Related Manuals for GE MLSH041
Summary of Contents for GE MLSH041
- Page 1 LBI-38438A Maintenance Manual Service Section MLS High-Band Two-Way Mobile Radios MLSH041...
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Page 2: General Information
GENERAL INFORMATION NOTICE! Repairs to this equipment should be made only by an authorized service technician or facility designated by the supplier. Any repairs, alterations or substitution of recommended parts made by the user to this equipment not approved by the manufacturer could void the user's authority to operate the equipment in addition to the manufacturer's warranty. -
Page 3: Table Of Contents
TABLE OF CONTENTS DESCRIPTION ............................4 INITIAL ADJUSTMENT........................4 TRANSMITTER ADJUSTMENT....................4 RECEIVER ADJUSTMENT .......................4 RE-INSTALLATION ........................4 MAINTENANCE .............................5 PREVENTIVE MAINTENANCE....................5 3.1.1 Connections ........................5 3.1.2 Electrical System ......................5 3.1.3 Mechanical Inspection ....................5 3.1.4 Antenna..........................5 3.1.5 Alignment ........................5 3.1.6 Frequency Check ......................5 3.1.7 Disassembly........................5 PA TRANSISTOR REPLACEMENT ..................6 CHIP COMPONENT REPLACEMENT..................7 3.3.1... -
Page 4: Description
DESCRIPTION 1 DESCRIPTION The service section contains the information necessary for aligning and troubleshooting the MLS two-way FM mobile radio. In addition, information is provided for removing and replacing chip components, disassembly procedures and module replacement procedures. 2 INITIAL ADJUSTMENT After the radio has been installed as described in the Installation Manual, the following adjustments should be made by a certified electronics technician. -
Page 5: Maintenance
MAINTENANCE 3 MAINTENANCE PREVENTIVE MAINTENANCE To insure high operating efficiency and to prevent mechanical and electrical failures from interrupting system operations, routine checks should be made of all mechanical and electrical parts at regular intervals. Preventive maintenance should include checks detailed in the following sections. -
Page 6: Pa Transistor Replacement
MAINTENANCE The PA transistor contains Beryllium Oxide, a TOXIC substance. If the ceramic or other encapsulation is opened, crushed, broken or abraded, the escaping dust may be hazardous if inhaled. Use care when replacing the module. WARNING PA TRANSISTOR REPLACEMENT 1. -
Page 7: Chip Component Replacement
MAINTENANCE CHIP COMPONENT REPLACEMENT Replacement of chip capacitors should always be done with a temperature controlled soldering iron, using a controlled temperature of 700ºF (371º C). However, do NOT touch black metal film of the resistors or the ceramic body of capacitors with the soldering iron. -
Page 8: Disassembly Procedure
DISASSEMBLY PROCEDURE 4 DISASSEMBLY PROCEDURE TO REMOVE THE SYSTEM CONTROL/SYNTHESIZER BOARD 1. Remove the two (2) screws (A) securing the top cover (refer to Figure 2). Remove the top cover. Then disconnect the interconnecting cables. 2. Remove the eight (8) screws (B) securing the Synthesizer shield. Remove the shield. 3. - Page 9 DISASSEMBLY PROCEDURES Figure 2 – Disassembly Procedure (Top View) Figure 3 – Disassembly Procedure (Bottom View) LBI-38438A...
- Page 10 DISASSEMBLY PROCEDURE Figure 4 – Disassembly Procedure (Front Panel) LBI-38438A...
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Page 11: Alignment And Troubleshooting Procedures
ALIGNMENT AND TROUBLESHOOTING PROCEDURES 5 ALIGNMENT AND TROUBLESHOOTING PROCEDURES Radio maintenance is facilitated by using the Troubleshooting Procedures and servicing techniques unique to this radio. The Troubleshooting Procedures are designed to lead the serviceman rapidly to the defective component or circuit. Troubleshooting procedures are provided for most major problems that might arise in the Transmitter, the Receiver, and the System Control/Synthesizer Board. -
Page 12: Tx Vco & Rx Vco Alignment
ALIGNMENT AND TROUBLESHOOTING PROCEDURES 5.1.2 TX VCO & RX VCO Alignment CMC-232A 29.7 - 42 MHz METERING TUNING METER STEP POINT CONTROL READING PROCEDURE TP201 L206 4.0 VDC In case highest transmit frequency is Control < 34.0 MHz. Select lowest frequency Voltage transmit channel. -
Page 13: Transmitter Frequency Adjustment
ALIGNMENT AND TROUBLESHOOTING PROCEDURES METERING TUNING METER STEP POINT CONTROL READING PROCEDURE TP201 L206 7.0 VDC Select highest frequency transmit Control channel. With 50 ohm load on the Voltage antenna connector J1, key the radio. Monitor Monitor TP201 with digital voltmeter and tune L206 for 7.0 VDC ±0.1 V. -
Page 14: Audio Check
ALIGNMENT AND TROUBLESHOOTING PROCEDURES 3. Connect the audio oscillator and apply a 1 kHz tone at 850 mVrms to MIC HI, J701- 4. Connect the deviation monitor to the antenna connector, J1 through a 30 dB decoupler. Key the radio. Set DEV ADJUST, RV201 for ±3.75 kHz deviation. 4. -
Page 15: Audio Output Level Adjustment Procedure
ALIGNMENT AND TROUBLESHOOTING PROCEDURES 5.1.7 Audio Output Level Adjustment Procedure METERING TUNING METER STEP POINT CONTROL READING PROCEDURE Set the signal generator to the receiver J701-1 RV601 frequency with ±3 kHz deviation and 1 kHz Procedure modulation. Set the RF signal level to 1000 microvolts. -
Page 16: Transmitter
ALIGNMENT AND TROUBLESHOOTING PROCEDURES TRANSMITTER Alignment and troubleshooting for Transmitter circuitry on the Transmitter/Receiver board CMN-233A/B. 5.2.1 General Description Of Adjustment This manual is prepared for adjustments and confirmations of the Exciter/PA section and covers the following items. 5.2.2 Measuring Instruments 1. -
Page 17: Adjustment System
ALIGNMENT AND TROUBLESHOOTING PROCEDURES 5.2.3 Adjustment System 5.2.4 Transmitter Adjustment Procedure TEST TUNING STEP ITEM POINT CONTROL PROCEDURE Initial Turn the volume on APC RV1, Setting fully counterclockwise (CCW). Confirming Disconnect RF cable P101 from the voltage connector J201. Turn on the power. Turn on the PTT (ground J701-2). - Page 18 ALIGNMENT AND TROUBLESHOOTING PROCEDURES 5.2.5 Transmitter Troubleshooting LBI-38438A...
- Page 19 ALIGNMENT AND TROUBLESHOOTING PROCEDURES LBI-38438A...
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Page 20: Receiver
ALIGNMENT AND TROUBLESHOOTING PROCEDURES RECEIVER Alignment and Troubleshooting for Receiver Circuitry on Transmitter/Receiver Board CMN-233A/B. 5.3.1 Receiver Alignment 5.3.1.1 Equipment Required 1. RF Signal Generator (29 - 50 MHz) 2. DC Voltmeter 3. Frequency Counter (up to 100 MHz with 0.05 V sensitivity) 4. -
Page 21: Alignment Procedure
ALIGNMENT AND TROUBLESHOOTING PROCEDURES 5.3.2 Alignment Procedure TEST TUNING METER STEP POINT CONTROL READING PROCEDURE TP501 9.0 ± 0.2 Connect the DC Voltmeter to TP501. TP503 L513 Set the signal generator on the Procedure receive frequency with ±3 kHz deviation and 1 kHz modulation. Set the RF signal level to 1000 microvolts. -
Page 22: Receiver Test Procedures
ALIGNMENT AND TROUBLESHOOTING PROCEDURES 5. Check that the squelch opens at an input signal level corresponding to 8 dB SINAD (±1 dB). 6. Remove ground from J701-7 or re-enable Channel Guard. 5.3.4 Receiver Test Procedures These Test Procedures are designed to help you service a receiver that is operating, but not properly. - Page 23 ALIGNMENT AND TROUBLESHOOTING PROCEDURES 2. Place the RANGE switch on the Distortion Analyzer in the 200 to 2000 Hz distortion range position (1000 Hz filter in the circuit). Tune the filter for minimum reading or null on the lowest possible scale (100%, 30%, etc.). 3.
- Page 24 ALIGNMENT AND TROUBLESHOOTING PROCEDURES 5.3.5.4 Receiver Troubleshooting LBI-38438A...
- Page 25 ALIGNMENT AND TROUBLESHOOTING PROCEDURES LBI-38438A...
- Page 26 Com-Net Ericsson Critical Radio Systems, Inc. P.O. Box 2000 Lynchburg, Virginia 24501 Phone: 1-800-431-2345 or (Outside USA, 1-804-592-6100) www.com-netericsson.com Printed in U.S.A.