MXD5U AMPLIFIER TECHNICAL SERVICE MANUAL LARCAN INC. 228 AMBASSADOR DRIVE MISSISSAUGA, ONTARIO CANADA L5T 2J2 PHONE: (905) 564-9222 FAX: (905) 564-9244 EMAIL: techservices@larcan.
MXD5U OPERATIONS AND MAINTENANCE CONTENTS 1 AMPLIFIER ......................................................................................................................................................................1 2 CONTROLLER .................................................................................................................................................................2 2.1 CONTROL BOARD ASSEMBLY AND JUMPER SETTINGS ...............................................................
MXD5U OPERATIONS AND MAINTENANCE FIGURE 8 TEST EQUIPMENT SETUP .............................................................................................................................................14 FIGURE 9 - FRONT END AMPLIFIER, MXD5U.............................................................................................................................16 FIGURE 10 - IPA ASSEMBLY, MXD5U.............................................................................................................
MXD5U OPERATIONS AND MAINTENANCE 1 AMPLIFIER The RF section of the MXD5U Amplifier consists of a heatsink assembly that includes three cascaded broadband amplifier modules and a directional coupler. Figure 1 shows the layout of this assembly. Figure 1 MXD5U Amplifier Heatsink Assembly Also mounted on the heatsink is a thermal switch that protects the amplifier from over temperature conditions.
MXD5U OPERATIONS AND MAINTENANCE 2 CONTROLLER The control board (Assembly 31C1971) is a single-circuit assembly that provides all of the control functions required for the transmitter on a single circuit board. This board can be configured for a number of different transmitter types, power levels, transmission standards and options. Figure 2 Controller Board The control board provides local front panel interface via ON/OFF and RESET buttons.
MXD5U OPERATIONS AND MAINTENANCE E2 Not used in the MXD5U transmitter Setting = no jumper installed E3 Not used in the MXD5U transmitter Setting = no jumper installed E4 Not installed in this assembly E5 Front Panel ON/OFF button Mode This jumper determines the function of the Front Panel ON/OFF button If E5 is in the ‘INT’ position, Remote ON/OFF Controls are disabled, Local Controls Only If E5 is in the ‘EXT’ position, Remote ON/OFF Controls are enabled, Local OFF Control Only More detail on this
MXD5U OPERATIONS AND MAINTENANCE E18 Direct Vswr Relay reset from the Remote Reset Command This jumper allows the Remote Reset Command to directly clear the VSWR trip relay Setting = Installed for all MXD5U transmitters E19 Forward Power Detection Type Setting = PK for all MXD5U transmitters 2.2 POWER CALIBRATION, AGC AND CUTBACK SETUP HIGH VOLTAGE RISK OF EXPOSURE TO VOLTAGES UP TO 260VAC Use particular caution near the power supply’s transformer terminals.
MXD5U OPERATIONS AND MAINTENANCE Turn OFF Amplifier. VSWR Trip With Amplifier OFF, install a short length of cable at the RF output, if one is not already there. Add an N-type Tee connector on the output of the cable. Connect a 50R load on each of the two female connections on the Tee. This results in a 10dB Return Loss for VSWR setup. Ensure E8 is installed. Remove J8 temporarily to prevent cutback. Turn on the Amplifier. Monitor the Reflected Detect port on the Directional Coupler.
MXD5U OPERATIONS AND MAINTENANCE 2.4 EXTERNAL REMOTE CONTROL CONNECTIONS External remote controls are intended to interfacing to a third party remote control vendor such as Moseley or Gentner if such systems are installed or available at the transmitter site. These external controls function in parallel with the serial remote commands implemented with the Larcan supplied remote control program.
MXD5U OPERATIONS AND MAINTENANCE 2.4.3 Remote Status Outputs There are only two remote statuses available to the operator, these being transmitter ON and an Error status. In the table of remote signals, all remote status have a RS_ prefix. The transmitter ON status is a relay contact that with one side of the contact connected to ground. When the transmitter is in the ON state, this relay closes providing a path to ground to the RS_TXON signal.
MXD5U OPERATIONS AND MAINTENANCE RS_TXErr 11 Status, Transmitter Error Ground Reference 12 Ground Reference RT_RflPwr 13 Telemetry, Reflected Power RT_AGC 14 Telemetry, AGC Voltage (1/2 Scale) Ext1+ 15 External Interlock, (+12V Armed) 2.5 EXTERNAL TRANSMITTER INTERLOCK The transmitter provides the customer a set of contacts where an external interlock can be applied to control the ON state of the transmitter.
MXD5U OPERATIONS AND MAINTENANCE 3 AMPLIFIER INSTALLATION AND STARTUP The transmitter can be fully operational with minimal setup when turned ON. However, a good practice is to take the “start from scratch” approach, which means that you should take precautionary measures before the amplifier is allowed to run at full rated power. These important steps will avoid any catastrophic failures at start-up.
MXD5U OPERATIONS AND MAINTENANCE 1. Modulator is Ready. • Usually in the application of AC, the Modulator goes through its warm-up sequence. Ensure that it has done so. 2. CONTROLLER is ready. • If there were prior faults (see front panel LED), clear them by pushing the RESET button. 3. INTERLOCKS are closed or OK. • Interlocks and Status are OK. 4. The TX is OFF. • Push the Front Panel ON/OFF button so that it is NOT pushed in. 3.
MXD5U OPERATIONS AND MAINTENANCE 4 TEST AND TROUBLESHOOTING 4.1 BENCH TEST PROCEDURES The following procedures are test instructions for the amplifier modules comprising the complete amplifier assembly. 4.1.1 Front-End Amplifier (Figure 9) Bench Test Procedure • Connect a +28V (1A current limit) power supply to TP2. • Apply a 0dBm (1mW) RF input to the amplifier. • Turn RV2 fully clockwise. The front-end should have a gain of 13dB.
MXD5U OPERATIONS AND MAINTENANCE • • Before applying +28V to the module, adjust R12 fully clockwise. Limit the power supply current to 3.0A. • Apply +28V to the B+ terminal. Monitor the current and adjust R12 counter clockwise (CCW) for a total current of about 1.0A + 0.05A. • Proceed to the next step if a network analyzer or similar equipment is available. RF SWEEP: Adjust C7 for best frequency response. With the bias set at 1.0A, the gain in the range of 470MHz to 860 MHz should be 15 to 16dB. 4.
MXD5U OPERATIONS AND MAINTENANCE 5 MAINTENANCE Equipment which is regularly and carefully maintained is far less likely to be subject to sudden failure than that which is operated without regard to basic maintenance requirements. A detailed preventive maintenance program should be established to ensure that the original efficiency and picture quality is maintained throughout the life of the equipment.
MXD5U OPERATIONS AND MAINTENANCE 6 TEST EQUIPMENT SETUP Figure 8 Test Equipment Setup PUB09-03 Rev 0 April 16, 2009 09-03-14 MXD5U Operations and Maintenance
MXD5U OPERATIONS AND MAINTENANCE 7 SPECIFICATIONS Specifications are subject to change without notice. 7.1 ELECTRICAL AC Line Input .....................................................................................................................90 to 264VAC, 50 to 60Hz Power Consumption, black picture + 10% aural ................................................................................. 220VA (typical) 7.2 ENVIRONMENTAL Ambient Temperature ....................................................
MXD5U OPERATIONS AND MAINTENANCE Figure 9 - Front End Amplifier, MXD5U PUB09-03 Rev 0 April 16, 2009 09-03-16 MXD5U Operations and Maintenance
MXD5U OPERATIONS AND MAINTENANCE Figure 10 - IPA Assembly, MXD5U PUB09-03 Rev 0 April 16, 2009 09-03-17 MXD5U Operations and Maintenance
MXD5U OPERATIONS AND MAINTENANCE Figure 11 - Amplifier Pallet, MXD5U PUB09-03 Rev 0 April 16, 2009 09-03-18 MXD5U Operations and Maintenance
MXD5U OPERATIONS AND MAINTENANCE Figure 12 MXD5U Control Board Assembly PUB09-03 Rev 0 16 April, 2009 09-13-19 MXD5U Operations and Maintenance
MXD5U OPERATIONS AND MAINTENANCE NOTES PUB09-03 Rev 0 16 April, 2009 MXD5U Operations and Maintenance
