Broadcast Electronics AM-2.5E, User Manual, Page: 147 / 320

2-2
WARNING: DISCONNECT POWER PRIOR TO SERVICING
WARNING
WARNING
DISCONNECT ALL TRANSMITTER PRIMARY POWER
BEFORE PROCEEDING.
2-9. Ensure all transmitter primary power is disconnected and clean a circuit board of
accumulated dust as required using a nylon bristle brush and vacuum cleaner. Inspect
the circuit board for improperly seated semiconductors and components damage by
overheating. In addition, inspect the circuit board for loose hardware. Repeat the
procedure for each power supply circuit board in the transmitter.
2-10.
SECOND LEVEL MAINTENANCE.
2-11. Second level maintenance is the performance of procedures required to restore a power
supply circuit board to operation after a fault has occurred. The power supply circuit
board contains no 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.
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.
REMOVING/INSTALLING A POWER SUPPLY CIRCUIT BOARD.
A power supply circuit
board is removed by disconnecting three connectors, loosening the mounting hardware,
and sliding the circuit board from the mounting pins. To remove or install a power supply
circuit board, proceed as follows:
WARNING
WARNING
DISCONNECT ALL TRANSMITTER PRIMARY POWER
BEFORE PROCEEDING.
2-15. Disconnect all transmitter primary power.
2-16. To remove a power supply circuit board, proceed as follows:
1. Refer to Figure 5-2/5-3 in SECTION V, MAINTENANCE and locate the desired
power supply circuit board to be removed.