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Table Of Contents

EX7100 Technical Manual - Module Descriptions

Due to the interaction between the filter components, it is advisable to repeat this

procedure a number of times.

5. Disconnect the analyser. Reconnect the Duplexer to SK101 and the Receiver Module

to SK102.

6. Disconnect the analyser. Reconnect the Duplexer to SK101 and the Receiver Module

to SK102.

Note: The Duplexer module must also be adjusted to suit the new centre frequency

(refer to Section 7.10.3 for tuning details).

Receiver Maintenance Adjustments

The baseband DC offset may drift with age. To check or adjust:

1. Connect an oscilloscope in XY mode to PL301 (pins 1 and 3). Ensure that the

oscilloscope is DC coupled and centred on the display.

2. Disable the transmitter by setting the terminal to On-demand operation in the

Terminal Set-up menu (Refer to Section 3 for details).

3. Put the EX7100 terminal into Align Mode with CW and Tx: Low selected. (Refer to

Section 4.5.1).

4. Apply an un-modulated RF carrier at approximately –80dBm on channel into the

receiver (W101)

5. A circle should appear on the oscilloscope. Adjust the signal generator RF level for a

circle of ~2 volts peak to peak diameter.

Adjust RV301 and RV302 to centre circle about 0 volts (i.e. remove the DC offset).

7.8.4 UHF Receiver Replacement Procedure

Note: It is necessary to remove the Front-End module prior to replacing the Receiver

module, however, the Front-End module can be replaced without removal of the

Receiver module.

Removal of the Type 8055 Front-End Module

1. Isolate the EX7100 Terminal from the incoming DC supply by removing the DC input

wires from the rear panel terminal block.

2. Remove the bottom cover as described in Section 6.1.

3. Note the connector positions and the way that the cables are run (it is important that

all cables are replaced as they were initially run before the module replacement

procedure).

4. Remove coaxial connectors SK101 & SK102 from the Receiver Front-End module

and connector PL104 from the Receiver board.

5. Remove the four screws holding the Receiver Front-End module and lift the Front-

End PCB out of the casting.

6. Position the new Receiver Front-End Module and replace the four mounting screws.