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MXiV DUAL PALLET OPERATIONS AND MAINTENANCE 

4 MAINTENANCE 

4.1 

4.2 

4.3 

4.4 

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. Given reasonable care and attention, the transmitter will provide efficient and reliable service for 
many years. 

Preventive maintenance techniques do not necessarily involve extensive dismantling of the various assemblies; 
on the contrary, this practice is to be discouraged unless a valid reason exists for doing so. Preventive 
maintenance is more directed at detailed physical inspection and the general observation of the equipment during 
and after operation, to detect the presence of any abnormality, which, if not corrected, might result in operational 
failure. 

In preparing any maintenance program, the frequency and scope of the inspections must be determined and to a 
great degree will be influenced by site location and the station's market parameters and consequently its hours of 
operation, equipment configuration, and technical personnel deployment. For example, is the station on the air for 
24 hours-a-day? Are there main/standby transmitters and are they attended or unattended? 

In general, the following routines should form the basis of any maintenance program. 

D

AILY

 

At an attended site, the operator is afforded the opportunity to make frequent checks on the equipment and 
thereby increase his/her familiarity with its operation. The transmitter log entries made during these checks would 
include all meter readings, also any irregularity in performance or in picture quality, for later analysis. An 
unattended site where equipment is operated by remote control and monitored by telemetry and a high quality off-
air receiver or demodulator can also be continuously checked for performance by studio technical personnel. 

M

ONTHLY

 

In addition to the normal operational tests, thorough physical inspection of every piece of equipment should be 
made, with all power turned off. All surfaces should be dusted off or wiped down, terminal boards checked for 
loose connections, and all components examined for any evidence of overheating. High-pressure air, not over 
20psi, can be used with discretion to dislodge dust from inaccessible places. 

S

EMI

-A

NNUALLY AND 

A

NNUALLY

 

Check all external RF connections for tightness, looking specifically for any discoloration, which might indicate a 
loose inner connector, flange or sleeve coupling. Test the passive RF system with a transmission test set or 
network analyzer, if one is available, to identify any potential problems with the antenna or line. Inspect and clean 
contacts on all switches and contactors; carefully redress contact surfaces if pitted. 
Check the operation of all interlocks including patch panel, dummy load, air and thermal switches and emergency 
interlocks (if applicable). 

T

RANSMITTER 

C

OOLING 

S

YSTEM

 

All cooling fans in the transmitter are fitted with sealed bearings requiring no lubrication during the lifetime of the 
motor. Access to the blower assembly is via the top of the transmitter. 

 

 

TSM21Q-365 Rev 0 July 17, 2009 

 

MXiV Dual Pallet Operations and Maintenance 

18

Содержание MXi101V

Страница 1: ...65 MXi101V 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 com TSM21Q 365 Rev 0 July 17 2009 1 ...

Страница 2: ... 2 3 1 Switch to Safety 5 3 LARCAN PARTS ASSEMBLIES ASSEMBLY DRAWINGS AND SCHEMATIC NUMBERS 7 3 1 VENDOR STANDARD PART NUMBERS 7 3 2 LARCAN NUMBERS FOR PARTS ASSEMBLIES AND DOCUMENTATION 7 3 3 LEADED RESISTORS 8 3 4 SURFACE MOUNT RESISTORS 1 4W AND LESS 8 3 5 SURFACE MOUNT CAPACITORS 9 3 6 PARTS LISTS 9 3 6 1 Production Changes 9 FIGURES FIGURE 1 MXI AMPLIFIER HEATSINK ASSEMBLY 3 TSM21Q 365 Rev 0 ...

Страница 3: ... s start up operation and troubleshooting as well as basic transmitter maintenance guidelines The RF section of the MXi101V Amplifier consists of a heatsink assembly that includes three cascaded broadband amplifier modules and a directional coupler Figure 1 shows the layout of an MXi201 assembly The MXi101V utilizes one of these output amplifiers only Figure 1 MXi Amplifier Heatsink Assembly Also ...

Страница 4: ...ody in any manner Avoid cuts by wearing gloves while picking up the broken pieces Be careful do not inhale dust while replacing or emptying vacuum cleaner filter bags and wash your hands thoroughly afterward Wash your hands thoroughly after replacing RF power devices Dispose of defective RF power devices only through approved toxic waste facilities Wear gloves when picking up the pieces Wash your ...

Страница 5: ...Do not try to work on the transmitter if you are tired or drowsy you could make a fatal error in judgment 2 3 1 Switch to Safety Here are some safety suggestions based partially on the knowledge of experts familiar with high powered tubed equipment and partially on the procedures used at a typical utility company and at a company which makes and tests high voltage devices A few of these suggestion...

Страница 6: ...ntrol as well if there is any possibility that a studio worker could unknowingly activate the transmitter while you are working on it One way of ensuring that the lockout placer and remover are the same person is to issue individual padlocks to each person on the transmitter technical staff You might want to include your tower contractor s rigging crew in the list of people who are allowed to use ...

Страница 7: ...g size and Product type Can be 10A 11A 20B 21B 30C 31C 40D 41D 50E 51E describes drawing or document size VHF or UHF application XXXX Drawing Index number Between 0000 to 9999 K Refers to the type of drawing document no suffix for drawing of part assembly or schematic P Part G Group of parts A Assembly drawing F PC board fabrication films and S Schematic n Index number for drawing type Part group ...

Страница 8: ...is 1kΩ 1 4W 5 3 4 SURFACE MOUNT RESISTORS 1 4W AND LESS There is no specified recommended supplier of these parts The Philips numbering system is employed with the following parameters designations example follows 9C A nnnx SIZE LxW POWER RATING RESISTANCE VALUE TOLERANCE TEMP COEF 0603 1 6x08mm 1 1 16W nnx tolerance 5 D 0 5 C 50ppm C nn first 2 digits x multiplier F 1 K 100ppm C 0805 2x1 25mm 2 1...

Страница 9: ...x100000 infrequent use e g 0805CG102J9B SIZE 0805 DIELECTRIC MATERIAL NPO VALUE 1000pF TOLERANCE 5 VOLTAGE RATING 50V TERMINATION Ni Sn PACKAGING Not Specified MARKING None Note that u appears in most cases instead of the correct symbol μ whenever a micro is required Electronic parts list data when imported by our PC publication program allows us to substitute the correct μ when checking and editi...

Страница 10: ...r 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 TSM21Q 365 Rev 0 July 17 2009 MXi101V 10 ...

Страница 11: ...M 18 5 SERVICE 119 5 1 REMOVING THE FAN ARRAY 19 5 2 REPLACING THE ENTIRE FAN ARRAY 20 5 3 REPLACING A SINGLE FAN 20 6 TEST EQUIPMENT SETUP 21 7 SPECIFICATIONS 22 7 1 ELECTRICAL 22 7 2 ENVIRONMENTAL 22 7 3 COOLING 22 7 4 DIMENSIONS 22 7 5 SHIPPING WEIGHT 22 FIGURES FIGURE 2 MXI CONTROLLER 12 FIGURE 3 MXI FRONT PANEL 12 FIGURE 4 MAIN MENU SCREEN 12 FIGURE 5 AMPLIFIER AMP SUBMENU 13 FIGURE 6 REAR PA...

Страница 12: ...ypical remote control systems such as Moseley or Gentner An RS232 serial port is also provided to allow the operator to access the MXi through an external computer with the appropriate software The MXi control board has RF detectors for forward and reflected power and all the circuitry to support AGC VSWR Cutback functions Circuitry to control and monitor the 50V power supply is also included on t...

Страница 13: ... 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 For complete documentation regarding the Controller see the publication MXi Controller Board TSM21Q 365 Rev 0 July 17 2009 MXiV Dual Pallet Operations and Maintenance 13 ...

Страница 14: ...R is recommended Preferably directional couplers with known coupling levels at the frequency of interest should be connected at the input and output of the band pass filter These points are very useful in determining absolute power levels and losses and for use as an RF sample for monitoring purposes See Figure 14 for a typical transmitter test equipment setup 2 Interlocks Interlocks must be conne...

Страница 15: ...iter goes through its warm up sequence Ensure that it has done so 2 POWER METERING is at Zero On the LCD see Main Menu display in Figure 7 the PWR should be at 000 and the STATUS should be TX IS OFF NORMALLY 3 MXi CONTROLLER is ready If there were prior faults clear them by pushing the RESET button 4 INTERLOCKS are closed or OK Interlocks and Status are OK Figure 8 Interlocks Status 5 AGC control ...

Страница 16: ...rmal compensation circuits which reduce the output power when the temperature rises Therefore the operating temperature must be reached before adjusting the RF level to its proper level The amplifier is also equipped with Automatic Gain Control primarily designed to prevent the transmitter from overpower or overdrive condition 3 Increase the RF output by slowly turning the Exciter or Channel Proce...

Страница 17: ... including a complete loss of information on the LCD touchpad In this case replacing the fuse will rectify the problem No RF Output Check for proper power supply voltage Check for potential connector problems causing either no drive to a module pallet input connector or VSWR output connector problems Output Reduced to 25 If the output is approximately 25 a possible cause is a failure of one of the...

Страница 18: ...ke frequent checks on the equipment and thereby increase his her familiarity with its operation The transmitter log entries made during these checks would include all meter readings also any irregularity in performance or in picture quality for later analysis An unattended site where equipment is operated by remote control and monitored by telemetry and a high quality off air receiver or demodulat...

Страница 19: ... plate is secured to the bottom of the MXi chassis with three Phillips head screws Figure 11 Bottom View of MXi 1 Turn the MXi OFF 2 Disconnect the AC power from the MXi 3 Slide the MXi partially out from the mounting rack Important Ensure that the weight of the MXi is fully supported 4 With a Phillips screwdriver remove the three mounting screws on the underside of the MXi When removing the last ...

Страница 20: ...ng plate is fully in place 1 Remove the fan array as described in Section 5 1 9 Replace fan array into MXi as described in Section 5 1 8 If necessary replace the zip tie holding the wires to the fan frame 7 Re fasten the two screw and nut assemblies holding the fan to the mounting plate 6 Re connect the three pin wiring harness connection 5 Remove the defective fan and replace with a known good fa...

Страница 21: ...MXiV DUAL PALLET OPERATIONS AND MAINTENANCE TSM21Q 365 Rev 0 July 17 2009 MXiV Dual Pallet Operations and Maintenance 21 6 Figure 14 Test Equipment Setup TEST EQUIPMENT SETUP ...

Страница 22: ...13 F Humidity 0 to 90 Altitude 2286 m 7500 ft COOLING Four 4 muffin fans push air through the heatsink and through the rear panel perforations DIMENSIONS The Amplifier and Channel Processor chassis are standard 19 rack wide units Height Amplifier 5 25 3RU Exciter or Channel Processor 1 75 1RU Total Height 7 00 4RU Depth is 25 including a 3 allowance for connectors SHIPPING WEIGHT Weight Approximat...

Страница 23: ... MXi AMPLIFIER 24 FIGURES FIGURE 15 FRONT VIEW OF MXI AMPLIFIER 24 FIGURE 16 REAR VIEW OF MXI AMPLIFIER 24 FIGURE 17MXI FAN ARRAY 25 FIGURE 18 MXI HEATSINK ASSEMBLY 25 TSM21Q 365 Rev 0 July 17 2009 MXi Dual Pallet Amplifier Chassis 23 ...

Страница 24: ...o right RF IN SMA connector RF OUT N connector RF TP SMA connector RF sample REMOTE CONTROL 15 pin D shell connector RS232 SERIAL nine pin connector INTERLOCK terminal board AC INPUT The MXi is classified as a broadband amplifier thus it is operational to cover the entire VHF television spectrum in three bands comprising ATSC channels 2 through 4 5 through 6 and channels 7 through 13 Controlled DC...

Страница 25: ...i amplifier The interlock circuit ultimately controls the power supply to the power amplifier and therefore shuts down and remains OFF until the heatsink cools down to about 50 C Figure 18 MXi Heatsink Assembly A directional coupler is also mounted on the heatsink and provides forward and reflected RF signals to the controller These RF samples are detected and processed on the MXi amplifier contro...

Страница 26: ...uly 17 2009 June 2009 26 CONTENTS 1 FUNCTIONAL DESCRIPTION 27 2 RF PREAMPLIFIER 27 3 POWER AMPLIFIER 27 4 ADJUSTMENT OF BIAS VOLTAGE TO ESTABLISH PROPER QUIESCENT FET BIAS CURRENT 28 5 LOW POWER SWEEP AMPLIFIERS 29 FIGURES FIGURE 19 MODULE SWEEP SETUP 29 ...

Страница 27: ...y thermistor elements RT1 and RT2 Bias current is set to 500mA per half of the device for analog operation and 750mA per half for digital operation Gate bias is supplied from an adjustable voltage divider from the 39 V regulated bias rail Resistors R1 R2 R3 R4 provide gate bias for one half of the amplifier R5 R6 R7 R8 provide bias for the other half The RF input signal is applied to balun T1 L1 t...

Страница 28: ... There are 8 fuses in total 2 Adjust all bias pots to maximum resistance for minimum bias voltage Again there are 8 3 3 Use a clip lead to short the junction of C5 R6 and R7 to ground This shuts off side B of the amplifier so it will not interfere thru L9 with measurement of quiescent current from side A 4 Terminate the RF input and output into a 50 Ω load 5 Apply 50VDC from the front panel test p...

Страница 29: ...ep generator should be adjusted to give a linear sweep from 160 to 240 MHz so that all of High Band or Band III is swept with a small amount of out of band signal on both ends 3 Connect the lab power supply 50 V to the positive supply bus bar and the negative to the chassis of the amplifier The current should be limited to 7 or 8 A for this test Caution observe polarity 4 With the power supply swi...

Страница 30: ...Y CONTENTS 1 MXi POWER SUPPLY LAR1000 32 P5337 31 2 POWER SUPPLY DATA SHEET REPRINT 33 FIGURES FIGURE 20 MXI 1000W POWER SUPPLY 31 FIGURE 21 12 TERMINAL INTERFACE BOARD 31 TSM21Q 365 Rev 0 July 17 2009 MXi 1kW Power Supply 30 ...

Страница 31: ...et power level This unit also contains an internal auxiliary 12VDC power supply rated at 3A which is used to provide power to the MXi Controller board as well as supplying power to the cooling fans This auxiliary power supply provides 12VDC output as long as the main AC input is present Figure 20 MXi 1000W Power Supply A 12 terminal interface board is used in the power supply for interfacing to va...

Страница 32: ... 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 12V ENABLE INPUT If 12V is applied here it will turn ON the 50VDC power supply This enable signal comes from the MXi controller board provided the interlocks are closed and there are no fault conditions 8 NOT USED 9 NOT USED 10 GND AC GND 11 N AC Neutral 1...

Страница 33: ...ER 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 TSM21Q 365 Rev 0 July 17 2009 MXi101V 33 ...

Страница 34: ...MXi 50V 1KW POWER SUPPLY TSM21Q 365 Rev 0 July 17 2009 MXi101V 34 ...

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