Broadcast Electronics AM-2.5E, User Manual

Page: 173 / 320

2-2
WARNING: DISCONNECT POWER PRIOR TO SERVICING
WARNING
WARNING
DISCONNECT ALL TRANSMITTER PRIMARY POWER
BEFORE ATTEMPTING ANY EQUIPMENT MAINTE
NANCE.
CAUTION
CAUTION
REMOVING OR INSTALLING AN RF POWER MODULE
WITH THE TRANSMITTER ENERGIZED MAY RESULT
IN DAMAGE TO THE MODULE. DO NOT REMOVE THE
RF POWER MODULES WITH THE TRANSMITTER EN
ERGIZED.
2-9. Ensure all transmitter primary power is disconnected and remove an RF power module.
Clean the module of accumulated dust as required using a nylon bristle brush and vacuum
cleaner. Inspect the circuit boards for improperly seated semiconductors and components
damage by overheating. In addition, inspect the module for loose hardware. Repeat the
procedure for each module in the transmitter.
2-10.
SECOND LEVEL MAINTENANCE.
2-11. Second level maintenance is the performance of procedures required to restore an RF
power module to operation after a fault has occurred. The RF power modules contain no
electrical adjustments. Therefore, the following text presents only troubleshooting
procedures.
2-12.
TROUBLESHOOTING.
WARNING
WARNING
WARNING
WARNING
THE TRANSMITTER CONTAINS MULTIPLE CIRCUIT
GROUNDS WITH HIGH AC AND DC POTENTIALS
WITH RESPECT TO THE CABINET WHICH IS AT
EARTH POTENTIAL. DO NOT ENERGIZE THE
TRANSMITTER WITH TEST EQUIPMENT CON
NECTED TO THE TRANSMITTER OUTPUT
NETWORK, RF POWER MODULE, RF COMBINER, OR
POWER SUPPLY COMPONENTS.
CAUTION
CAUTION
REMOVING OR INSTALLING AN RF POWER MODULE
WITH THE TRANSMITTER ENERGIZED MAY RESULT
IN DAMAGE TO THE MODULE. DO NOT REMOVE THE
RF POWER MODULES WITH THE TRANSMITTER EN
ERGIZED.
2-13.
SAFETY CONSIDERATIONS.
The AM-2.5E/AM-5E transmitters are equipped with
extensive indicator and meter circuitry to allow the operator to isolate problems to a
specific area within the transmitter. Due to the hazardous voltages and currents contained
in the equipment, operation of the transmitter with test equipment connected to
transmitter output network, RF power module, RF combiner, or power supply components
is extremely dangerous and must not be attempted. Test equipment may be connected to
the ECU circuit boards from the front of the transmitter using the supplied extender
circuit board with power energized. The maintenance procedures presented in this section
should be performed only by trained and experienced maintenance personnel.
2-14. The RF power modules are not designed to be removed from the cabinet with the power
energized. Therefore, operate the transmitter to off before removing an RF power module
from the cabinet for maintenance procedures.