TSM21Q-365 MXi201V 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.
MXi201V TECHNICAL SERVICE MANUAL CONTENTS TSM20-365 MXi201U TECHNICAL SERVICE MANUAL 1 MXi201U AMPLIFIER–INTRODUCTION ..................................................................................................................3 2 SAFETY NOTICES..........................................................................................................................................................4 2.1 BERYLLIUM OXIDE WARNING ..........................................................................
MXi201V TECHNICAL SERVICE MANUAL 1 MXi201V AMPLIFIER–INTRODUCTION This Technical Service Manual contains publications (PUBs) describing the technical details of the MXi201V amplifier, as well as the overall operating instructions, including the bench test procedures of the amplifier stages incorporated in this unit. It also covers the transmitter’s start-up operation, and troubleshooting, as well as basic transmitter maintenance guidelines.
MXi201V TECHNICAL SERVICE MANUAL 2 SAFETY NOTICES This section provides general guidance and information for the operation, maintenance, and service personnel who are familiar with the hazards of working with high-powered electronic circuits. This manual does not detail all of the safety precautions which should be observed when servicing this or any other electronic equipment.
MXi201V TECHNICAL SERVICE MANUAL Rule #1 KILL THE AC POWER BEFORE IT KILLS YOU Under no circumstances should any person reach within the cabinets for the purpose of servicing or adjusting the equipment without first disconnecting the AC power or without the immediate presence of another person capable of rendering aid. The “buddy” system is encouraged for transmitter work. Rule #2 DO NOT TAMPER WITH INTERLOCKS OR SAFETY SHIELDS Under normal circumstances, no safety shield should be removed.
MXi201V TECHNICAL SERVICE MANUAL Avoid wearing loose clothing and personal jewelry such as rings, watches, and chains when working near energized circuits. Make a habit of removing all jewelry and storing it in a safe place as soon as you enter the transmitter building. Before beginning work, shut off all AC to the transmitter power supplies. Tag and lockout the switches.
MXi201V TECHNICAL SERVICE MANUAL 3 LARCAN PARTS, ASSEMBLIES, ASSEMBLY DRAWINGS AND SCHEMATIC NUMBERS 3.1 VENDOR STANDARD PART NUMBERS Vendor or original manufacturer part numbers are indicated for most components. 3.
MXi201V TECHNICAL SERVICE MANUAL 3.3 LEADED RESISTORS Generic carbon composition resistors with leads are numbered as follows: nnnx 3R P - or - nnx Power Rating Resistance Value * 152 = 1/4W nn - 77 = 1/2W Tolerance first digits of K =10% resistance (5, 10% tol.) 78 = 1W nnn - 79 = 2W resistance (1% tol.) J =5% first digits of H =1% x - x10 multiplier For values between 1Ω and 10Ω, a letter “R” will appear in the resistance value to indicate the decimal place.
MXi201V TECHNICAL SERVICE MANUAL Example: 9C08052A1001FK (Size 0805, Power Rating 1/10W, Resistance 1kohm, Tolerance 1%, Temperature Coefficient 100ppm/°C) 3.5 SURFACE MOUNT CAPACITORS There is no specifically recommended supplier of these parts.
MXi201V TECHNICAL SERVICE MANUAL A revision letter or number may follow the model or group number marked on the nameplate, chassis, or circuit board; or on the parts list (where it is an "R" followed by a dash and a number). Whenever a revision letter or number appears, it should be quoted in any communication regarding the equipment.
MXiV DUAL PALLET OPERATIONS AND MAINTENANCE CONTENTS 1 MXi CONTROLLER .....................................................................................................................................................12 2 AMPLIFIER INSTALLATION AND STARTUP .......................................................................................................14 2.1 BEFORE APPLYING AC TO THE UNIT ............................................................................................................
MXiV DUAL PALLET OPERATIONS AND MAINTENANCE 1 MXi CONTROLLER The MXi control board (Assembly 31C1897) is a single-circuit assembly that provides all of the control functions required for the MXi series of transmitters on a single circuit board. This board can be configured for a number of different transmitter types, power levels, transmission standards and options.
MXiV DUAL PALLET OPERATIONS AND MAINTENANCE Forward (FWD) and Reflected power (RFL), AURal power, AGC and CUTBack (VSWR) control voltage, as well as the heatsink TEMPerature (Optional) can be displayed by selecting the AMP submenu as shown in Figure 5. Figure 5 Amplifier (AMP) Submenu Similarly, pressing the power supply P/S submenu from the Main Menu displays the power supply voltage and current consumption as well as its status.
MXiV DUAL PALLET OPERATIONS AND MAINTENANCE 2 AMPLIFIER INSTALLATION AND STARTUP The MXi Amplifier was fully tested at LARCAN before it was delivered. Under normal circumstances, 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.
MXiV DUAL PALLET OPERATIONS AND MAINTENANCE Figure 7 Main Menu 2.3 BEFORE TURNING THE AMPLIFIER ON From the Main Menu, the status of the amplifier is displayed and shows if the amplifier is ready for operation. Status legends, when lit, such as the INTK (INTERLOCK), usually signify OK conditions and that the transmitter is ready to be turned ON. Check that all of the following conditions are met: 1. EXCITER or Channel Processor is Ready. • 2. POWER METERING is at Zero. • 3.
MXiV DUAL PALLET OPERATIONS AND MAINTENANCE • Push the Front Panel ON/OFF button so that it is NOT pushed in. 2.4 AMPLIFIER ON SEQUENCE Upon depressing the ON button, the fans start and at the same time the +50V power supply is enabled, thus applying power to the MXi Amplifier. Since the Exciter or Channel Processor is on hot standby (RF is always applied), the amplifier normally produces output power immediately. 2.4.1 Turning ON MXi Amplifier 1.
MXiV DUAL PALLET OPERATIONS AND MAINTENANCE 3 TEST AND TROUBLESHOOTING 3.1 BASIC TROUBLESHOOTING TECHNIQUES One of the best tools in troubleshooting is knowing what the nominal figures or typical values of the MXi amplifier when it is at its normal performance. If a fault condition occurs, then you can compare the data taken previously with the present conditions and come up with a reasonable conclusion about what is at fault. The following describes some fault conditions and possible solutions. 3.1.
MXiV DUAL PALLET OPERATIONS AND MAINTENANCE 4 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.
MXiV DUAL PALLET OPERATIONS AND MAINTENANCE 5 SERVICE The MXi contains few user-serviceable parts; the modular surface-mount design makes module replacement and/or factory repair the most efficient repair method. The service most likely to be performed by users is the replacement of the fan array. 5.1 REMOVING THE FAN ARRAY The MXi fan array consists of four 4” muffin-type fans which are attached to the mounting plate.
MXiV DUAL PALLET OPERATIONS AND MAINTENANCE Figure 12 Fan Array 5.2 REPLACING THE ENTIRE FAN ARRAY In the event of a fan failure, LARCAN recommends replacing the entire array, as all fans have a similar lifespan. 1. Remove the fan array as described in Section 5.1. 2. Slide the new fan array into the MXi. The power connection is aligned so that it connects when the mounting plate is fully in place. 3. Insert and tighten the five mounting screws. Note: Screws only need to be snug; do not overtighten. 5.
MXiV DUAL PALLET OPERATIONS AND MAINTENANCE 6 TEST EQUIPMENT SETUP Figure 14 Test Equipment Setup TSM21Q-365 Rev 0 July 17, 2009 21 MXiV Dual Pallet Operations and Maintenance
MXi DUAL PALLET 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 ................................................................................. 500VA (typical) 7.2 ENVIRONMENTAL Ambient Temperature ..........................................
MXi DUAL PALLET AMPLIFIER CHASSIS CONTENTS 1 MXi DUAL PALLET AMPLIFIER...............................................................................................................................24 FIGURES FIGURE 15 FRONT VIEW OF MXI AMPLIFIER ..............................................................................................................................24 FIGURE 16 REAR VIEW OF MXI AMPLIFIER .................................................................................................
MXi DUAL PALLET AMPLIFIER CHASSIS 1 MXi DUAL PALLET VHF AMPLIFIER The MXi Dual Pallet VHF Amplifier Chassis Assembly consists of a standard 19" rack mountable 5.25" (3RU) enclosure containing the amplifier heatsink assembly, a fan array assembly consisting of four DC cooling fans, a controller board with built-in RF detectors, and a front panel consisting of ON/OFF, RESET switches and an LCD/Touchpad, and a rear panel assembly with connectors for interfacing to external equipment.
MXi DUAL PALLET AMPLIFIER CHASSIS push air from the front panel through the heatsink and through the perforations in the rear panel. This assembly is located underneath the MXi Controller board. Figure 17 MXi Fan Array A thermal switch is mounted on the heatsink where the operating temperature is sensed. If this temperature increases beyond the trip point of the thermal switch, which is about 60°C, its contact opens and breaks the interlocking circuit of the MXi amplifier.
POWER AMPLIFIER HEATSINK ASSEMBLY CONTENTS 1 FUNCTIONAL DESCRIPTION:...................................................................................................................................27 2 RF PREAMPLIFIER ......................................................................................................................................................27 3 POWER AMPLIFIER: ..................................................................................................................
POWER AMPLIFIER HEATSINK ASSEMBLY 1 FUNCTIONAL DESCRIPTION: The Power Amplifier heatsink assembly consists of a preamplifier driving a four-way power splitter, four 250W FET amplifiers, a four-way power combiner. A full-size heatsink provides the cooling for the active devices. It is designed for High Band 174 - 230 MHz television systems, and provides power gain of approximately 15 - 16 dB, with 1 kW peak sync visual or 600 W aural output.
POWER AMPLIFIER HEATSINK ASSEMBLY operating frequency band, also is equivalent to a dead short at lower frequencies where it loads the device so heavily so that the stage will not become unstable. Note that fuses are provided for the voltage supplied to the FET drain connections. The intent of these fuses is to protect the surrounding circuitry in the event of a device failure.
POWER AMPLIFIER HEATSINK ASSEMBLY 6 LOW POWER SWEEP AMPLIFIERS Note: Low power sweep of PA modules should not be required under normal circumstances – even when replacing FET devices. There are no tuning adjustments on these modules. 1. Ensure that terminations are in place in the test setup. All modules require 50 Ω source and load impedances to prevent damage and for consistent results during testing. 2. Connect the module to a sweep system, typically as shown in Figure 1.
MXi 50V 1KW POWER SUPPLY CONTENTS 1 MXi POWER SUPPLY LAR1000-32-P5337.................................................................................................................31 2 POWER SUPPLY DATA SHEET REPRINT ..............................................................................................................33 FIGURES FIGURE 20 MXI 1000W POWER SUPPLY ....................................................................................................................................
MXi 50V 1KW POWER SUPPLY 1 MXi POWER SUPPLY LAR1000-50-P5337 The LAR1000-50-P5337 power supply used in the MXi Dual Pallet VHF amplifier is a free-standing, power factor corrected 1000W unit. It has the capability to deliver up to 20A when the power supply output is set to +50VDC. The design of this unit results in a highly efficient power supply ideal for the MXi dual pallet power level.
MXi 50V 1KW POWER SUPPLY TERMINAL/DESCRIPTION FUNCTION 1. +50VDC OUTPUT First of two +50VDC outputs of the power supply 2. +50VDC OUTPUT Second of two +50VDC outputs of the power supply 3. COMMON (–) return of the 50V and 12V power supply 4. COMMON (–) return of the 50V and 12V power supply 5. +12VDC OUTPUT +12VDC for powering the MXi controller 6. POWER GOOD A High (+12V) is measured here if the +50V power supply is OK 7.
MXi 50V 1KW POWER SUPPLY 2 POWER SUPPLY DATA SHEET REPRINT The following is a reprint of the LAR1000-50-P5337 switching power supply data sheet, with permission from Absopulse Electronics Ltd.
MXi 50V 1KW POWER SUPPLY TSM21Q-365 Rev 0 July 17, 2009 34 MXi201V
