Larcan MXI1503U User Manual

MXI1503-2004 OPERATIONS AND MAINTENANCE

CONTENTS

1 THE MXI1503-2004 TRANSMITTER ............................................................................................................................ 3

2 MXi AMPLIFIER ASSEMBLY ....................................................................................................................................... 4

3 MXi AMPLIFIER CONTROLLER ................................................................................................................................ 5

4 MAIN CONTROL CHASSIS ........................................................................................................................................... 6

5 AMPLIFIER INSTALLATION AND STARTUP .......................................................................................................... 7

5.1 BEFORE APPLYING AC TO THE UNIT ............................................................................................................................ 7

5.2 APPLYING AC TO THE UNIT .......................................................................................................................................... 7

5.3 BEFORE TURNING THE AMPLIFIER ON ......................................................................................................................... 7

5.4 AMPLIFIER ON SEQUENCE ............................................................................................................................................ 8

5.4.1 Turning ON the Transmitter ................................................................................................................................ 8

5.4.2 TYPICAL DATA read on the LCD ....................................................................................................................... 9

6 TEST AND TROUBLESHOOTING ............................................................................................................................. 10

6.1 BENCH TEST PROCEDURES ......................................................................................................................................... 10

6.1.1 Front-End Module, 21B2860G7, Bench Test Procedure ................................................................................... 10

6.1.2 Driver Pallet, 21B2708G3, Bench Test Procedure ............................................................................................ 10

6.1.3 PA Pallet 21B2729G1 Bench Test Procedure.................................................................................................... 10

6.1.4 Amplifier AGC Setup .......................................................................................................................................... 10

6.2 BASIC TROUBLESHOOTING TECHNIQUES .................................................................................................................... 12

6.2.1 No RF Output ..................................................................................................................................................... 12

6.2.2 Output Reduced by 45% (for MXi1503) or 60% (for MXi2004) ........................................................................ 12

7 MAINTENANCE ............................................................................................................................................................. 13

7.1 DAILY ......................................................................................................................................................................... 13

7.2 MONTHLY ................................................................................................................................................................... 13

7.3 SEMI-ANNUALLY AND ANNUALLY ............................................................................................................................. 13

7.4 TRANSMITTER COOLING SYSTEM ............................................................................................................................... 13

8 SERVICE ......................................................................................................................................................................... 14

8.1 REMOVING THE FAN ARRAY ....................................................................................................................................... 14

8.2 REPLACING THE ENTIRE FAN ARRAY ......................................................................................................................... 15

8.3 REPLACING A SINGLE FAN .......................................................................................................................................... 15

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FIGURES

FIGURE 1 MXI AMPLIFIER HEATSINK ASSEMBLY ........................................................................................................................ 4

FIGURE 2 MXI CONTROLLER ........................................................................................................................................................ 5

FIGURE 3 MAIN MENU .................................................................................................................................................................. 7

FIGURE 4 INTERLOCKS STATUS .................................................................................................................................................... 8

FIGURE 5 TRANSMITTER ON WITH FULL DRIVE ........................................................................................................................... 8

FIGURE 6 AGC ADJUSTMENT ....................................................................................................................................................... 9

FIGURE 7 BOTTOM VIEW OF MXI ................................................................ ................................................................ ............... 14

FIGURE 8 FAN ARRAY ................................................................................................................................................................ 15

FIGURE 9 FAN ATTACHMENT TO MOUNTING PLATE ................................................................................................................... 15

FIGURE 10 RF FLOW FOR MXI1503 ........................................................................................................................................... 16

FIGURE 11 RF FLOW FOR MXI2004 ........................................................................................................................................... 17

FIGURE 12 MXI1503 INTERCONNECT DIAGRAM ........................................................................................................................ 18

FIGURE 13 MXI2004 INTERCONNECT DIAGRAM ........................................................................................................................ 19

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1 THE MXI1503-2004 TRANSMITTER

This publication describes the operation and maintenance of both the MXi1503 and MXi2004. These transmitters
are very similar, only differing in the number of amplifier and power supply modules. The MXi1503 is comprised
of 3 Amplifier and 3 Power Supply modules where as the MXi2004 is comprised of 4 Amplifier and 4 Power
Supplies. In both cases each power supply is connected to an individual amplifier.

In addition to the Amplifiers and Power Supplies both transmitters consist of a Main Control Chassis,
Driver/Splitter Assembly (either 3-way or 4-way), Combiner and Reject Load Assembly (either 3-way or 4 –way
combiner) and Front End (this could be a modulator, exciter or channel processor depending on the application).

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2 MXi AMPLIFIER ASSEMBLY

Each MXi Power Amplifier Assembly consists of a control board, fan-cooled heatsink and ten printed circuit board
sub-assemblies. The first module is a pre-amplifier, known as the Front-End Module. Next is the Driver pallet,
which is biased so as to pre-correct for the non-linearity in the final amplifier stage. The next stage is a five-way
splitter that splits the RF power so it can be fed to the PA pallets. The final amplifier stage is the PA pallets. After
the pallets is the five-way combiner which combines the output power from the PA pallets. The last sub-assembly
on the heatsink is the directional coupler which detects the forward and reflected power and provides samples to
the control board and a RF test point on the rear panel. Also mounted on the heatsink is a thermal switch, which
protects the amplifiers from over-temperature conditions such as the absent of cooling or amplifier over
dissipation. Figure 1 below shows the layout of this assembly.

Figure 1 MXi Amplifier Heatsink Assembly

Cooling for the heatsink is provided by a fan array assembly consisting of four 4-inch axial flow +12VDC muffin
fans. This array is situated near the front section of the MXi housing underneath the MXi Amplifier Controller PC
board. The fans blow air into the finned portion of the heatsink, which exhausts through the rear.

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3 MXi AMPLIFIER CONTROLLER

The MXi amplifier control board (Assembly 31C1897) is a single-circuit assembly that provides all of the control
functions required for the MXi series amplifier on a single circuit board. This board can be configured for a number
of different amplifier types, power levels, transmission standards and options.

Figure 2 MXi Controller

The board implements status/telemetry for remote monitoring through a rear panel connector that will interface to
a typical remote control systems (such as Moseley or Gentner). An RS232 serial port is also provided to allow
communication with the main controller located inside the main control chassis. The MXi control board has RF
detectors for forward and reflected power and all the circuitry to support AGC/VSWR/Cutback functions.

For complete documentation regarding the Amplifier Controller, see the publication Amplifier Controller Board.

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4 MAIN CONTROL CHASSIS

The main control chassis located above the RF Amplifiers contains the main control board, LCD touch screen and
RF splitter.

The main control board (Assembly 31C1972) is a single-circuit assembly that provides all of the communications
and controls to the MXi Amplifiers on a single circuit board. The controller uses a RS-232 connection to
communicate with the Amplifiers. The board implements status/telemetry for remote monitoring through a rear
panel connector that will interface to a typical remote control systems (such as Moseley or Gentner). An RS-
232 serial port as well as a RJ45 Ethernet connection is also provided to allow remote monitoring using our In­SiNC Remote Monitoring Software. The MXi control board has RF detectors for forward and reflected power and
all the circuitry to support AGC/VSWR/Cutback functions. For complete documentation regarding the Main
Control Board, see the publication Main Transmitter Controller Board.

On the front panel is the LCD touchscreen. This provides status and telemetry readings for the transmitter. From
the LCD you have the ability to raise or lower the power using AGC controls. You can also enable or disable the
remote controls and setup your Ethernet address or serial stream communications.

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