User's Manual

T6T VHF 100 W Transmitter Page 19 Maintenance
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(8) Remove the two screws holding the upper heatsink to the rear panel and the countersunk screw
securing it to the front of the chassis. Slowly withdraw the upper PA module from the mainframe
taking care not to snag the wiring looms. Note that SMB connector CN10 is located within the
bottom of the heatsink fins and should be disconnected using long nosed pliers. Do not attempt
to remove the connector by pulling on the cable.
(9) Remove the two screws holding the lower heatsink to the rear panel and the countersunk screw
securing it to the bottom of the chassis in front. Slowly withdraw the lower PA module from the
mainframe taking care not to snag the wiring looms.
Refitting
To refit the PA modules, proceed as follows:
(1) Place the lower PA module in position and secure it in place with the single countersunk screw
at the front and the two panhead screws at the rear. Replace the two screws that secure the
Combiner BIT module to the PA heatsink. Connect the SMB connector CN10.
(2) Route the coaxial cable with the type-N connector out the rear of the module and connect to CN1.
Replace the p-clip that was removed earlier. Ensure no wires are trapped by the module.
(3) Next, while placing the upper PA module in position, first connect SMB connector CN10 before
replacing the two rear screws and the front countersunk screw. Route the coaxial cable from
Combiner BIT module out between the PAs via the heatsink groove. Connect the type-N to CN1.
(4) Fit the four countersunk screws, previously removed, that secure the front panel to the chassis,
two at the top and two at the bottom. Replace the right-hand handle and tighten the screws
securing the left-hand handle.
(5) Connect the SMB connectors CN8 on both modules and CN13 (PA-1) and CN14 (PA-2) at the
Combiner BIT module.
(6) Connect the two flying 3-way connectors CN3 that come from CN5 (PA-1) and CN6 (PA-2) on
the Combiner BIT module.
(7) Re-establish the ac and/or dc supplies and switch power on at the radio using the rear mounted
Power switch.
(8) Ensure the front panel Ready indicator is lit and the Alarm indicator is unlit.
(9) Carry out the Calibrate routine using the Virtual Front Panel (VFP), as detailed in the procedure
To Calibrate the Transmitter on page 26.
(10) Carry out a BIT interruptive test as detailed in the procedure To Initiate a BIT Test on page 5.
(11) Set the rear panel Power switch to Standby and remove the VFP connector. Isolate the
transmitter from the ac and/or dc supplies.
(12) Refit the transmitter top and bottom covers. The transmitter can now be returned to service.