User's Manual Part 2

T6T 300 Watt VHF Transmitter Page 120 Maintenance
Removing and Refitting the Drive Module
The Drive module is located as shown in Fig 44. A module removal diagram is shown in Fig 48.
Dangerous voltage is present within the T6T VHF drive assembly. Care must be taken by
personnel to avoid accidental contact with exposed circuitry when the covers are removed
and power is applied to the radio.
Removal
Before attempting to remove the Drive module, ensure that the drive assembly is isolated from the ac
and dc input supplies. Disconnect the six Amplifier Out connectors, CN1 to CN6. Then proceed as
follows:
(1) Remove the drive assembly top cover as described on page 116.
(2) Locate the Drive module and disconnect the following connectors:
❑ CN7 SMB connector (RF drive from PA control module CN3)
❑ CN9 SMB connector (forward power sense from PA control module CN4)
❑ CN5 3-way connector (3-wire loom from PSU regulation module CN3)
❑ CN10 6-way connector (6-wire loom from PA control module)
❑ CN11 2-way connector (2-wire loom from Processor module).
(3) Gain access to the rear of the drive assembly. Using a 5 mm nut spinner tool, remove the six
screwloc 8 mm-4-40 UNC screws that secure the Drive module ribbon cable connectors to the
rear panel. Use the same procedure to remove the three coaxial connectors from the rear panel.
(4) Remove the five M3 x 8 mm captive washer panhead screws that secure the Drive module to the
drive assembly mainframe.
(5) Remove the module from the chassis.
Refitting
To refit the Drive module, proceed as follows:
(1) Locate the module in position. Ensure no wires are trapped by the module.
(2) Secure the module to the drive assembly mainframe using the five M3 x 8 mm captive washer
panhead screws removed during the removal procedure.
(3) Using a 5 mm nut spinner, fit the 12 screwloc 8 mm-4-40 UNC screws and wavy washers that
secure the ribbon cable connectors and three coaxial connectors to the rear panel.
(4) Refit the following connectors to the module:
❑ CN11 2-way connector (2-wire loom from Processor module)
❑ CN10 6-way connector (6-wire loom from PA control module)
❑ CN5 3-way connector (3-wire loom from PSU regulation module CN3)
❑ CN9 SMB connector (forward power sense from PA control module CN4)
❑ CN7 SMB connector (RF drive from PA control module CN3).
(5) Re-connect the six Amplifier Out connectors, CN1 to CN6.
(6) Re-establish the ac and/or dc supplies.
WARNING Dangerous Voltage