NX50 Troubleshooting Manual
Responding to alarms
Page 1-80
Issue 6.0 2019-04-01
Rectifier Fan Inspection/Replacement
See
1. Set the transmitter to its RF Off state and turn off (disable and lock out) the ac power
at the source. Lift the air filter (slide it up) to verify the LEDs on the power module
interface PWBs are off (green when on), indicating the B+ capacitors are
discharged.Open the rear door of the cabinet and verify the three ac indicator LEDs on
the rectifier assembly are off (amber when on). For additional safety, measure the dc
voltage across the + and - terminals of any of the large, electrolytic capacitors on the
floor of the cabinet as well as the line-to-line and line-to-ground voltages at the ac input
terminals. There should be little or no ac or dc voltage. DO NOT PROCEED if either
the ac or dc voltage is greater than 5V.
2. Inspect the SCR rectifier assembly’s cooling fans
(see
) for
debris that might restrict proper movement of the fan blades. Try spinning the fan
blades to loosen or free any blockages that may be causing the
Rectifier Fan 1 (or 2) Fail
alarm.
3. 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 A48.
4. Replace the fan with a suitable replacement (Nautel Part # 207-8378).
5. Secure the replacement fan to the SCR rectifier assembly and connect the fan’s wiring
as it was previously installed.
6. Return the transmitter to service and verify the fan RPM meter values in the AUI
menu. Ensure both fans are operating effectively and at relatively similar speeds.
WARNING:
Lethal voltages exist inside the transmitter when the power is turned
on. Turn off (disable) and lock out the power at the source and verify
no dangerous ac or dc voltages are present before removing any
connections or PWBs.
Summary of Contents for NX50
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Page 8: ...NX50 Troubleshooting Manual Page viii Issue 6 0 2019 04 01...
Page 10: ...NX50 Troubleshooting Manual Page x Issue 6 0 2019 04 01...
Page 108: ...NX50 Troubleshooting Manual Responding to alarms Page 1 98 Issue 6 0 2019 04 01...
Page 153: ...NX50 Troubleshooting Manual Reading Electrical Schematics Page 4 6 Issue 6 0 2019 04 01...
Page 184: ...Issue 6 0 2019 04 01 MD 4 Figure MD 4 NAPI95A 01 Power Module Interface PWB...
Page 188: ...Issue 6 0 2019 04 01 MD 8 Figure MD 8 NAPI106 Remote Interface PWB...
Page 192: ...Issue 6 0 2019 04 01 MD 12 Figure MD 12 NAPI98 RF Drive Distribution PWB...
Page 198: ...Issue 6 0 2019 04 01 MD 18 Figure MD 18 Fan Tray Assembly 207 8133 B1 B2 J1 AIR FLOW AIR FLOW...
Page 201: ...Issue 6 0 2019 04 01 MD 21 Figure MD 21 NAFP106B 01 Directional Coupler A1 DETAIL...
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