Nautel NX15, Troubleshooting Manual

Page: 75 / 274

NX25/NX15 Troubleshooting Manual Responding to alarms
Issue 5.0 2016-05-06 Page 1-67
2. If you are responding to a
Rectifier Fan 1 (or 2) Fail
alarm (if not, proceed to Step 3 ), inspect
the SCR rectifier assembly’s cooling fans (see Figure 1.14 on page 1-66 ) for debris that might
restrict proper movement of the fan blades. If there is no noticeable debris, remove the
suspect fan (1 or 2, as specified by the alarm) by disconnecting its wiring and then removing
the four Philips screws securing it to the top of A72. Replace the fan with a suitable
replacement (48 V muffin fan, EBM Part # W1G110-AG07-05). Secure the replacement fan
to the SCR rectifier assembly and connect the fan’s wiring as it was previously installed.
Return the transmitter to service.
3. Disconnect all wiring attached to the SCR rectifier assembly, taking note of the wiring labels.
4. While supporting the weight of the SCR rectifier assembly, remove and save 12 sets of
mounting hardware.
5. Remove the SCR rectifier assembly from the transmitter.
6. Reverse Step 1 through Step 4 to reinstall the new or repaired SCR rectifier assembly. Ensure
all connections are tight, noting some connections have special torque requirements (e.g.,
torque the 2 AWG wires connecting to LINE 1, LINE 2 and LINE 3 to 12 N-m (106 in-lbs).
For wiring termination assistance with connections to the SCR rectifier assembly (A72),
check the wiring list in
Section 4, “Wiring/connector lists” on page 4-1 .