Ericsson MGM 450 Maintenance Manual Download Page 49 | Manualshive

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Summary of Contents for MGM 450

Page 1: ...ericssonz LBI 38865A Maintenance Manual Monogram Series UHF MOBILE RADIO MODEL MGM 450 ...

Page 2: ...hout the express written permission of Ericsson Inc Copyright November 1994 Ericsson Inc NOTICE The software contained in this device is copyrighted by Ericsson Inc Unpublished rights are reserved under the copyright laws of the United States NOTE Repairs to this equipment should be made only by an authorized service technician or facility designated by the supplier Any repairs alterations or subs...

Page 3: ...BOTTOM COVERS 15 FRONT PANEL 15 RF BOARD 15 DIGITAL BOARD 16 PROGRAMMING INSTRUCTION 17 TEST EQUIPMENT SETUP 18 ALIGNMENT PROCEDURE 19 22 SUGGESTED TEST EQUIPMENT 19 PROGRAMMING FOR ALIGNMENT 19 PLL ALIGNMENT 20 TRANSMITTER ALIGNMENT 20 RECEIVER ALIGNMENT 22 RF BOARD ALIGNMENT AND TEST POINTS 24 DIGITAL BOARD ALIGNMENT AND TEST POINTS 25 PERFORMANCE TEST 26 27 TRANSMITTER PERFORMANCE TEST 26 RECEI...

Page 4: ...VIEW 406136 F ISSUE H RF BOARD 32 2 TOP VIEW 406137 E ISSUE H DIGITAL BOARD 32 3 BOTTOM VIEW 406137 E ISSUE H DIGITAL BOARD 32 4 MISC PRINTED CIRCUIT BOARDS 32 5 MISC PRINTED CIRCUIT BOARDS 32 6 EXPLODED VIEW AND PARTS LIST 33 SCHEMATICS 34 MONOGRAM SERIES LBI 38865 TABLE OF CONTENTS Page iv Nov 94 ...

Page 5: ...rain Standby 0 15 Amp Receive 0 5 Amp Transmit 8 Amp Temperature Range 30 to 60 C Dimensions 2 x 6 x 8 25 inches 51 x 152 x 210 mm Weight 4 lbs 3 oz 1 9kg With Mic FCC Compliance Parts 15 22 74 90 95 FCC ID Designation 400 440 MHz F3JSM445A 450 470 MHz F3JSM445C 470 512 MHz F3JSM445E DOC Canada Type Approval 400 440 MHz N A 450 470 MHz 287194100I 470 512 MHz N A MONOGRAM SERIES LBI 38865 SPECIFICA...

Page 6: ...70 dB Audio Power Output 5 W 10 Dist into 40 W Load Frequency Stability 0 0005 Operational Bandwidth 10 mHz 3dB degradation at band limits Frequency Spread Band Width Factory Programmed Freq Spreads 400 440 MHz 10 MHz 405 415 MHz 3 dB Degradation at limits 450 470 MHz 10 MHz 460 470 MHz 3 dB Degradation at limits 470 512 MHz 10 Mhz 500 510 MHz 3 dB Degradation at limits UHF PROGRAMMING CHART RECEI...

Page 7: ...quency Stability 0 0005 Operational Bandwidth 20 mHz 3dB degradation at band limits Frequency Spread Band Width Factory Programmed Freq Spreads 400 440 MHz 20 MHz 405 420 MHz 3 dB Degradation at limits 450 470 MHz 20 MHz 450 470 MHz 3 dB Degradation at limits 470 512 MHz 20 Mhz 490 510 MHz 3 dB Degradation at limits UHF PROGRAMMING CHART TRANSMIT MONOGRAM SERIES LBI 38865 SPECIFICATIONS Page 3 Nov...

Page 8: ...IES CONTROL STATION OPTIONS NOTSHOWN Antenna MGAN1A Relay Kit MGSU1C Noise Suppression Kit MGPD1A Power Supply MGPS5V External Speaker MGZM7C Desk Microphone MGMC5H MONOGRAM SERIES LBI 38865 SPECIFICATIONS Page 4 Nov 94 ...

Page 9: ...g material carefully for the following items 1 Transceiver Unit 2 Microphone 3 DC power cord 4 Mobile Mounting Bracket 5 Assembly Hardware 6 Operating Guide Styrofoam not used Inner Packing is now cardboard tray box MONOGRAM SERIES LBI 38865 UNPACKING Page 5 Nov 94 ...

Page 10: ...croprocessor Control Synthesized RF Channel selection frequency control Vacuum Fluorescent Channel Selection Display Channel Guard CTCSS Encode Decode Digital channel Guard DCG Encode Decode Priority Scan 5 PPM frequency stability Field Programmable with PC Variable Squelch Internal 5 watt Speaker with volume control Side Mounted Microphone Connector Rear Mounted Antenna Connector SO 239 Rear powe...

Page 11: ... SCAN Push Button P This button turns the PRIORITY SCAN function ON indicated by a red backlight and OFF It also provides access to the programming mode when the radio is turned on 7 Channel Change buttons CH The channel change buttons allow the operator to scroll either up or down through the programmed channels 8 Call Light Indicator CALL This green Light Emitting Diode LED indicator illuminates...

Page 12: ...2 Auxiliary Speaker Connector This 3 5mm diameter jack is provided for an auxiliary speaker Option MGSU1C Relay Kit is required 3 Antenna Connector An SO 239 type connector The output load must be 50 ohms 4 DC 13 8V Connector Polarized plug for 13 8 VDC power input FOR NEGATIVE GROUND SYSTEMS ONLY FIGURE 3 Back Panel Controls MONOGRAM SERIES LBI 38865 DESCRIPTION OF CONTROLS Page 8 Nov 94 ...

Page 13: ...sary to illuminate it s backlight Adjust the volume control to a comfortable listening level 3 Rotate the SQUELCH control clockwise until the squelch noise rushing sound is no longer present 4 Depress the MONITOR button 2 to extinguish the blacklight NOTE If the radio is equipped with coded squelch options depress the MONITOR button 2 to enable the option the CALL indicator will no longer be illum...

Page 14: ...at Channel Guard is programmed and disabled Table 1 Channel Guard tone Frequencies Standard Tone Frequencies in Hertz 67 0 71 9 74 4 77 0 79 7 82 5 85 4 88 5 91 5 94 8 97 4 100 0 103 5 107 2 110 9 114 8 118 8 123 0 127 3 131 8 136 5 141 3 146 2 151 4 156 7 162 2 167 9 173 8 179 9 186 2 192 8 203 5 210 7 218 1 225 7 233 6 241 8 250 3 Table 2 Primary DCS Codes DIGITAL SQUELCH CODES 023 114 174 266 4...

Page 15: ...fore being supplied to the drain of Q2 The difference frequency signal at 21 4 MHz exits the mixer at the source of Q2 and is tuned for 21 4 MHz by T8 which drives the first IF filter XF1 and XF2 XF1 and XF2 form a 4 pole monolithic crystal filter pair which in part determines the selectivity of the radio The output of the crystal filter is routed to the first IF amplifier formed around Q3 RF tran...

Page 16: ... automatic power control The carrier signal passes through the automatic power control directional coupler the RF output lowpass filter and then is routed to the antenna connector Automatic Power Control The automatic power control directional coupler samples a portion of the forward RF power output to determine the RF level Diode D15 rectifies this RF sample and produces a DC voltage which is pro...

Page 17: ...tate of IC118 pin 6 This produces a lower frequency which can be further divided by IC108 By strategic timing when to divide by 128 or 129 the overall division will be that necessary to put the VCO on the correct frequency Loop Filter Resistors R317 through R322 and capacitors C291 C294 and C295 form the loop filter The purpose of the loop filter is to filter out the 6 25 kHz reference frequency p...

Page 18: ...ation limits Over voltage is indicated when the battery loses water rapidly Usage of 1 or 2 ounces of water per cell per week is acceptable for batteries in continuous operation A weak battery will often cause excessive noise or faulty operation MECHANICALINSPECTION Since mobile units are subject to constant shock and vibration check for loose plugs nuts screws and other parts to make sure that no...

Page 19: ...digital board A ribbon cable from the display board to the digital board must be unplugged to remove front panel RFBOARD 1 Remove the 13 M3 x 24 machines screws securing the RF shield to the chassis 2 Remove the M3 x 8 machine screw that secures the DC cord bracket to the chassis Slide the bracket and cord out of the chassis 3 Remove the 6 M3 x 6 machine screws 3 on top and 3 on bottom that secure...

Page 20: ...ket to the chassis Slide the bracket and cord out of the chassis 6 Remove the RF shield by pushing the front panel forward so the shield will clear and then sliding the DC cord bracket and connector through the rectangular hole in the shield 7 Unplug the VCO cable from the jack 8 Remove the remaining 10 screws securing the digital board IC5 IC6 and IC104 to the chassis 9 The digital board can now ...

Page 21: ... the radio To use this cable remove the top cover of the radio as described in the DISASSEMBLY section Plug the six pin connector into the socket inside the radio PL1 which is located near the EEPROM IC107 Plug the base of the Y into the computer that will program the radio See the diagram in TQ 3375 Software Manual In order to program the radio with the programming cable it is necessary to put th...

Page 22: ...TEST EQUIPMENT SETUP OPTIONAL TEST EQ MONOGRAM SERIES LBI 38865 TEST EQUIPMENT SETUP Page 18 Nov 94 ...

Page 23: ...RAMMINGFORALIGNMENT For the alignment procedures the EEPROM should be programmed as follows 1 An EEPROM should be programmed with 3 transmit and 3 receive frequencies 2 The lowest and highest frequencies should enclose the user s frequencies and be 10 MHz apart The lowest and highest frequencies must be within the appropriate frequency band 3 In addition to programming frequencies CTCSS and DCS co...

Page 24: ...ead less than 7 5 volts 7 Release the PTT switch CHANNEL TP1 VOLTAGE TRANSMIT RECEIVE Lowest Frequency 1 5 VDC 2 0 VDC Highest Frequency 7 5 VDC 7 0 VDC TRANSMITTERALIGNMENT 1 Connect a 50 ohm RF dummy load or a power attenuator 50 watt minimum rating through a watt meter 50 watt scale to the antenna receptacle 2 Turn RV2 Automatic power adjustment fully clockwise 3 Connect variable DC power suppl...

Page 25: ...o prevent damage to the deviation meter 3 Press the PTT switch 4 Observe the waveform on the oscilloscope and compare with that shown in Figure 6 5 Adjust RV5 and TC12 to achieve the proper wave form Release the PTT switch 6 Replace the deviation meter with a frequency counter 7 Set the CHANNEL selector to the highest transmit channel Ensure that this channel has no DCS or CTCSS tones pre programm...

Page 26: ... for the 4 2 kHz deviation if no CTCSS tones are present and 4 9 kHz deviation if CTCSS tones are present RECEIVERALIGNMENT 1 Connect an RF signal generator or communications service monitor to the antenna receptacle 2 Connect a SINAD meter and an audio distortion analyzer across the speaker terminals If an audio distortion analyzer is not available connect an oscilloscope across the speaker termi...

Page 27: ...nimum 3 Adjust the SQUELCH control to the threshold point the point where the speaker audio disappears 4 Increase the RF signal generator output level until speaker audio output reappears Note the generator level 5 Turn the SQUELCH control fully clockwise 6 Increase the RF signal generator level by 16 dB NOTE This squelch adjustment procedure is very important for the correct operation of the micr...

Page 28: ...RF BOARD ALIGNMENT AND TEST POINTS MONOGRAM SERIES LBI 38865 RF BOARD ALIGNMENT AND TEST POINTS Page 24 Nov 94 ...

Page 29: ...DIGITAL BOARD ALIGNMENT AND TEST POINTS MONOGRAM SERIES LBI 38865 DIGITAL BOARD ALIGNMENT AND TEST POINTS Page 25 Nov 94 ...

Page 30: ... audio generator level to produce 1 kHz deviation 5 Set the audio generator frequency to 2 kHz The transmitter deviation should be approximately 2 kHz 6 As the audio generator frequency is varied from 300Hz to 10 kHz the deviation should increase until it reaches a maximum at an audio frequency of 2 5 kHz to 2 9 kHz At higher frequencies the deviation should decrease the deviation at an audio freq...

Page 31: ...unication service monitor connected to the radio adjust the VOLUME control to obtain a noise reading of 1 volt RMS on the VOM 4 Connect the RF signal generator or service monitor to the radio Set the RF frequency to the receiver frequency of radio and remove any modulation 5 Adjust the signal generator RF level for a noise reading on the VOM of 0 1 volt RMS This is the 20 dB noise quieting point t...

Page 32: ...o distortion analyzer may include this function to the speaker leads 4 With a 3 kHz deviation of a 1 kHz tone modulation applied to the signal generator rotate the VOLUME control clockwise until the audio distortion is 10 or until the VOLUME controls reaches stop whichever comes first 5 The audio voltmeter should read 4 0 volts or greater MONOGRAM SERIES LBI 38865 PERFORMANCE TEST Page 28 Nov 94 ...

Page 33: ...rface mount component with the soldering iron If a hot air system is used direct the heat to the terminals of the component Use extreme care with the soldering equipment to prevent damage to the printed circuit board PCB and the surrounding components 3 When the solder on all terminals is liquefied gently remove the component Excessive force may cause the PCB pads to separate from the board if all...

Page 34: ...stem is the best method of replacing surface mount IC s can easily be removed and installed using the hot air system See the manufacturers instructions for complete details on tip selection and other operating instructions unique to your system If a hot air system is not available the service technician may wish to clip the pins near the body of the defective IC and remove it the pins can then be ...

Page 35: ...those items indicated by shading will be stocked by After Market Services All other items are for reference only When ordering parts for your Monogram Series radio precede all part numbers with the prefix R29 NOTE Page 31 Nov 94 ...

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Page 53: ...PRINTED CIRCUIT BOARD LAYOUT Page 32 Nov 94 ...

Page 54: ...TOP VIEW 406136 E RF BOARD MONOGRAM SERIES LBI 38865 TOP VIEW 406136 E RF BOARD Page 32 1 Nov 94 ...

Page 55: ...BOTTOM VIEW 406136 E RF BOARD MONOGRAM SERIES LBI 38865 BOTTOM VIEW 406136 E RF BOARD Page 32 2 Nov 94 ...

Page 56: ...TOP VIEW 406137 E DIGITAL BOARD MONOGRAM SERIES LBI 38865 TOP VIEW 406137 E DIGITAL BOARD Page 32 3 Nov 94 ...

Page 57: ...BOTTOM VIEW 406137 E DIGITAL BOARD MONOGRAM SERIES LBI 38865 BOTTOM VIEW 406137 E DIGITAL BOARD Page 32 4 Nov 94 ...

Page 58: ...MISC PRINTED CIRCUIT BOARDS DISPLAY BOARD BOTTOM VIEW DISPLAY BOARD TOP VIEW VOLUME BOARD BOTTOM VIEW VOLUME BOARD TOP VIEW MONOGRAM SERIES LBI 38865 MISC PRINTED CIRCUIT BOARDS Page 32 5 Nov 94 ...

Page 59: ...ED CIRCUIT BOARDS 406 968 C RF PCB TOP 406 968 C RF PCB BOTTOM 406 973 A TOP 406 973 A BOTTOM 406 969 F DIG PCB TOP 406 969 F DIG PCB BOTTOM MONOGRAM SERIES LBI 38865 MISC PRINTED CIRCUIT BOARDS Page 32 6 Nov 94 ...

Page 60: ...VOLTAGE CHARTS MONOGRAM SERIES LBI 38865 VOLTAGE CHARTS Page 32 7 Nov 94 ...

Page 61: ...VOLTAGE CHARTS MONOGRAM SERIES LBI 38865 VOLTAGE CHARTS Page 32 8 Nov 94 ...

Page 62: ...VOLTAGE CHARTS MONOGRAM SERIES LBI 38865 VOLTAGE CHARTS Page 32 9 Nov 94 ...

Page 63: ...MONOGRAM SERIES LBI 38865 VOLTAGE CHARTS Page 32 10 Nov 94 ...

Page 64: ... LIST Only those items indicated by shading will be stocked by After Market Services All other items are for reference only When ordering parts for your Monogram Series radio precede all part numbers with the prefix R29 NOTE Page 33 Nov 94 ...

Page 65: ...MONOGRAM SERIES LBI 38865 Page 33 1 Nov 94 ...

Page 66: ...MONOGRAM SERIES LBI 38865 Page 33 2 Nov 94 ...

Page 67: ...MONOGRAM SERIES LBI 38865 Page 33 3 Nov 94 ...

Page 68: ...SCHEMATICS Ericsson Inc Private Radio Systems Mountain View Road Lynchburg Virginia 24502 1 800 528 7711 Outside USA 804 528 7711 Printed in U S A Page 34 Nov 94 ...

Page 69: ...RF BOARD R29 406136 E LBI 38865 34 1 ...

Page 70: ...DIGITAL BOARD R29 406137 E LBI 38865 34 2 ...

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