Nautel NG1000, Troubleshooting Manual

Page: 35 / 164

NG1000 Troubleshooting Manual Responding to alarms
Issue 0.4 2010-10-12 Page 1-13
TXA (or TXB)
Preamp/IPA Fail TRANSMITTER A
TRANSMITTER B This alarm occurs when the associated transmitter’s
IPA has been flagged with a failure condition, due to a
current reading that is less than 50% of nominal or
greater than 150% of nominal. The nominal IPA
current reading is 3.79 A (alarm occurs below 1.90 A
or above 5.68 A). Preamp current is not monitored to
determine a failure condition.
TXA (or TXB) PS A or
B AC Fail TRANSMITTER A
TRANSMITTER B This alarm occurs when an associated transmitter’s
power supply module (U3 or U4) detects a PS AC Fail,
caused when the input ac voltage is less than 180 V
ac or above 264 V ac. These fault signals are passed
to the system controller on a serial bus. Check the ac
power source. If it is OK, suspect a fault with the
power supply module (U3 or U4). To replace a power
supply module, see
“Power Supply Module
Replacement” on page 1-17 .
TXA (or TXB) PS A or
B Missing TRANSMITTER A
TRANSMITTER B This alarm occurs when the associated power supply
is not present.
TXA (or TXB) PS A or
B Over Temp TRANSMITTER A
TRANSMITTER B This alarm occurs when the associated power supply’s
internal temperature protection circuit trips, causing it
to be inhibited.
TXA (or TXB) PS Dist
15V Flt TRANSMITTER A
TRANSMITTER B This alarm occurs when the +15 V power supply’s
output voltage is outside the acceptable range of
13.5 V to 16.5 V. Suspect a possible fault with the
+15 V supply circuitry on the PS distribution PWB
(A2).
TXA (or TXB) PS Dist
5V Fail TRANSMITTER A
TRANSMITTER B This alarm occurs when the +5 V power supply’s
output voltage is outside the acceptable range of 4.7 V
to 5.3 V. Suspect a possible fault with the +5 V supply
circuitry on the PS distribution PWB (A2).
TXA (or TXB) Reject
Foldback TRANSMITTER A
TRANSMITTER B This alarm occurs when the output power is being
limited due to excessive reject power.
TXA (or TXB) Resid
PA Volts TRANSMITTER A
TRANSMITTER B This alarm occurs when the output power is being
inhibited due to residual voltage on the power supply
(minimum acceptable level is 3 V). This must be
allowed to discharge before turning on again.
TXA (or TXB) RF Off TRANSMITTER A
TRANSMITTER B This alarm occurs when the associated transmitter
issues a command to turn itself off.
Alarm (with Prefix) Alarm/Status LED Description and Troubleshooting Action