User's Guide

T6T 50 W VHF Transmitter Page 13 Maintenance
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Refitting
To refit the PA Control module, proceed as follows:
(1) Place the module in position. Ensure no wires are trapped by the module.
(2) Fit the seven M3 x 8 captive washer screws that secure the module to the transmitter’s
mainframe.
(3) Refit the following connectors to the module:
❑ CN2 6-way connector (5-wire loom to PA module)
❑ CN4 SMB connector (forward power sense)
❑ CN3 SMB connector (RF drive)
❑ CN5 SMB connector (reference frequency)
❑ CN6 10-way connector (10-way ribbon cable from PSU Regulator module)
❑ CN1 50-way connector (50-way ribbon cable from Processor module).
(4) Re-establish the ac and/or dc supplies (take heed of the warning on page 12).
(5) Switch power on at the radio using the rear mounted Power switch.
(6) Ensure the front panel Ready indicator is lit and the Alarm indicator is unlit.
(7) Carry out the Calibrate routine using the Virtual Front Panel (VFP), as detailed in the procedure
To Calibrate the Transmitter on page 22.
(8) Carry out a BIT interruptive test as detailed in the procedure To Initiate a BIT Test on page 5.
(9) Set the transmitter’s internal reference frequency by carrying out the procedure detailed on
page 3.
(10) Remove the VFP connector and switch power off at the transmitter using the rear mounted
Power switch. Isolate the transmitter from the ac and/or dc supplies.
(11) Refit the transmitter’s bottom cover. The transmitter can now be returned to service.
Removing and Refitting the Power Supply
The Power Supply is located as shown in Fig 3. A module removal diagram is shown in Fig 7.
Removal
Before attempting to remove the Power Supply, ensure that the transmitter is isolated from the ac and
dc input supplies. Then proceed as follows:
(1) Remove the transmitter’s top and bottom covers as described on page 9 and page 12 (take heed
of the warnings on those pages).
(2) Support the radio on its side.
(3) Locate the power supply. From the bottom half of the unit remove the four No. 6 x 32 UNC
countersunk screws that secure the power supply to the transmitter’s mainframe. During this
operation support the power supply from the top half of the unit.
(4) Withdraw the power supply from the chassis sufficient to allow access to the power terminal
blocks taking care not to damage the ac terminal plastic supply guard.
(5) Remove the connector CN4 (power supply to the power regulator).
(6) Disconnect the dc wires from the eight connector terminal block.