10 000 WATT FM BROADCAST TRANSMITTER
FM10
Page 5-25
01 October 2002
5.11.8.3.3
High RF Drive
: The exciter power has
probably exceeded the high RF drive threshold
(nominally 33 watts). Decrease the exciter output
power until the voltage at A14TP7, representative of
the RF drive level, is the level specified as
RF Drive
Level [___ Fwd Pwr]
in table 5-6.
NOTE
The control/monitor PWB's RF drive monitor
circuitry generates an exciter interlock control
signal to mute the exciter's RF output for a nominal
five second interval. This signal is generated each
time the exciter's output exceeds 33 watts.
5.11.9
IPA OUTPUT ALARM:
An
IPA
OUTPUT
alarm can occur if the average detected RF
level at the combiner splitter of the RF power
modules falls below a preset threshold. Trouble
shoot an IPA output alarm as follows:
5.11.9.1 IPA Module Low Supply Voltage
Check:
Determine whether the IPA switching power
supply's output voltage is too low as follows:
(a)
Set the control/monitor panel's
DC SUPPLY-
Volts
switch to
IPA
.
(b)
Monitor the IPA power supply's output voltage
on control/monitor panel's
DC SUPPLY-Volts
meter. Record the meter reading.
(c)
If the meter reading in step (b) is not near the
voltages recorded as
IPA VDC
in table 5-6
Factory Determined Measurements for
Critical Parameters
, the IPA power supply
requires adjustment or has failed.
(d)
If the meter reading in step (b) is near 0.0 VDC
and the
PWR SPLY FAIL IPA
lamp is not on (see
paragraph 5.11.13), it is probable that a power
amplifier in the IPA module has failed.
5.11.9.2 IPA Module Replacement:
Replace the
IPA module as follows:
(a)
Temporarily replace the IPA module with an
operational RF power module as detailed in
paragraph 5.8.
(b)
Trouble shoot the IPA module as detailed in the
IPA module's service instruction manual.
5.11.9.3 Control/Monitor PWB IPA Output
Monitor Check:
Determine whether the
control/monitor PWB's
IPA Output
circuit is
defective as follows:
(a)
Measure the DC voltage between TP5 (+) on
the control monitor PWB (A14) and ground (-).
Record the meter reading.
(b)
If the digital multimeter reading is not near the
voltage recorded as
IPA Fwd Pwr Level
in
table 5-6, check the cables and connectors
between the six-way splitter and the IPA
module.
NOTE
If the transmitter RF output is inhibited, use the
[PA
VDC set for minimum]
values for TP5. If it is
operating normally, use the
[PA VDC set for
Assigned FWD PWR]
value.
(c)
If the reading in (a) is not near the level
determined in step (b), the control/monitor
PWB's circuitry may be defective. To trouble
shoot the circuitry, refer to the control/ monitor
PWB's service instruction manual.
5.11.10
IPA SWR ALARM:
An
IPA SWR
alarm
can occur when the forward or reflected power of the
IPA module level exceeds a preset threshold.
Remedial action on an
IPA SWR
alarm should be
taken as follows:
5.11.10.1 IPA Reflected Power:
Determine whether
an excessive IPA reflected power level caused the
alarm as follows:
(a)
If the
IPA SWR
alarm is on and the transmitter
has not been latched off, check cables between
the IPA combiner/splitter probe's output and
the RF power module inputs for loose
connectors and intermittent cabling.
(b)
If the
IPA SWR
alarm is on and the transmitter
has been latched off, check for open or short
circuit on the cables between the IPA combiner/
splitter probe's output and the RF power
module inputs. Press
PROTECT RESET
.
If the
fault has cleared, the transmitter will resume
operation.
Summary of Contents for FM10
Page 173: ...Figure SD 1 Electrical Schematic FM10 FM Broadcast Transmitter Overview Page SD 1 15 July 1997...
Page 174: ...Figure SD 2 Electrical Schematic AC DC Power Supply Sheet 1 of 2 Page SD 2 15 July 1997...
Page 175: ...Figure SD 3 Electrical Schematic AC DC Power Supply Sheet 2 of 2 Page SD 3 15 July 1997...
Page 177: ...Figure SD 5 Electrical Schematic 3 Phase Monitor PWB NAPC60 03 Page SD 5 15 July 1997...
Page 178: ...Figure SD 6 Electrical Schematic RF Power Stage Sheet 1 of 2 Page SD 6 15 July 1997...
Page 179: ...Figure SD 7 Electrical Schematic RF Power Stage Sheet 2 of 2 Page SD 7 15 July 1997...
Page 180: ...Figure SD 8 Electrical Schematic RF Combiner Final Filter NAF79 Page SD 8 15 July 1997...
Page 181: ...Figure SD 9 Electrical Schematic Control Monitor Function Page SD 9 15 July 1997...
Page 182: ...Figure SD 10 Electrical Schematic Control Display PWB NAPD05 01A Page SD 10 15 July 1997...
Page 185: ...Figure MD 1 Assembly Detail FM10 FM Broadcast Transmitter Front View Page MD 1 15 July 1997...
Page 186: ...Figure MD 2 Assembly Detail FM10 FM Broadcast Transmitter Rear View Page MD 2 15 July 1997...
Page 189: ...Figure MD 5 Assembly Detail NAG02 01 NAG02 02 Circuit Breaker Panel Page MD 5 15 July 1997...
Page 190: ...Figure MD 6 Assembly Detail NAC76 Power Supply Control Panel Page MD 6 15 July 1997...
Page 192: ...Figure MD 8 Assembly Detail NAPD05 01A Control Display PWB Page MD 8 15 July 1997...
Page 193: ...Figure MD 9 Assembly Detail NAI07 Intermediate RF Drive Splitter Page MD 9 15 July 1997...
Page 194: ...Figure MD 10 Assembly Detail NAFP68 IPA Input Power Probe Page MD 10 15 July 1997...
Page 196: ...Figure MD 12A Assembly Detail NAS43 02 Low Voltage Power Supply Page MD 12A 15 July 1997...
Page 197: ...Figure MD 12B Assembly Detail NAS43 02A Low Voltage Power Supply Page MD 12B 15 July 1997...
Page 199: ...Figure MD 14 Assembly Detail NAPC60 03 3 Phase Monitor PWB age MD 14 15 July 1997...