is on.
Follow replacement instructions carefully to ensure safety for
maintenance personnel during power supply replacement.