Nautel V10, Руководство пользователя по установке и эксплуатации

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Page 5-8
V10/V7.5/V5/V3.5 Installation and Operation Manual
Issue 3.5 Section 5 System Level Troubleshooting
NOTE
If the alarm lamp is still on after each step,
the fault remains; continue troubleshooting
at the next paragraph. If transmitter
operation is restored and the alarm lamp
turns off, the fault has been cleared.
5.5.1 Exciter Alarm
An Exciter alarm can occur if the input RF
drive (exciter power) to the active IPA
module/PA exceeds or falls below the
preset range, the mode or frequency of
the transmitter and exciter (M50 only) do
not match, or communication between the
transmitter and exciter (M50 only) has
failed. This may be a result of an exciter
fault, excessive load variation on the
active exciter output, user error, wiring
fault, or defective components on the
control/ display PWB or in the RF drive
splitter/ changeover assembly.
Troubleshoot an
Exciter alarm as follows:
NOTE
In dual exciter transmitters, when an
exciter alarm occurs, an automatic
changeover to the reserve (standby)
exciter is initiated. If the transmitter is still
operating on the reserve exciter, then
troubleshooting may be performed on the
faulty exciter, terminated with RF
termination assembly A13 using coaxial
cable W92 (from ancillary kit). Allow
operation of this exciter by removing the
REMOTE INTERFACE D-sub connector
from its rear panel.
Before attempting to troubleshoot a
suspect exciter, inhibit further exciter
changeover by setting Auto to N in the
Changeover menu. When troubleshooting
is completed restore these settings to their
factory settings.
5.5.1.1 IPA Input Low
An IPA Input Pwr Low alarm occurs if the
input RF drive (exciter power) to the active
IPA module/PA falls below the preset level
[
IPA Input Low threshold is user definable,
but is defaulted to 12 W for V10/V7.5 and
6 W for V5/V3.5 for analog configured
systems or 6 W for V10/V7.5 and 3 W for
V5/V3.5 for digitally configured systems
operating in
FM mode]. This may be a
result of an exciter fault, excessive load
variation on the active exciter output,
wiring fault, or defective components on
the control/display PWB or RF drive
splitter/changeover assembly.
Troubleshoot an
IPA Input Pwr Low
alarm as follows:
NOTE
Alarm is disabled in FM+HD or HD mode.
Exciter ALC Check: At initial turn on ( RF
On ), the input impedance of the active IPA
module (nominally 50
Ω
) varies such that
the active exciter output may be reduced. If
the exciter has an automatic level control
(ALC) circuit, verify it is enabled. An ALC
circuit will reduce the effect of load
variation on the exciter output.
Cables/Connections: Check for loose or
damaged connections on W1 (exciter A)
or W2 (exciter B, if applicable) between
the exciter output (W1P1 at A14-RF OUT,
W2P1 at A15-RF OUT – for
M50 exciters,
or A14-RF OUTPUT, A15-RF OUTPUT –
for
NE30 exciters) and the input(s) of the
RF drive splitter/changeover assembly
(W1P2 at A16A1J1 or W2P2 at A16A1J2).
Replace any damaged connections using
suitable coaxial cable (50
Ω
with near
0.695 dielectric constant material, cut to
52 inches in length).
RF Drive Checks: Check the status of the
suspect exciter, noting the use of RF
termination assembly A13, coaxial cable
W92, and the removal of
REMOTE
INTERFACE connector.
(a) Read the exciter's forward power
meter. If the forward power is:
•
stable and less than 12 W (6 W) for
analog configured V10/V7.5 (V5/V3.5)
or 6 W (3 W) for digitally configured
V10/V7.5 (V5/V3.5), see paragraph
5.5.1.1.1
'Low RF Drive'.