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GM950E/GM950i Mobile Radio Service Manual 6804111J39-B Issue: May, 2000...
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Cautions and Warnings CAUTION ELECTROSTATIC SENSITIVE DEVICES PRECAUTIONS SHOULD BE TAKEN TO MINIMIZE THE RISK OF DAMAGE BY ELEC- TROSTATIC DISCHARGE TO ELECTROSTATIC SENSITIVE DEVICES (ESDs). ANY DEVICES EMPLOYING METAL OXIDE SILICON (MOS) TECHNOLOGY ARE PARTICULARLY SUSCEPTIBLE. CIRCUIT DIAGRAMS MARKED WITH THE ABOVE SYMBOL INDICATE ELECTRONIC CIRCUITS (PECs) FOR WHICH ESD HANDLING PRECAUTIONS ARE NECESSARY.
Cautions and Warnings SAFETY WARNINGS THE ELECTRICAL POWER USED IN THIS EQUIPMENT IS AT A VOLTAGE HIGH ENOUGH TO ENDANGER LIFE. BEFORE CARRYING OUT MAINTENANCE OR REPAIR, PERSONS CONCERNED MUST ENSURE THAT THIS EQUIPMENT IS ISOLATED FROM THE ELECTRICAL SUPPLY AND TESTS ARE MADE TO ENSURE THAT ISOLATION IS COMPLETE.
Contents Service Manual Contents Chapter Introduction Gives a brief introduction into the manual and the service policy. Model Chart and Accessories Provides list of models and accessories available for the mobile radio. Maintenance Describes how to disassemble/assemble the radio for maintenance purposes and gives details on safety precautions.
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How to Use This Manual ................1 Warranty and Service Support ..............1 Waranty Period .................... 1 After Warranty Period .................. 1 Piece Parts ....................2 Technical Support..................2 GM950E/GM950i Technical SpeciÞcation ..........2 General ....................... 2 Transmitter....................3 Receiver...................... 3 Introduction...
In instances where the product is covered under a "return for replacement" or "return for repair" warranty, a check of the product should be performed prior to shipping the unit back to Motorola. To ensure the product has been correctly programmed or has not been subjected to damage outside the terms of the warranty.
Aftermarket Division (AAD). If a generic part is listed or only a part description is listed, the part is not normally available from Motorola. If a parts list is not included, this generally means that no user-serviceable parts are available for that kit or assembly. All orders for parts/information should include the complete Motorola identiÞcation number.
Table of Contents Chapter 2 Model Chart and Accessories Table of Contents Paragraph Page Overview..................... 1 Model Chart ....................1 Accessories....................2 Mechanical Hardware Kits: ................2 Microphones: ....................2 Speakers:..................... 2 Cables:......................2 Other:......................2 Model Chart and Accessories...
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Table of Contents 2-ii Model Chart and Accessories...
Overview Overview This chapter lists the models and accessories available for the GM950E/GM950i mobile radio. Model Chart GM950E/GM950i 136-174 MHz VHF 403-470 MHz UHF X = Indicates one of each required Item Description PMBN4039_ Packaging Kit GCN6103_ Control Head Model A2 Non-Display...
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Table of Contents Chapter 3 Maintenance Table of Contents Paragraph Page Overview..................... 1 Disassemble the Radio ................1 Remove the Control Head ................1 Remove the Top Cover................1 Remove the Transceiver Board ..............2 Disassemble the Control Head ..............2 Assemble Radio..................
Overview Overview This chapter explains, step by step, how to disassemble and assemble the radio, to transceiver board level. The chapter also contains a list of test equipment required to service the radio. The procedure for radio alignment and the test setup is also available in this chapter. Disassemble the Radio Remove the Control Head Recess...
Disassemble the Radio Insert a small ßat blade screw driver in the side recess of the radio chassis. Lift the top cover over the chassis. Remove the Transceiver Board Protruding Tabs Flex Clip Flex Recess Clip Recess Chassis Recess Printed Circuit Board Top Cover Chassis Transceiver Board...
Assemble Radio Assemble Radio Assemble the Control Head Protuding Tabs Recess Keypad Recess Speaker Control Head Housing Printed Circuit Board Figure 3-4 Control Head Assembly. Place the keypad onto the board assembly, making sure the keypad is ßush with the board. Make sure the speaker including the gasket is well positioned.
Exploded View Diagrams and Parts Recess Figure 3-5 Control Head Replacement. Exploded View Diagrams and Parts Cover Chassis 1502609Y01 incl. Gasket Chassis 3202619Y01 Shield 2602640Y01 Screw M3x10 03S10911A12 Controlhead with Shield or without LCD Main 2602639Y01 Accessory Conn. 16Pin 2804503J01 Power Conn.
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Exploded View Diagrams and Parts Housing 1502611Y02 Keypad 7502614Y02 Gasket 3505932V01 Printed Circuit Board Speaker 5005156Z02 8480573Z01 Figure 3-7 Control Head Model A2. Housing incl. LCD Gasket 1502612Y03 Connector Elastromeric 2802638Y04 top 2802638Y03 bottom Printed Circuit Board 8480479Z01 7202662Y01 Speaker Frame LCD 5005156Z02 0702643Y01...
Service Aids Service Aids The list in table 3-1 includes service aids recommended for working on the GM950E/GM950i radio. Table 3-1 Service Aids. PART No. DESCRIPTION APPLICATION GTF376 Test Box Cable Connects radio to GTF180 test box. GTF374 Combined Interface Connects radio to RLN4008 RIB.
Battery-operated test equipment is recommended when available. The ÒCharacteristicsÓ column is included so that equivalent equipment may be substituted; however, when no information is provided in this column, the speciÞc Motorola model listed is either a unique item or no substitution is recommended.
Radio Tuning Procedure Radio Tuning Procedure General The recommended hardware platform is a 386 or 486 DX 33 PC (personal computer) with 8 MBytes RAM, MS DOS 5.0, Windows 3.1, and RSS (Radio Service Software). These are required to align the radio.
Radio Tuning Procedure The Service windows introduce the concept of the ÒSoftpotÓ, an analog SOFTware controlled POTentiometer used for adjusting all transceiver alignment controls. A softpot can be selected by clicking with the mouse at the value or the slider or by hitting the TAB key until the value or the slider is highlighted.
Only if the transmitter components have been changed should the following procedure be performed. The advanced power setting technology employed in the GM950E/GM950i makes use of two reference power level settings along with parameters describing the circuit behaviour. To set the reference points requires tuning on two power level settings, a high power level setting, and a low power level setting.
Radio Tuning Procedure Reference Oscillator Adjustment of the reference oscillator is critical for proper radio operation. Improper adjustment will not only result in poor operation, but also a misaligned radio that will interfere with other users operating on adjacent channels. For this reason, the reference oscillator should be checked every time the radio is serviced.
Radio Tuning Procedure Table 3-5 Start Value for Front-End Pre-selector Tuning. RF-Band Start Value Maximum Minimum Table 3-6 Normal Test Deviation. Channel Spacing Deviation 12.5 kHz 1.5 kHz 20 kHz 2.4 kHz 25 kHz 3 kHz Rated Volume The rated volume softpot sets the volume at normal test modulation. Set test box (GTF180B) meter selection switch to the ÒAUDIO PAÓ...
The transmit deviation limit softpot sets the maximum deviation of the carrier. Unlike other radios, the deviation limit for GM950E/GM950i is set using low frequency (PL) rather than the usual 1kHz tone. The deviation value needs to be set at 7 frequencies across the frequency range. No audio signals need to be injected, as the radio generates a 82.5Hz tone while the deviation limit alignment...
Radio Tuning Procedure 7.10 Transmit Modulation Balance (Compensation) Compensation alignment balances the modulation sensitivity of the VCO and reference modulation (synthesizer low frequency port) lines. Compensation algorithm is critical to the operation of signalling schemes that have very low frequency components (e.g. PL) and could result in distorted waveforms if improperly adjusted.
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Table of Contents Chapter 4 Theory of Operation Table of Contents Paragraph Page Overview..................... 1 Controller....................2 General ......................2 Voltage Regulators ..................2 Electronic On/Off ..................3 Mechanical On/Off ..................3 Ignition ......................3 Hook ......................4 Microprocessor Clock Synthesizer .............. 4 Serial Peripheral Interface (SPI) ..............
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Table of Contents 12.0 Power AmpliÞer (PA) 5-25W ..............25 12.1 Power Controlled Stage ................25 12.2 PA Stages ....................26 12.3 Directional Coupler ................... 26 12.4 Antenna Switch ..................26 12.5 Harmonic Filter..................27 12.6 Power Control ................... 27 13.0 Frequency Synthesis ................
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Table of Contents 4-iv Theory of Operation...
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Overview Overview This section provides a detailed theory of operation for the radio and its components. The main radio is designed to accept one additional option board. This may provide functions such as secure voice/or a signalling decoder. The control head is mounted directly on the front of the radio. The control head contains a speaker, LED indicators, a microphone connector, buttons and dependant of radio type, a display.
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The digital section consists of a microprocessor, support memory, support logic, signal MUX ICs, the On/Off circuit, and general purpose Input/Output circuitry. The closed architecture controller uses the Motorola 68HC11E9 (U0101) for a GM950E radio and the 68HC11E20 for a GM950i radio. In this conÞguration RAM and ROM are contained within the microprocessor itself.
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Controller The voltage 9V3 SUPP is only used in the VHF radio to supply the drain current for the RF MOS FET in the PA. The voltage SW B+ is monitored by the mP through the voltage divider R0641/R0642. Diode VR0641 limits the divided voltage to 5.1V to protect the mP.
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Controller When the IGNITION input goes below 6 volts, Q0421 switches off and R0426, R0427 pull line IGNITION SENSE high. The software is alerted by line IGNITION SENSE to switch off the radio by setting B+ CONTROL to low. The next time the IGNITION input goes above 6 volts the above process will be repeated.
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GP3,5,6 are bidirectional. The software and the hardware conÞguration of the radio model deÞne the function of each port. Some ports are not connected on GM950E radio, refer to appendix B. GP1 can be used as external PTT input or others, set by the RSS.
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Controller C0622 allows the battery voltage to be disconnected for a couple of seconds without losing RAM parameters. Diode D0621 prevents radio circuitry from discharging this capacitor. U0101-22 is the high reference voltage for the A/D ports on the E9/20µP. Resistor R0105 and capacitor C0105 Þlter the +5V reference.
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General CONTROLLER BOARD AUDIO AND SIGNALLING CIRCUITS General Audio Filter IC (AFIC) The AFIC (U0103) used in the controller performs RX/TX audio shaping, i.e. Þltering, ampliÞcation, attenuation. The AFIC is programmable through the SPI BUS (U0103-30/31/33), normally receiving 6 bytes. This programming sets up various paths within the AFIC to route audio signals through the appropriate Þltering, gain and attenuator blocks.
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Transmit Audio Circuits The FLAT TX AUDIO signal from accessory connector U0400-5 is buffered by op-amp U0106-1 and fed to the AFIC U0103-13 through gate U0107-1. Gate U0107-1 is controlled by the µP port PC7 (U0101-42) and selects between FLAT TX AUDIO or signalling signal created by the µP. J0101 J0103-1 J0103-3...
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Transmit Audio Circuits Option Board Audio (GM950i only) The audio coming from the microphone (J0101-16) or the external microphone (J0400-2) is routed through op-amp buffer U0106-2 (128ch only) to the option board connector J0103-3. After option board processing the signal emerges at J0103-1. The source resistor of the option board output and C0145, the ampliÞer inside the AFIC (U0103-9,10) and gain setting resistor R0147 pre-emphasise the signal.
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Transmit Signalling Circuits Transmit Signalling Circuits Refer to Figure 4-2 for reference for the following sections. From a hardware point of view, there are three types of signalling: Sub-audible data (PL / DPL / Connect Tone) that gets summed with transmit voice or signal- ling, DTMF data for telephone communication in trunked and conventional systems, and Audible signalling including Select 5, MPT-1327, MDC, Single Tones.
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Transmit Signalling Circuits High Speed Data and DTMF The High Speed Data and DTMF waveforms are created by the µP U0101 using summer U0105-3. Op-amp U0105-3 and resistors R0121-R0124 add up the three signals coming from the µP pins 58, 59 and 62.
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Receive Audio Circuits Receive Audio Circuits Refer to Figure 4-3 for reference for the following sections. ACCESSORY CONNECTOR FLAT RX AUDIO J0400 AUDIO SPKR + EXTERNAL SPKR - U0401 SPEAKER SPKR- SPKR+ CONTROL HEAD CONNECTOR ATTEN. INTERNAL SPEAKER J0101 HANDSET AUDIO RX AUD OUT UNAT...
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Receive Audio Circuits Audio Processing and Digital Volume Control The receiver audio signal enters the controller section from the IF IC (U5201-28) on DET AUDIO. The signal is AC coupled by C0181 and enters the AFIC via the RX IN pin U0103-7. Inside the AFIC the signal entering RX IN (U0103-7) goes through the audio path while the signal entering PL DPL IN (U0103-8) via C0182 goes through the PL/DPL path.
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Receive Audio Circuits The SPK+ and SPK- outputs of the audio PA have a DC bias which varies proportionately with FLT A+ (U0401-7). FLT A+ of 11V yields DC offset of 5V, and FLT A+ of 17V yields a DC offset of 8.5V. If either of these lines is shorted to ground, it is possible that the audio PA will be damaged.
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Receive Signalling Circuits Receive Signalling Circuits Refer to Figure 4-4 for reference for the following sections. HIGH SPEED DATA CENTER SLICER U0105-2 UNATTEN RX OUT PL CLOCK STROBE MICRO AFIC CONTROLLER U0103 U0101 GEPD_5430 PL DPL DET AUDIO LIMITER FILTER DECODER DISCRIMINATOR AUDIO FROM RF SECTION...
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Receive Signalling Circuits Alert Tone Circuits When the software determines that it needs to give the operator an audible feedback (for a good key press, or for a bad key press), or radio status , it sends an alert tone to the speaker. It does so by sending SPI BUS data to U0103 which sets up the audio path to the speaker for alert tones.
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Receiver Front-End UHF SPECIFIC CIRCUIT DESCRIPTION Receiver Front-End The receiver is able to cover the UHF range from 403 to 470 MHz. It consists of four major blocks: front-end, mixer, Þrst IF section and IF IC. Antenna signal pre-selection is performed by two varactor tuned bandpass Þlters.
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Power AmpliÞer (PA) 5-25W. IF IC (U5201) The Þrst IF signal from the crystal Þlters feeds the IF IC (U5201) at pin 6. Within the IF IC the 45.1MHz Þrst IF signal mixes with the second local oscillator (LO) at 44.645MHz to the second IF at 455 kHz.
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Power AmpliÞer (PA) 5-25W. By controlling the output power of Q5510 and in turn the input power of the following stages the ALC loop is able to regulate the output power of the transmitter. PA Stages The bipolar transistor Q5520 is driven by Q5510. To reduce the collector - emitter voltage and in turn the power dissipation of Q5510 its collector current is drawn from the antenna switch circuit.
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Power AmpliÞer (PA) 5-25W. A high impedance resonant circuit formed by D5551 in off state and L5554, C5559 prevents an inßuence of the receive signal by the PA stages. The high impedance of D5631 in off state doesn«t inßuence the receiver signal. Harmonic Filter The transmitter signal from the antenna switch is channelled through the harmonic Þlter to the antenna connector J5501.The harmonic Þlter is formed by inductors L5552, L5553, and capacitors...
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Frequency Synthesis Loop frequency response is controlled by opamp feedback components R0712 and C0711. Opamp U0701-3 compares the power control voltage PWR CNTL divided by resistors R0717 to R0719 with the voltage limit setting VLTG LIMIT SET from the D/A converter (U0731-13) and keeps the control voltage constant via Q0711 if the control voltage, reduced by the resistive divider (R0717 to R0719), approaches the voltage of VLTG LIMIT SET (U0731-13).
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Frequency Synthesis In order to generate a high voltage to supply the phase detector (charge pump) output stage at pin VCP (U5701-32), a voltage of 13 VDC is being generated by the positive voltage multiplier circuitry (D5701-1-3, C5716, C5717). This voltage multiplier is basically a diode capacitor network driven by two (1.05MHz) 180 degrees out of phase signals (U5701-9 and -10).
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Frequency Synthesis The output signal of the phase detector is a pulsed DC signal which is routed to the charge pump. The charge pump outputs a current at pin 29 (I OUT of U5701). The loop Þlter (which consists of R5715-R5717, C5723-C5725, C5727) transforms this current into a voltage that is applied to the varactor diodes D5741, D5742 and alters the output frequency of the VCO.
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Receiver Front-End VHF SPECIFIC CIRCUIT DESCRIPTION 11.0 Receiver Front-End The receiver is able to cover the VHF range from 136 to 174 MHz. It consists of four major blocks: front-end, mixer, Þrst IF section and IF IC. Antenna signal pre-selection is performed by two varactor tuned bandpass Þlters.
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Power AmpliÞer (PA) 5-25W 11.3 IF IC (U5201) The Þrst IF signal from the crystal Þlters feeds the IF IC (U5201) at pin 6. Within the IF IC the 45.1MHz Þrst IF signal mixes with the second local oscillator (LO) at 44.645MHz to the second IF at 455 kHz.
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Power AmpliÞer (PA) 5-25W In receive mode the PA control line (PWR CNTL) is at ground level and switches off the collector current of Q3641 which in turn switches off the current source transistor Q3642 and the RF transistor Q3511. 12.2 PA Stages The following stage uses an enhancement mode N-Channel MOS FET device (Q3521) and requires...
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Power AmpliÞer (PA) 5-25W 12.5 Harmonic Filter The transmitter signal from the antenna switch is channelled through the harmonic Þlter to the antenna connector J3501.The harmonic Þlter is formed by inductors L3551, L3552, and capacitors C3551 - C3554 This network forms a low-pass Þlter to attenuate harmonic energy of the transmitter to speciÞcations level.
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Frequency Synthesis Rise and fall time of the output power during transmitter keying and dekeying is controlled by the comparator formed by opamp U0701-3. During normal transmitter operation the voltage at U701-3 pin 13 is higher than the voltage at pin 12 causing the output at pin 14 being low and switching off transistor Q0711.
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Frequency Synthesis Output LOCK (U3701-2) provides information about the lock status of the synthesizer loop. A high level at this output indicates a stable loop. IC U3701 divides the 16.8 MHz reference frequency down to 2.1 MHz and provides it at pin 11. This signal is used as clock signal by the controller. The serial interface (SRL) is connected to the microprocessor via the data line SPI DATA (U3701-5), clock line SPI CLK (U3701-6), and chip enable line FRACN CE (U3701-7).
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Frequency Synthesis The output signal of the phase detector is a pulsed DC signal which is routed to the charge pump. The charge pump outputs a current at pin 29 (I OUT of U3701). The loop Þlter (which consists of R3715 - R3717, C3723 - C3725, C3727) transforms this current into a voltage that is applied to the varactor diodes D3732, D3733 (TX), D3751, D3752 (RX) and alters the output frequency of the TX VCO (Q3741) and RX VCO (Q3751).
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Parts List ............. 9 Main Board - UHF GM950E, Controller Schematic Diagram 1 of 2....13 Main Board - UHF GM950E, Controller Schematic Diagram 2 of 2.
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Parts List............57 Main Board - VHF GM950E, Controller Schematic Diagram 1 of 2 ....61 Main Board - VHF GM950E, Controller Schematic Diagram 2 of 2 .
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UHF Main Board - Synthesizer 5-36 Schematic Diagrams and Parts Lists...
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UHF Voltage Controlled Oscillator Schematic Diagram UHF Voltage Controlled Oscillator Schematic Diagram Schematic Diagrams and Parts Lists 5-37...
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UHF Main Board - Voltage Controlled Oscillator UHF Main Board - Voltage Controlled Oscillator Circuit Motorola Circuit Motorola Description Description Part No. Part No. C5731 2113741F25 1nF 50V C5783 2113740F21 5.6pF 5% 50V C5732 2113740F37 27pF 5% 50V C5784 2113740F35...
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Control Head K D0843 D0868 D0866 D0867 D0842 D0841 J0803 D0844 D0848 D0847 D0846 D0845 D0864 D0863 D0862 D0861 D0865 Control Head ÔKÕ Component Side R0813 Q0843 C0826 R0812 D0825 R0845 R0811 R0814 Q0841 R0841 R0846 VR0809 R0843 VR0801 Q0862 Q0842 J0801 U0841...
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Control Head K Schematic Diagram Control Head K Schematic Diagram Schematic Diagrams and Parts Lists 5-99...
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Main Board - Control Head K Main Board - Control Head K Circuit Motorola Circuit Motorola Description Description Part No. Part No. C0801 2113741F17 470pF 50V X7R R0845 0662057A89 RES CHP 47k 1/16W 5% C0802 2113741F17 470pF 50V X7R R0846...
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5-102 Schematic Diagrams and Parts Lists...
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Control Head P H0931 D0943 D0956 D0957 D0964 D0953 D0961 D0965 D0969 D0968 D0941 D0942 D0966 D0954 D0958 D0962 D0970 J0903 D0952 D0944 D0960 R0902 D0951 D0955 D0959 D0963 D0967 Control Head ÔPÕ Component Side D0925 R0945 R0912 R0946 Q0943 R0911 R0913 R0922...
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Control Head P Schematic Diagram Control Head P Schematic Diagram Schematic Diagrams and Parts Lists 5-105...
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Main Board - Control Head P Main Board - Control Head P Circuit Motorola Circuit Motorola Description Description Part No. Part No. C0901 2113741F17 470pF 50V R0925 0662057A65 4k7 1/16W 5% C0902 2113741F17 470pF 50V R0926 0662057A65 4k7 1/16W 5%...
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Main Board - Control Head P 5-108 Schematic Diagrams and Parts Lists...
Table of Contents Chapter 6 216-246MHz Specific Information Table of Contents Chapter Model Chart and Technical Specifications Radio Tuning Procedure Theory of Operation PCB/Schematic Diagrams and Parts Lists 216-246MHz Specific Information...
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Table of Contents 6-ii 216-246MHz Specific Information...
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Table of Contents Chapter 6.1 Model Chart and Technical Specifications Table of Contents Paragraph Page Overview ..................... 1 Model Chart ....................1 Technical Specifications ................2 General ......................2 Transmitter....................2 Receiver....................... 3 Model Chart and Technical Specifications 6.1-i...
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Table of Contents 6.1-ii Model Chart and Technical Specifications...
Technical Specification Technical Specification General SPECIFICATION ITEM TYPICAL VALUE Frequency Range 216-246 MHz Channel Spacing 12.5 or 20/25 kHz Frequency Stability ±3ppm Power Supply 10.8 to 15.6V dc, negative earth Dimensions 44x168x160 mm (HxWxD) Weight 1030g Operational Temperature - 25°C to + 55°C Storage Temperature - 40°C to + 85°C 50 Ω...
216-246MHz Tuning Procedure 216-246MHz Tuning Procedure General The recommended hardware platform is a 386 or 486 DX 33 PC (personal computer) with 8 MBytes RAM, MS-DOS™ 5.0, Windows™3.1, and RSS (Radio Service Software). These are required to align the radio. Refer to your RSS Installation Manual for installation and setup procedures for the required software;...
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216-246MHz Tuning Procedure CAUTION: DO NOT switch radios in the middle of any Service procedure. Always use the Program or Cancel key to close the tuning window before disconnecting the radio. Improper exits from the Service window may leave the radio in an improperly configured state and result in seriously degraded radio or system performance.
216-246MHz Tuning Procedure PA Bias Voltage Adjustment of the PA Bias is critical for proper radio operation. Improper adjustment will result in poor operation and may damage the PA FET device. For this reason, the PA bias must be set before the transmitter is keyed the first time.
216-246MHz Tuning Procedure Transmitter Power The radio has two power level settings, a high power level setting, and a low power level setting. IMPORTANT: To set the transmitter power for customer applications use the Per Radio window under the Edit menu and set the “Power 1” and “Power 2” powers to the desired values.
216-246MHz Tuning Procedure Table 6.2-2 Reference Oscillator Alignment. RF-Band Target All bands ±150 Hz Front-End Filter Alignment of the front-end pre-selector is normally not required on these radios. Only if the radio has poor receiver sensitivity or the pre-selector parts have been replaced the following procedure should be performed.
216-246MHz Tuning Procedure Rated Volume The rated volume softpot sets the maximum volume at normal test modulation. Set test box (GTF180) meter selection switch to the “AUDIO PA” position and the speaker load switch to the “MAXAR” position. Connect an AC voltmeter to the test box meter port. From the Service menu, select Rx Alignments.
216-246MHz Tuning Procedure Transmit Deviation Limit The transmit deviation limit softpot sets the maximum deviation of the carrier. The deviation limit needs to be set at 7 frequencies across the frequency range. Unlike other radios, the deviation limit for 216-246MHz is set using low frequency (PL) rather than the usual 1 kHz tone. No audio signal must be injected, the radio generates a 82.5 Hz tone while the deviation limit alignment window is open.
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216-246MHz Tuning Procedure Click the Toggle PTT button to key the radio. The status bar will indicate that the radio is transmitting. Measure the transmitter deviation. Adjust the transmitter deviation to the value shown in table 6.2-6. Click the Toggle PTT button to dekey the radio. 10.
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Table of Contents Chapter 6.3 Theory of Operation Table of Contents Paragraph Page Overview..................... 1 Controller....................2 General ......................2 Voltage Regulators ..................2 Electronic On/Off ..................3 Mechanical On/Off ..................3 Ignition ......................3 Hook ......................4 Microprocessor Clock Synthesizer .............. 4 Serial Peripheral Interface (SPI) ..............
Overview Overview This section provides a detailed theory of operation for the radio and its components. The main radio is designed to accept one additional option board. This may provide functions such as secure voice/or a signalling decoder. The control head is mounted directly on the front of the radio. The control head contains a speaker, LED indicators, a microphone connector, buttons and dependant of radio type, a display.
The digital section consists of a microprocessor, support memory, support logic, signal MUX ICs, the On/Off circuit, and general purpose Input/Output circuitry. The closed architecture controller uses the Motorola 68HC11E9 (U0101) for a GM950E radio and the 68HC11E20 for a GM950i radio. In this configuration RAM and ROM are contained within the microprocessor itself.
Controller The voltage SW B+ is monitored by the µP through the voltage divider R0641/R0642. Diode VR0641 limits the divided voltage to 5.1V to protect the µP. Diode D5601 (UHF) / D3601 (VHF) located on the PA section acts as protection against transients and wrong polarity of the supply voltage.
Controller When the IGNITION input goes below 6 volts, Q0421 switches off and R0426, R0427 pull line IGNITION SENSE high. The software is alerted by line IGNITION SENSE to switch off the radio by setting B+ CONTROL to low. The next time the IGNITION input goes above 6 volts the above process will be repeated.
Controller The timing and operation of this interface is specific to the option connected, but generally follows the pattern: 1) an option board device generates the interrupt, 2) main board asserts a chip select for that option board device, 3) the main board µP generates the CLK, and 4) when data transfer is complete the main board terminates the chip select and CLK activity.
Controller C0622 allows the battery voltage to be disconnected for a couple of seconds without losing RAM parameters. Diode D0621 prevents radio circuitry from discharging this capacitor. U0101-22 is the high reference voltage for the A/D ports on the E9/20µP. Resistor R0105 and capacitor C0105 filter the +5V reference.
The MIC signal is routed to the AFIC´s TX IN input (U0103-10) through R0146 and R0145 (GM950E radio) or through Op-amp buffer U0106-2 and option board connector J0103-3,1 (GM950i radio).
PTT. The MIC signal is routed to the AFIC (U0103) through R0146 and R0145 (GM950E radio) or through Op-amp buffer U0106-2 and option board connector J0103-3,1 (GM950i radio). R0145, C0145, the amplifier inside the AFIC (pins 9,10) and gain setting resistor R0147 pre-emphasise the MIC audio...
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Transmit Audio Circuits Option Board Audio (GM950i only) The audio coming from the microphone (J0101-16) or the external microphone (J0400-2) is routed through Op-amp buffer U0106-2 (GM950i only) to the option board connector J0103-3. After option board processing the signal emerges at J0103-1. The source resistor of the option board output and C0145, the amplifier inside the AFIC (U0103-9,10) and gain setting resistor R0147 pre-emphasise the signal.
Transmit Signalling Circuits Transmit Signalling Circuits Refer to Figure 6.3-2 for reference for the following sections. From a hardware point of view, there are three types of signalling: Sub-audible data (PL / DPL / Connect Tone) that gets summed with transmit voice or signal- ling, DTMF data for telephone communication in trunked and conventional systems, and Audible signalling including Select 5, MPT-1327, MDC, Single Tones.
Transmit Signalling Circuits High Speed Data and DTMF The High Speed Data and DTMF waveforms are created by the µP U0101 using summer U0105-3. Op-amp U0105-3 and resistors R0121-R0124 add up the three signals coming from the µP pins 58, 59 and 62.
Receive Audio Circuits Audio Processing and Digital Volume Control The receiver audio signal enters the controller section from the IF IC (U5201-28) on DET AUDIO. The signal is AC coupled by C0181 and enters the AFIC via the RX IN pin U0103-7. Inside the AFIC the signal entering RX IN (U0103-7) goes through the audio path while the signal entering PL DPL IN (U0103-8) via C0182 goes through the PL/DPL path.
Receive Audio Circuits The SPK+ and SPK- outputs of the audio PA have a DC bias which varies proportionately with FLT A+ (U0401-7). FLT A+ of 11V yields DC offset of 5V, and FLT A+ of 17V yields a DC offset of 8.5V. If either of these lines is shorted to ground, it is possible that the audio PA will be damaged.
Receive Signalling Circuits Receive Signalling Circuits Refer to Figure 6.3-4 for reference for the following sections. HIGH SPEED DATA CENTRE SLICER U0105-2 UNATTEN RX OUT PL CLOCK STROBE MICRO AFIC CONTROLLER U0103 U0101 PL DPL DET AUDIO LIMITER FILTER DECODER DISCRIMINATOR AUDIO GEPD_5430 FROM RF SECTION...
Receive Signalling Circuits Alert Tone Circuits When the software determines that it needs to give the operator an audible feedback (for a good key press, or for a bad key press), or radio status , it sends an alert tone to the speaker. It does so by sending SPI BUS data to U0103 which sets up the audio path to the speaker for alert tones.
Receiver Front-End 216-246MHz SPECIFIC CIRCUIT DESCRIPTION Receiver Front-End The receiver is able to cover the range from 216 to 246 MHz. It consists of four major blocks: front- end, mixer, first IF section and IF IC. Antenna signal pre-selection is performed by two varactor tuned bandpass filters.
Transmitter Power Amplifier (PA) 5-25W The IF amplifier Q5201 is actively biased by a collector base feedback (R5201, R5202) to a current drain of approximately 5 mA drawn from the voltage 5V STAB. The output impedance is matched to the second two pole crystal filter Y5202. A dual hot carrier diode (D5201) limits the filter output voltage swing to reduce overdrive effects at RF input levels above -27 dBm.
Transmitter Power Amplifier (PA) 5-25W The collector current of Q8510 causes a voltage drop across the resistors R8623 and R8624. Transistor Q8612 adjusts the voltage drop across R8621 through PA control line (PWR CNTL). The current source Q8621 adjusts the collector current of Q8510 by modifying its base voltage until the voltage drop across R8623 and R8624 plus VBE (0.6V) equals the voltage drop across R8621 plus VBE (0.6V) of Q8611.
Transmitter Power Amplifier (PA) 5-25W In transmit mode, this K9V1 voltage is high and biases Q8520 and, along with the RF signal from Q8510, allows a collector current to be drawn. The collector current of Q8520 drawn from A+ flows via L8542, L8541, directional coupler, D8551, L8551, D8631, L8631, R8616, R8617 and L8611 and switches the PIN diodes D8551 and D8631 to the low impedance state.
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Transmitter Power Amplifier (PA) 5-25W Op-amp U0701-2 and resistors R0701 to R0703 and R0731 subtract the negative PWR DETECT voltage from the PA PWR SET D/A output U0731 pin 2. The result is connected to Op-amp inverting input U0701-4 pin 9 which is compared with a 4.6 volt reference VAG present at noninverting input U0701-4 pin 10 and controls the output power of the PA via pin 8 and control line PWR CNTL.
Frequency Synthesis 10.0 Frequency Synthesis The complete synthesizer subsystem consists of the Reference Oscillator (Y3702 or Y3701), the Fractional-N synthesizer (U3701), the Voltage Controlled Oscillator (Q3741, Q3751), the RX and TX buffer stages (Q3760, Q3770, Q3780) and the feedback amplifier (Q3790). 10.1 Reference Oscillator The Reference Oscillator (Y3702) contains a temperature compensated crystal oscillator with a...
Frequency Synthesis Diode D3754 controls the amplitude of the oscillator. The frequency of the transmit oscillator is mainly determined by L3734, C3736 - C3740 and varactor diodes D3732 / D3733. Diode D3739 controls the amplitude of the oscillator. With a steering voltage from 3V to 10V at the varactor diodes the RX frequency range from 181.1 MHz to 219.1 MHz and the TX frequency range from 136 MHz to 174 MHz are covered.
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Frequency Synthesis The balance attenuator is used to adjust the VCO’s deviation sensitivity to high frequency modulating signals. The output of the balance attenuator is present at the MODOUT port (U3701- 28) and connected to the VCO modulation diode D3731. 6.3-24 Theory of Operation...
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Table of Contents Chapter 6.4 PCB/Schematic Diagrams and Parts Lists Table of Contents Description Page 216-246MHz Diagrams and Parts Lists PCB Layout Component Side ..........1 PCB Layout Solder Side .
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Table of Contents 6.4-ii PCB/Schematic Diagrams and Parts Lists...
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Table of Contents Appendix A PL/DPL Codes Table of Contents Paragraph Page PL Codes and Digital PL (DPL) Codes ......1 Self-Quieting Frequencies .
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Table of Contents A-ii PL (CTCSS) Codes...
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PL Codes and Digital PL (DPL) Codes PL Codes and Digital PL (DPL) Codes The following PL Codes have been tested and are acceptable for programming into any transmit or receive frequency. GROUP A GROUP B GROUP C Code Freq Code Freq Code...
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Table of Contents Appendix B External Device Connectors Table of Contents Paragraph Page Accessory Connector Details ........1 Microphone Connector .
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Table of Contents B-ii External Device Connectors...
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Accessory Connector Details Accessory Connector Details The 16-pin accessory connector pin functions are as follows: Name Type 4-Channel 128-Channel SPKR- Analogue output Ext. Mic Audio Analogue input Digital input Digital output Flat TX Audio Analogue input BUS+ Digital i/o Ground Digital i/o Digital ip.
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Accessory Connector Details Pin 6. - BUS+ This connects to the radioÕs SCI serial bus which is used for programming and tuning the radio. The line is also available at the microphone connector Pin 7. Pin 7. - Ground Used as ground for both analogue and digital signals. Pin 8.
Microphone Connector Microphone Connector The radio is Þtted with an 8-pin ÔTelcoÕ connector which is connected as follows: Name Type Connected To Mic. Hook Digital input Port A7 Ground Mic. Audio Analogue input AFIC TX IN Mic. PTT Digital i/o Port C4 BUS+ Digital i/o...
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Table of Contents Appendix C Radio Conversion Table of Contents Paragraph Page How to alter the radio for Base Station Operation ....1 Radio Conversion...
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Table of Contents C-ii Radio Conversion...
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How to alter the radio for Base Station Operation How to alter the radio for Base Station Operation UHF Radio Conversion If the UHF radio is conÞgured for a base station application, R5319 is not placed and TP5301 and TP5302 are shorted. VHF Radio Conversion If the VHF radio is conÞgured for a base station application, R3318 is not placed and TP3301 and TP3302 are shorted.
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How to alter the radio for Base Station Operation Radio Conversion...