Page of 248
Download Table of ContentsContents Print This PagePrint Bookmark

Motorola ASTRO Digital Spectra Service Manual

Digital spectra and digital spectra plus uhf/vhf/800 mhz mobile radios.
Hide thumbs

Advertisement

®
®
ASTRO
Digital Spectra
and Digital Spectra Plus
UHF/VHF/800 MHz Mobile Radios
Detailed Service Manual

Advertisement

   Related Manuals for Motorola ASTRO Digital Spectra

   Summary of Contents for Motorola ASTRO Digital Spectra

  • Page 1

    ® ® ASTRO Digital Spectra and Digital Spectra Plus UHF/VHF/800 MHz Mobile Radios Detailed Service Manual...

  • Page 2: Diagram

    ASTRO Digital Spectra Plus mobile radios (models W3, W4, W5, W7, and W9) to the component level. For the most part, the information in this manual pertains to both ASTRO Digital Spectra and ASTRO Digital Spectra Plus radios. Exceptions are clearly noted where they occur.

  • Page 3

    Mobile Radio Model Numbering Scheme ....................xix ASTRO Digital Spectra Motorcycle 15 Watt (Ranges 1 and 2) Model Chart..........xx ASTRO Digital Spectra Motorcycle 15 Watt (Ranges 3 and 3.5) Model Chart......... xxi ASTRO Digital Spectra VHF 10–25 Watt Model Chart................xxii ASTRO Digital Spectra VHF 10–25 and 50–110 Watt Model Chart............

  • Page 4: Table Of Contents

    Table of Contents Chapter 2 General Overview..............2-1 Introduction ............................ 2-1 Analog Mode of Operation ......................2-2 ASTRO Mode of Operation......................2-2 Control Head Assembly ......................... 2-2 2.4.1 Display (W3 Model)......................2-2 2.4.2 Display (W4, W5, and W7 Models) ................... 2-2 2.4.3 Display (W9 Model)......................

  • Page 5: Table Of Contents

    Table of Contents 3.2.4 Regulators ........................3-10 3.2.5 Reset Circuits ......................... 3-10 3.2.6 Serial Communications on the External Bus ..............3-11 3.2.7 Synchronous Serial Bus (MOSI) ..................3-12 3.2.8 Received Audio....................... 3-12 3.2.9 Microphone Audio ......................3-12 3.2.10 Transmit Deviation ......................3-13 3.2.11 RS-232 Line Driver ......................

  • Page 6

    Table of Contents 3.5.2.9 Doubler ........................3-50 3.5.2.10 Synthesizer Feedback ................... 3-50 3.5.2.11 Second Buffer ......................3-50 3.5.2.12 Receive/Transmit Switch ..................3-50 3.5.3 800 MHz Band ........................ 3-50 3.5.3.1 General ........................3-50 3.5.3.2 Super Filter 8.6 V ....................3-50 3.5.3.3 VCO ........................

  • Page 7: Table Of Contents

    Table of Contents Chapter 4 Troubleshooting Procedures ..........4-1 ASTRO Spectra Procedures......................4-1 4.1.1 Handling Precautions......................4-1 4.1.2 Voltage Measurement and Signal Tracing................ 4-2 4.1.3 Power-Up Self-Check Errors .................... 4-2 4.1.3.1 Power-Up Sequence....................4-3 4.1.4 RF Board Troubleshooting....................4-5 4.1.4.1 Display Flashes “FAIL 001”...

  • Page 8

    viii Table of Contents 4.5.1.3.1 General Troubleshooting and Repair Notes ........... 4-38 4.5.1.3.2 PA Functional Testing..................4-39 4.5.1.3.3 Localizing Problems..................4-42 4.5.1.3.4 Isolating Failures..................... 4-43 4.5.1.3.5 Power Control and Protection Circuitry............4-45 4.5.2 UHF Band ........................4-47 4.5.2.1 High-Power Amplifier ..................... 4-47 4.5.2.1.1 General Troubleshooting and Repair Notes ...........

  • Page 9: Table Of Contents

    Table of Contents ASTRO Spectra Plus VOCON DC Supply Failure ..............5-20 ASTRO Spectra Plus VOCON TX Modulation Failure Sheet 1 of 4........5-21 ASTRO Spectra Plus VOCON TX Modulation Failure Sheet 2 of 4 ........5-22 ASTRO Spectra Plus VOCON TX Modulation Failure Sheet 3 of 4........5-23 ASTRO Spectra Plus VOCON TX Modulation Failure Sheet 4 of 4 ........

  • Page 10

    Table of Contents HRN4009E and HRN6014D VHF RF Board; HRN4010D and HRN6020C UHF RF Board; and HRN6019C 800 MHz RF Component Location Diagram ............7-14 Command Board Section......................7-17 HLN5558E/F/G, HLN6529C/D/E/F/G, HLN6560C/D/E/F/G/H and HLN6562C/D/E/F/G/H Command Board Schematic Diagram ................... 7-17 HLN5558E/F/G, HLN6529C/D/E, HLN6560C/D/E/F/G/H, and HLN6562C/D/E/F/G/H Command Board Component Location Diagrams ..................

  • Page 11

    Table of Contents HLF6080B 800 MHz VCO Component Location Diagram ............ 7-80 RX Front-End Section........................7-82 HRD6001E/6002E/6011E/6012E VHF Receiver Front-End Schematic ........ 7-82 HRD6001E/6002E/6011E/6012E VHF Component Location Diagram ......... 7-83 HRD6001G/6002G/6011G/6012G VHF Receiver Front-End Schematic ......7-87 HRD6001G/6002G/6011G/6012G VHF Receiver Front-End Component Location Diagram 7-88 HRE6001B/6002C/6003B/6004B/6011B/6012B/6014B UHF Receiver Front-End Preamp and Standard Schematics ......................

  • Page 12

    Table of Contents Appendix B Replacement Parts Ordering..........B-1 Basic Ordering Information ......................B-1 Transceiver Board and VOCON Board Ordering Information............B-1 Motorola Online..........................B-1 Mail Orders ............................B-1 Telephone Orders ..........................B-2 Fax Orders .............................B-2 Parts Identification .........................B-2 Product Customer Service ......................B-2 Glossary ..................Glossary-1...

  • Page 13: Table Of Contents

    List of Figures xiii List of Figures Figure 2-1. DC Voltage Routing Block Diagram ..................2-9 Figure 2-2. ASTRO Spectra B+ Routing for Vocoder/Controller (VOCON) Board ........ 2-10 Figure 3-1. Prescaler IC Block Diagram....................3-2 Figure 3-2. Synthesizer IC Block Diagram ....................3-2 Figure 3-3.

  • Page 14: Vco Section

    ASTRO Digital Spectra and Digital Spectra Plus Model W3 User’s Guide ........68P81090C61 ASTRO Digital Spectra and Digital Spectra Plus Models W4, W5, W7, and W9 User’s Guide ... 68P81090C62 ASTRO Digital Spectra Hand-Held Control Head User’s Guide (Model W3)....... 68P81073C25 ASTRO Digital Spectra (Model W4, W5, W7, and W9) User’s Guide ..........

  • Page 15: Limited Warranty

    Product Accessories One (1) Year Motorola, at its option, will at no charge either repair the Product (with new or reconditioned parts), replace it (with a new or reconditioned Product), or refund the purchase price of the Product during the warranty period provided it is returned in accordance with the terms of this warranty. Replaced parts or boards are warranted for the balance of the original applicable warranty period.

  • Page 16

    Warranty service will be provided by Motorola through one of its authorized warranty service locations. If you first contact the company which sold you the Product, it can facilitate your obtaining warranty service. You can also call Motorola at 1-888-567-7347 US/Canada.

  • Page 17

    A. that MOTOROLA will be notified promptly in writing by such purchaser of any notice of such claim; B. that MOTOROLA will have sole control of the defense of such suit and all negotiations for its settlement or compromise; and C.

  • Page 18

    xviii Commercial Warranty This Page Intentionally Left Blank June 28, 2002 68P81076C25-C...

  • Page 19

    Model Numbering, Charts, and Specifications Model Numbering, Charts, and Specifications Mobile Radio Model Numbering Scheme Typical Model Number: Position: 12 13 Position 1 - Type of Unit Positions 13 - 16 D = Dash-Mounted Mobile Radio SP Model Suffix M = Motorcycle Mobile Radio T = Trunk-Mounted Mobile Radio Position 12 - Unique Model Variations...

  • Page 20

    Model Numbering, Charts, and Specifications ASTRO Digital Spectra Motorcycle 15 Watt (Ranges 1 and 2) Model Chart Model Number Description M04JGF9PW4AN Model W4 (136-162 MHz), Range 1, 15 Watt, 128 Channels M04JGF9PW5AN Model W5 (136-162 MHz), Range 1, 15 Watt, 128 Channels...

  • Page 21

    Model Numbering, Charts, and Specifications ASTRO Digital Spectra Motorcycle 15 Watt (Ranges 3 and 3.5) Model Chart Model Number Description M04RGF9PW4ANSP02 Model W4 (450-482 MHz), Range 3, 15 Watt, 128 Channels M04RGF9PW5ANSP02 Model W5 (450-482 MHz), Range 3, 15 Watt, 128 Channels M04RGF9PW4ANSP01 Model W4 (453-488 MHz), Range 3.5, 15 Watt, 128 Channels...

  • Page 22

    Model Numbering, Charts, and Specifications ASTRO Digital Spectra VHF 10–25 Watt Model Chart Model Number Description D04JHH9PW3AN Model W3 (136-145.9 MHz), 10-25 Watt, 255 Channels D04JHF9PW4AN Model W4 (136-162 MHz), 10-25 Watt, 128 Channels D04JHF9PW5AN Model W5 (136-162 MHz); 10-25 Watt, 128 Channels...

  • Page 23

    Model Numbering, Charts, and Specifications xxiii ASTRO Digital Spectra VHF 10–25 and 50–110 Watt Model Chart Model Number Description D04JKH9PW3AN Model W3 (136-145.9 MHz), 25-50 Watt, 128 Channels D04JKF9PW4AN Model W4 (136-162 MHz), 25-50 Watt, 128 Channels D04JKF9PW5AN Model W5 (136-162 MHz); 25-50 Watt, 128 Channels...

  • Page 24

    Model Numbering, Charts, and Specifications ASTRO Digital Spectra VHF 10–25 and 50–110 Watt Model Chart (cont.) Model Number Description D04JKH9PW3AN Model W3 (136-145.9 MHz), 25-50 Watt, 128 Channels D04JKF9PW4AN Model W4 (136-162 MHz), 25-50 Watt, 128 Channels D04JKF9PW5AN Model W5 (136-162 MHz); 25-50 Watt, 128 Channels...

  • Page 25

    Model Numbering, Charts, and Specifications ASTRO Digital Spectra UHF 10–25 Watt Model Chart Model Number Description D04RHH9PW3AN Model W3 (438-470 MHz), 10-25 Watt, 255 Channels D04RHF9PW4AN Model W4 (438-470 MHz), 10-25 Watt, 128 Channels D04RHF9PW5AN Model W5 (438-470 MHz), 10-25 Watt, 128 Channels...

  • Page 26

    Model Numbering, Charts, and Specifications ASTRO Digital Spectra UHF 20–40 Watt Model Chart Model Number Description D04QKH9PW3AN Model W3 (403-433 MHz), 20-40 Watt, 128 Channels D04QKF9PW4AN Model W4 (403-433 MHz), 20-40 Watt, 128 Channels D04QKF9PW5AN Model W5 (403-433 MHz), 20-40 Watt, 128 Channels...

  • Page 27

    Model Numbering, Charts, and Specifications xxvii ASTRO Digital Spectra UHF 20–40 Watt Model Chart (cont.) Model Number Description D04QKH9PW3AN Model W3 (403-433 MHz), 20-40 Watt, 128 Channels D04QKF9PW4AN Model W4 (403-433 MHz), 20-40 Watt, 128 Channels D04QKF9PW5AN Model W5 (403-433 MHz), 20-40 Watt, 128 Channels...

  • Page 28

    Model Numbering, Charts, and Specifications ASTRO Digital Spectra UHF 50–110 Watt Model Chart Model Number Description T04QLF9PW4AN Model W4 (403-433 MHz), 50-110 Watt, 128 Channels T04QLF9PW5AN Model W5 (403-433 MHz), 50-110 Watt, 255 Channels T04QLH9PW7AN Model W7 (403-433 MHz), 50-110 Watt, 255 Channels...

  • Page 29

    Model Numbering, Charts, and Specifications xxix ASTRO Digital Spectra UHF 50–110 Watt Model Chart (cont.) Model Number Description T04QLF9PW4AN Model W4 (403-433 MHz), 50-110 Watt, 128 Channels T04QLF9PW5AN Model W5 (403-433 MHz), 50-110 Watt, 255 Channels T04QLH9PW7AN Model W7 (403-433 MHz), 50-110 Watt, 255 Channels...

  • Page 30

    Model Numbering, Charts, and Specifications ASTRO Digital Spectra 800 MHz Model Chart Model Number Description D04UJF9PW3AN Model W3 (800 MHz), 35 Watt, 128 Channels D04UJF9PW4AN Model W4 (800 MHz), 35 Watt, 128 Channels D04UJF9PW5AN Model W5 (800 MHz), 35 Watt, 128 Channels...

  • Page 31

    Model Numbering, Charts, and Specifications xxxi ASTRO Digital Spectra Plus VHF 25–50 and 50–110 Watt Model Chart Model Number Description D04KKH9SW3AN Model W3 (146-174 MHz), 25-50 Watt, 512 Channels D04KKF9SW4AN Model W4 (146-174 MHz), 25-50 Watt, 128 Channels D04KKF9SW5AN Model W5 (146-174 MHz); 25-50 Watt, 128 Channels...

  • Page 32

    Model Numbering, Charts, and Specifications ASTRO Digital Spectra Plus VHF 25–50 and 50–110 Watt Model Chart (cont.) Model Number Description D04KKH9SW3AN Model W3 (146-174 MHz), 25-50 Watt, 512 Channels D04KKF9SW4AN Model W4 (146-174 MHz), 25-50 Watt, 128 Channels D04KKF9SW5AN Model W5 (146-174 MHz);...

  • Page 33

    Model Numbering, Charts, and Specifications xxxiii ASTRO Digital Spectra Plus 800 MHz Model Chart Model Number Description M04UGF9SW4AN Model W4 (800 MHz), 15 Watt, 128 Channels M04UGF9SW5AN Model W5 (800 MHz), 15 Watt, 128 Channels M04UGH9SW7AN Model W7 (800 MHz), 15 Watt, 512 Channels...

  • Page 34

    Model Numbering, Charts, and Specifications ASTRO Digital Spectra Plus 800 MHz Model Chart (cont.) Model Number Description M04UGF9SW4AN Model W4 (800 MHz), 15 Watt, 128 Channels M04UGF9SW5AN Model W5 (800 MHz), 15 Watt, 128 Channels M04UGH9SW7AN Model W7 (800 MHz), 15 Watt, 512 Channels...

  • Page 35

    Model Numbering, Charts, and Specifications xxxv VHF Radio Specifications GENERAL RECEIVER TRANSMITTER FCC Designations: AZ492FT3772 Frequency Range: Frequency Range: AZ492FT3773 Range 1: 136–162 MHz Range 1: 136–162 MHz Range 2: 146–174 MHz Range 2: 146–174 MHz Temperature Range: Operating: –30°C to +60°C Channel Spacing: 12.5 kHz, 25 kHz Rated Output Power:...

  • Page 36

    xxxvi Model Numbering, Charts, and Specifications UHF Radio Specifications GENERAL RECEIVER TRANSMITTER FCC Designations: AZ492FT4786 Frequency Range: Frequency Range: AZ492FT4787 Range 1: 403–433 MHz Range 1: 403–433 MHz Range 2: 438–470 MHz Range 2: 438–470 MHz Temperature Range: Range 3: 450–482 MHz Range 3: 450–482 MHz...

  • Page 37

    Model Numbering, Charts, and Specifications xxxvii 800 MHz Radio Specifications GENERAL RECEIVER TRANSMITTER FCC Designations: AZ492FT5759 Frequency Range: 851–869 MHz Frequency Range: AZ492FT5751 Repeater Mode: 806–824 MHz Channel Spacing: 12.5 kHz/20 kHz/25 kHz Talk-Around Mode: 851–869 MHz Temperature Range: Operating: –30°C to +60°C Input Impedance: 50 Ohm...

  • Page 38

    xxxviii This Page Intentionally Left Blank July 1, 2002 68P81076C25-C...

  • Page 39: Chapter 1 Introduction, General, Diagram

    This detailed level of service (component-level) is typical of some service centers, self-maintained customers, and distributors. Use this manual in conjunction with the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (Motorola part number 68P81076C20), which helps in troubleshooting a problem to a particular board.

  • Page 40: Notations Used In This Manual

    Introduction: Notations Used in This Manual Notations Used in This Manual Throughout the text in this publication, you will notice the use of warnings, cautions, and notes. These notations are used to emphasize that safety hazards exist, and care must be taken and observed.

  • Page 41: Chapter 2 General Overview, Introduction

    The ASTRO Digital Spectra radio comes in five models and are available in the following bands; VHF (136-174 MHz), UHF (403-470 MHz or 450-512 MHz), and 800 MHz (806-870 MHz).

  • Page 42: Analog Mode Of Operation, Astro Mode Of Operation, Control Head Assembly, Display (w3 Model)

    General Overview: Analog Mode of Operation Analog Mode of Operation When the radio is receiving, the signal comes from the antenna/antenna-switch on the power amplifier board to the front-end receiver assembly. The signal is then filtered, amplified, and mixed with the first local-oscillator signal generated by the voltage-controlled oscillator (VCO). The resulting intermediate frequency (IF) signal is fed to the IF circuitry on the RF board, where it is again filtered and amplified.

  • Page 43: Display (w9 Model), Vacuum Fluorescent Display Driver, Vacuum Fluorescent Voltage Source (w9 Model)

    General Overview: Control Head Assembly 2.4.3 Display (W9 Model) The control-head assembly for a W9 model has an 11-character, alphanumeric, vacuum fluorescent display. It needs three separate voltages to operate; the cathode needs 35 V to accelerate electrons to the anode; the grid needs 40 V to totally shut off current flow; the filament needs 3.8 Vac at 80mA. These voltages are obtained from the transformer on the display controller board.

  • Page 44: Vehicle Interface Ports, Power Supplies, Ignition Sense Circuits

    General Overview: Control Head Assembly 2.4.9 Vehicle Interface Ports The Vehicle Interface Ports (VIPs) allow the control head to activate external circuits and receive inputs from the outside world. In general, VIP outputs are used for relay control and VIP inputs accept inputs from external switches.

  • Page 45: Power Amplifier, Gain Stages, Power Control, Circuit Protection, Dc Interconnect

    General Overview: Power Amplifier Power Amplifier The power amplifier (PA) is a multi-stage, discrete-transistor RF amplifier consisting of the following: • Low-level power controlling stage • Drivers • Final amplifier • Directional coupler • Antenna switch • Harmonic filter 2.5.1 Gain Stages The first stage buffers the RF signal, filters harmonics, and acts as a variable amplifier.

  • Page 46: Front-end Receiver Assembly, Rf Board Basic, Voltage-controlled Oscillator, Vhf Radios

    General Overview: Front-End Receiver Assembly Front-End Receiver Assembly The receiver front-end consists of a preselector, a mixer circuit, and an injection filter. The receiver injection (1st local oscillator) comes from the VCO assembly through a coax cable. The injection filter is either fixed-tuned or tuned at the factory depending upon the bandsplit.

  • Page 47: Uhf And 800 Mhz Radios, Command Board, Astro Spectra Vocoder/controller Board

    General Overview: Command Board The VCO output is coupled to a transistor for amplification and for impedance buffering. The output of this stage passes through a low-pass filter where the signal is split into three paths. One path feeds back to the synthesizer prescaler; the other two provide injection for the RX and TX amplification strings.

  • Page 48: Radio Power, General

    General Overview: Radio Power The support-logic IC acts as an extension of the microcontrol unit by providing logic functions such as lower address latch, reset, memory address decoding, and additional control lines for the radio. The VOCON board controls a crystal-pull circuit to adjust the crystal oscillator frequency on the microcontrol unit, so that the E-clock harmonics do not cause interference with the receive channel.

  • Page 49: B+ Routing For Astro Spectra Vocon Board

    General Overview: Radio Power When the command board regulators are “on,” the 9.6-V output sources the command board and RF board circuits. The switched +5 V is routed to the VOCON board. See Figure 2-1. Control Command Board Battery Head Power Amp SWB+ UNSW...

  • Page 50

    2-10 General Overview: Radio Power Transistor Q206 controls solid-state power switch Q207, providing SWB+ to the encryption module (if equipped). The "SWB+" and "UNSWB+" encryption voltages both originate from pin 38 of J501 and are fed to the encryption module via J801. Port PL3 (5-V EN) on the SLIC and Q207 are under the control of the microcontroller unit (MCU), U204.

  • Page 51: Chapter 3 Theory Of Operation, Rf Board, General

    7. Schematics, Component Location Diagrams, and Parts Lists”. This detailed Theory of Operation will help isolate the problem. However, first use the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20) to troubleshoot the problem to a particular board.

  • Page 52: Figure 3-1. Prescaler Ic Block Diagram, Figure 3-2. Synthesizer Ic Block Diagram

    Theory of Operation: RF Board VREF CONT PNP BASE MULTI - MODULUS BASE PRESCALER 5V OUT LATCH S.F. VIN U601 MOSAIC PRESCALER S.F. BASE 300KHz 2ND L.O. CHARGE - PUMP S.F. OUT PHASE DETECTOR S.F. CAP DATA 2ND L.O. S.F. GND CLOCK 0 DET REF IN DATA OUT...

  • Page 53: Synthesizer, Reference Frequency Generation, First Vco Frequency Generation

    Theory of Operation: RF Board The reference oscillator generates the 16.8 MHz signal that serves as the reference for all radio frequency accuracy. It uses a proprietary temperature compensation circuit to keep the radio within its specified frequency tolerance. The receiver back-end uses the ABACUS II IC (U301) to demodulate all the way to baseband, starting from the first IF.

  • Page 54: Programmable Reference Divider

    Theory of Operation: RF Board The synthesizer generates a modulus control output which instructs the prescaler to divide by either P or P + 1 (that is, 255 or 256). When modulus control is low, the prescaler is dividing by P + l (256) and the A counter is running;...

  • Page 55: Phase Modulator, Loop Filter, Auxiliary Control Bits

    Theory of Operation: RF Board 3.1.2.4 Phase Modulator ASTRO radios use a dual-port modulation scheme. The nature of the synthesizer loop is to track out low-frequency errors. In order to enable low-frequency modulation, such as DPL, the reference signal is modulated with the same signal as the VCO. Effectively, this prevents the low-frequency error in the loop (DPL) from tracking out because the same error is on the reference signal.

  • Page 56: Second Vco, Power Distribution, Receiver Back-end, First If

    Theory of Operation: RF Board 3.1.2.7 Second VCO The second VCO is a grounded-gate, FET Colpitts oscillator. The resonator consists of a fixed inductor and a varactor. A potentiometer, R634, adjusts the negative voltage to the varactor. This adjustment is performed at board test to bring the phase detector output to the center of its linear region;...

  • Page 57: Abacus Ii Ic

    Theory of Operation: RF Board 3.1.3.2 ABACUS II IC Once in the ABACUS II IC (U301), the first IF frequency is amplified and then down converted to 450 kHz, the second IF frequency. At this point, the analog signal is converted into two digital bit streams by a sigma-delta A/D converter.

  • Page 58: Command Board, Microcontroller And Support Ics, Serial Input/output Ic

    Location Diagrams, and Parts Lists”. This detailed Theory of Operation will help isolate the problem to a particular component. However, first use the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual to troubleshoot the problem to a particular board.

  • Page 59: Power-up/-down Sequence

    Theory of Operation: Command Board 3.2.3 Power-Up/-Down Sequence Normally, switched B+ (SWB+) enters the command board from P502, pin 31. This voltage is derived from the battery A+ voltage which enters the control head through P502, pin 30. A power FET transistor, located in the control head (W5 and W7 models), provides the means of controlling the main power source via the control head’s on/off switch.

  • Page 60: Regulators, Reset Circuits

    3-10 Theory of Operation: Command Board 3.2.4 Regulators The regulator circuits include an unswitched +5 V (UNSW5V) discrete circuit, and the regulator/ power-control IC (RPCIC) that produces switched +5 V (U500, pin 14) and 9.6 V (U500, pin 17). The UNSW+5-V source is used by the RPCIC as a reference (U500, pin 20) for its switched + 5-V source.

  • Page 61: Serial Communications On The External Bus

    Theory of Operation: Command Board 3-11 The three inputs to the NOR gate (SW9.6-V, RPCIC EN, and RPCIC_EN delayed) must be at a logic low to enable the power-on reset (POR*) to a high logic state. During this power-up sequence, this reset is delayed approximately 170 ms after the B+ voltage is sensed.

  • Page 62: Synchronous Serial Bus (mosi), Received Audio, Microphone Audio, Synchronous Serial Bus (mosi)

    3-12 Theory of Operation: Command Board 3.2.7 Synchronous Serial Bus (MOSI) The synchronous serial bus is an internal bus used by the microcontroller for communicating with various ICs. The serial bus, called MOSI (master out/ slave in), is used to program the digital-to- analog (D/A) converter IC (U526), the serial-to-parallel shift register (U530) on the command board, and the ABACUS II IC (U301) on the RF board.

  • Page 63: Transmit Deviation, Rs-232 Line Driver, Flash Programming, Encryption Voltages

    Theory of Operation: Command Board 3-13 3.2.10 Transmit Deviation The analog transmit deviation (MAI) enters the VOCON board through P501, pin 39, and is converted to a digital format. The digital representation is processed and pre-emphasized by the DSP processor. The pre-emphasized digital bit stream is converted back to analog by the ADSIC device.

  • Page 64: Regulator And Power-control Ic

    3-14 Theory of Operation: Command Board 3.2.14 Regulator and Power-Control IC The regulator and power-control IC (RPCIC), U500, contains internal circuitry for the 9.6-V regulator and the switched +5-V regulator. Refer to Section 3.2.4, "Regulators," on page 3-10 for detailed theory of operation.

  • Page 65: Astro Spectra Vocon Board, General, Controller Section

    The controller section is the central interface between the various subsystems of the radio. It is very similar to the digital logic portion of the controllers on many existing Motorola radios. Its main task is to interpret user input, provide user feedback, and schedule events in the radio operation, which includes programming ICs, steering the activities of the DSP, and sending messages to the display through the control head.

  • Page 66

    3-16 Theory of Operation: ASTRO Spectra VOCON Board The SLIC (U206) performs many functions as a companion IC for the MCU. Among these are expanded input/output (I/O), memory decoding and management, and interrupt control. It also contains the universal asynchronous receiver transmitter (UART) used for the RS232 data communications.

  • Page 67: Vocoder Section

    Theory of Operation: ASTRO Spectra VOCON Board 3-17 3.3.3 Vocoder Section Refer to Figure 3-8 and your specific schematic diagram. The vocoder section of the VOCON board is made up of a digital signal processor (DSP) (U405), 24k x24 static-RAM (SRAM) (U414, U403, and U402), 256kB FLASH ROM (U404), and ABACUS II/DSP support IC (ADSIC) (U406).

  • Page 68: Rx Signal Path

    3-18 Theory of Operation: ASTRO Spectra VOCON Board When transmitting, the microphone audio is passed from the command board to the ADSIC, which incorporates an analog-to-digital (A/D) converter to translate the analog waveform to a series of data. The data is available to the DSP through the ADSIC parallel registers. In the converse way, the DSP writes speaker data samples to a D/A in the ADSIC, which provides an analog speaker audio signal to the audio power amplifier on the command board.

  • Page 69

    Theory of Operation: ASTRO Spectra VOCON Board 3-19 8KHz IRQB IRQB Command Board Interface D8-D23 J501-40 ADSIC DSP56001 A0-A2,A13-A15,RD*,WR* U406 U405 ABACUS II 2.4 MHz Receive Data Clock SCKR Interface 20 KHz RX Data Interrupt J501-6 48KHz TX Data Interrupt Data In J501-2 1.2 MHz Tx Data Serial Clock...

  • Page 70

    3-20 Theory of Operation: ASTRO Spectra VOCON Board The DSP accesses this data through its SSI port. This is a 6 port synchronous serial bus. It is used by the DSP for both transmit and receive data transferal, but only the receive functions will be discussed here.

  • Page 71: Tx Signal Path

    Theory of Operation: ASTRO Spectra VOCON Board 3-21 3.3.5 TX Signal Path The transmit signal path follows some of the same design structure as the receive signal path described in Section 3.3.4, "RX Signal Path," on page 3-18 (refer to Figure 3-10).

  • Page 72: Controller Bootstrap And Asynchronous Buses

    Figure 3-11) is an asynchronous serial communication bus, utilizing a Motorola proprietary protocol. It provides a means for the MCU to communicate with other hardware devices. In the ASTRO Digital Spectra radio, it communicates with hardware accessories connected to the accessory connector and the remote interface board.

  • Page 73

    VR208, Q211, and Q208 will trip, supplying Vpp to the FLASH devices, U205 and U404. The ASTRO Digital Spectra radio has an additional asynchronous serial bus which utilizes RS232 bus protocol. This bus utilizes the UART in the SLIC IC (U206). It consists of TX/RS232 (J501-43), RX/RS232 (J501-50), CTS/RS232 (J501-5), and RTS/RS232 (J501-42).

  • Page 74: Vocoder Bootstrap, Serial Peripheral Interface (spi) Bus, Controller Memory Map

    3-24 Theory of Operation: ASTRO Spectra VOCON Board 3.3.7 Vocoder Bootstrap The DSP has two modes of bootstrap: from program code stored in the FLASH ROM U404, or retrieving code from the host port. During normal modes of operation, the DSP executes program code stored in the FLASH ROM, U404.

  • Page 75: Figure 3-12. Controller Memory Mapping

    Theory of Operation: ASTRO Spectra VOCON Board 3-25 MAP 2 $0000 NON-MUX 32K COMMON External $0000 $1000 $0E00 Int EE $2000 $1000 F1 REGS $1060 $3000 INT RAM $4000 $1400 SLIC REG $5000 $1500 HOST PORT $6000 $1600 Ext RAM $1800 $7000 External...

  • Page 76: Vocoder Memory Map

    3-26 Theory of Operation: ASTRO Spectra VOCON Board The MCU executes program code stored in the FLASH ROMs. On a power-up reset, it fetches a vector from $FFFE, $FFFF in the ROMs and begins to execute code stored at this location. The external SRAM along with the internal 1Kx8 SRAM is used for temporary variable storage and stack space.

  • Page 77: Figure 3-13. Vocoder Memory Mapping

    Theory of Operation: ASTRO Spectra VOCON Board 3-27 $FFFF ADSIC Registers ADS Vectors $E000 $DFFF External ROM External ROM 16KB Physical 16KB Physical Banks Banks $00000-1FFFF $20000-3FFFF $A000 $9FFF Not Used $8000 $7FFF External External External U401 U402 U403 $2000 $1FFF $1000 $0FFF...

  • Page 78: Mcu System Clock, Dsp System Clock, Radio Power-up/power-down Sequence

    3-28 Theory of Operation: ASTRO Spectra VOCON Board The DSP program code is stored in the FLASH ROM, U404. During normal modes of operation, the DSP moves the appropriate program code into the three SRAMs (U401, U402, and U403) and internal RAM for execution.

  • Page 79: Vocon Board Signals

    Theory of Operation: ASTRO Spectra VOCON Board 3-29 During this process, the MCU does power diagnostics. These diagnostics include verifying the MCU system RAM, and verifying the data stored in the internal EEPROM, external EEPROM, and FLASH ROMs. The MCU queries the DSP for proper status and the results of DSP self tests. The DSP self tests include testing the system RAM, verifying the program code in ROM U404, and returning the ADSIC configuration register checksum.

  • Page 80

    3-30 Theory of Operation: ASTRO Spectra VOCON Board Table 3-3. VOCON Board Address Bus (HA) Pinouts U201 U202 U204 U205 U206 U210 U405 HA10 HA11 HA12 HA13 HA14 H1-In H8-In H4-Out HA15 H2-In H7-In K3-Out HA16 HA17 Table 3-4. VOCON Board Data Bus (D) Pinouts U402 U403 U404...

  • Page 81

    Theory of Operation: ASTRO Spectra VOCON Board 3-31 Table 3-4. VOCON Board Data Bus (D) Pinouts (Continued) U402 U403 U404 U405 U406 U414 Table 3-5. VOCON Board Data Bus (HD) Pinouts U201 U202 U204 U205 U206 U210 U405 68P81076C25-C July 1, 2002...

  • Page 82

    3-32 Theory of Operation: ASTRO Spectra VOCON Board Table 3-6. U204 (MCU) U204 Description To/From Pin # R260 PE1 B SENSE/LBAT/PWR DWN VR214 PE3 EMERG J901-4 PE6 SPKR COMMON R263 PE7 EXT SPKR R261 4XECLK (7.3726 MHz) U206-A3 PD0 BOOT DATA IN (RXD) J501-17 U206 PD1 BOOT DATA OUT (TXD) J501-18 U208...

  • Page 83

    Theory of Operation: ASTRO Spectra VOCON Board 3-33 Table 3-6. U204 (MCU) (Continued) U204 Description To/From Pin # PG4 ADSIC RST* U406-A8 PG3 ADSIC SEL* U406-B8 PG2 DSP RST* U405-G9 PG1 ROSC/PSC CE* J501-12 PG0 SYN SEL* J501-11 R/W* U405-D9 U206-B3 ECLK (1.8432 MHz) U206-A4...

  • Page 84

    3-34 Theory of Operation: ASTRO Spectra VOCON Board Table 3-7. U206 (SLIC) (Continued) U206 Description To/From Pin # R268 PJ5 OPT SEL2 (KEYLOAD*) R237 PJ6 VIP IN1 J501-24 PJ7 EMC EN* J801-10 POR* U409-2 HC11RST*/RESET* U204-E5 U201-31 U201-25 U202-22 U205-32 U210-32 R/W* U405-D9...

  • Page 85

    Theory of Operation: ASTRO Spectra VOCON Board 3-35 Table 3-7. U206 (SLIC) (Continued) U206 Description To/From Pin # MICEN J501-45 B+ CNTL U409-2 Q206B VIP OUT1 J501-22 CS3B EMC MAKEUP* J801-12 CS2B RAM SEL* U211-2 CS1B HEN* U405-E8 DISP EN*/LATCH SEL* J601-4 RED LED GRN LED...

  • Page 86

    3-36 Theory of Operation: ASTRO Spectra VOCON Board Table 3-8. VOCON U405 (DSP) (Continued) U405 Description To/From Pin # U406-J4 U406-K4 SCLK U204-G3 U406-C9 TXD/EMC RXD J801-3 RXD/EMC TXD J801-4 RESET/DSP RST* U204-H8 HACK* R409 HREQ* U204-H3 HEN* U206-J7 HR/W* U204-B6 Table 3-9.

  • Page 87

    Theory of Operation: ASTRO Spectra VOCON Board 3-37 Table 3-9. VOCON U406 (ADSIC) (Continued) U406 Description To/From Pin # SSW/EPS* U404-30 SCLK/SPI SCK U204-G5 J501-8 J801-9 SPO/MOSI J501-9 J801-8 U501-39 U501-40 VRO REFMOD J501-48 MODIN J501-49 RXD SRO 2.4 MHz U405-C5 RFS SC1 U405-B5...

  • Page 88: Astro Spectra Plus Vocon Board, General, Astro Spectra Plus Controller Section

    It is very similar to the digital logic portion of the controllers on many existing Motorola radios. Its main task is to interpret user input, provide user feedback, and schedule events in the radio operation, which includes programming ICs (Integrated Circuits), steering the activities of the DSP (Digital Signal Processor), and sending messages to the display through the control head.

  • Page 89: Astro Spectra Plus Vocoder Section

    Theory of Operation: ASTRO Spectra Plus VOCON Board 3-39 In addition to the SPI bus, the controller also maintains two asynchronous serial busses; the SB9600 bus and an RS232 serial bus. The SB9600 bus is for interfacing the controller section to different hardware option boards, some of which may be external to the radio.

  • Page 90

    3-40 Theory of Operation: ASTRO Spectra Plus VOCON Board When transmitting, the microphone audio is passed from the command board to the MC145483 CODEC (U402), which incorporates an analog-to-digital (A/D) converter to translate the analog waveform to a data stream. The data is made available to the DSP through the Serial Audio Port (SAP) of the Patriot IC.

  • Page 91: Astro Spectra Plus Rx Signal Path

    Theory of Operation: ASTRO Spectra Plus VOCON Board 3-41 3.4.4 ASTRO Spectra Plus RX Signal Path The vocoder processes all received signals digitally. This requires a unique back end from a standard analog radio. This unique functionality is provided by the ABACUS IC with the KRSIC (U200) acting as the interface to the DSP.

  • Page 92: Astro Spectra Plus Tx Signal Path

    3-42 Theory of Operation: ASTRO Spectra Plus VOCON Board The DSP accesses this data through its SSI port. The SSI port is used by the DSP for both transmit and receive data transferal, but only the receive functions will be discussed in this section. The KRSIC transfers the data to the DSP on the SRDB line at a rate of 1.2 MHz.

  • Page 93: Astro Spectra Plus Controller Bootstrap And Asynchronous Busses

    Figure 3-18) is an asynchronous serial communication bus, utilizing a Motorola proprietary protocol. It provides a means for the MCU to communicate with other hardware devices. In the ASTRO Digital Spectra Plus radio, it communicates with hardware accessories connected to the accessory connector and the remote interface board.

  • Page 94: Astro Spectra Plus Serial Peripheral Interface Bus, Astro Spectra Plus Mcu And Dsp System Clocks

    Theory of Operation: ASTRO Spectra Plus VOCON Board The ASTRO Digital Spectra Plus radio has an additional asynchronous serial bus, which utilizes the RS232 bus protocol. This bus utilizes the secondary UART in the Patriot IC (U300). It consists of TX / RS232 (J501-43), RX / RS232 (J501-50), CTS / RS232 (J501-5), and RTS / RS232 (J501-42).

  • Page 95: Astro Spectra Plus Voltage Regulators

    Theory of Operation: ASTRO Spectra Plus VOCON Board 3-45 3.4.9 ASTRO Spectra Plus Voltage Regulators The ASTRO Spectra Plus VOCON board contains two voltage regulators, a 3-V regulator (U411) and a 1.8-V regulator (U410). SW+5-V, which is routed to the ASTRO Spectra Plus VOCON board from the command board, drives the two regulators.

  • Page 96: Astro Spectra Plus Radio Power-up/power-down Sequence

    3-46 Theory of Operation: ASTRO Spectra Plus VOCON Board 3.4.10 ASTRO Spectra Plus Radio Power-Up/Power-Down Sequence The radio power-up sequence begins when the user actuates the control head's on/off switch. The control head then produces the switched B+ (SWB+) output voltage which is routed to the command board.

  • Page 97: Voltage Control Oscillator, Vhf Band, General, Dc Voltage Supplies

    Parts Lists”. This detailed Theory of Operation will help isolate the problem to a particular component. However, first use the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual to troubleshoot the problem to a particular board.

  • Page 98: Synthesizer Feedback, Rx Buffer Circuitry, Frequency Divider And Tx Buffer Circuitry, Uhf Band, General

    3-48 Theory of Operation: Voltage Control Oscillator The VCO output is coupled through C672 to Q645 to amplify the signal and provide load isolation for the VCO. The collector voltage of Q645 is normally about 5 Vdc. 3.5.1.4 Synthesizer Feedback The synthesizer locks the VCO on frequency by the VCO feedback to the prescaler IC on the RF board.

  • Page 99: Super Filter 8.6 V, Receive Mode (aux2* Low), Transmit Mode (aux2* High), Bandshift Circuit

    Theory of Operation: Voltage Control Oscillator 3-49 3.5.2.2 Super Filter 8.6 V Super-filtered 8.6 V enters the carrier board at J601-12, through an R-C filter, then on to the drain of Q9610 and the collector of Q9635. 3.5.2.3 VCO The oscillator consists of Q9610, the main transmission line (T-line), varactor bank (CR9616-9617, C9616-9617, L9616) and feedback capacitors (C9611-9613).

  • Page 100: Doubler, Synthesizer Feedback, Second Buffer, Receive/transmit Switch, Mhz Band, General, Super Filter 8.6 V

    3-50 Theory of Operation: Voltage Control Oscillator 3.5.2.9 Doubler The first buffer output is coupled to the input of the doubler by C5663. Q5660 doubles the drive frequency and increases power by approximately 3 dB as a result of the high and low impedances presented to its collector at the doubled frequency and drive frequency, respectively.

  • Page 101: Receive Mode-aux 1* And Aux 2* High, Transmit Mode-aux 1* High; Aux 2* Low

    Theory of Operation: Voltage Control Oscillator 3-51 The positive steering line connects to the cathodes of the four varactors and the negative steering line connects to the anodes. The negative line should be -4.0 ±0.3 V and the positive line can go as high as 9 V, allowing a difference of 15 to 16 V between the two.

  • Page 102: Second Buffer, K9.4 V Switch

    3-52 Theory of Operation: Voltage Control Oscillator Doubler-biasing differs between receive mode and transmit mode. For receive, R9677, R9678, and R9676 (in parallel to dissipate power) plus R9679 and R9680 bias the base of Q9675 to 0.7-V potential, if NO input RF power is applied to the base. For transmit mode, keyed 9.4 V is fed through CR9694 and another parallel resistor network R9674 and R9675.

  • Page 103: Receiver Front-end, Vhf Band, General, Theory Of Operation, Uhf Band

    “Chapter 7. Schematics, Component Location Diagrams, and Parts Lists”. This detailed Theory of Operation will help isolate the problem to a particular component. However, first use the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual to troubleshoot the problem to a particular board.

  • Page 104: Theory Of Operation, Mhz Band, General

    3-54 Theory of Operation: Receiver Front-End 3.6.2.2 Theory of Operation The factory-tuned ceramic preselector filter accommodates RF input frequencies ranging from 438 to 470 MHz (Range 2), 450 to 482 MHz (Range 3), or 482 to 512 MHz (Range 4). The injection filter is tuned to pass frequencies from 549 to 580 MHz for Range 2, 559 to 592 MHz for Range 3, or 592 to 622 MHz for Range 4.

  • Page 105: Power Amplifiers, Vhf Band Power Amplifiers, High-power Amplifier, Transmitter

    Lists”. This detailed Theory of Operation will help isolate the problem to a particular component. However, first use the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual to troubleshoot the problem to a particular board. 3.7.1 VHF Band Power Amplifiers 3.7.1.1 High-Power Amplifier...

  • Page 106: Antenna Switch And Harmonic Filter

    3-56 Theory of Operation: Power Amplifiers The final stage output network serves the dual purpose of impedance matching and power combining of the two final devices. R3872 and R3873 help balance the load impedances presented to the collectors of the final devices. Filtered A+ is routed to the final amplifier devices via the current sense resistor R3841, the ferrite bead L3881, and the coil L3880.

  • Page 107: Power Control Circuitry

    Theory of Operation: Power Amplifiers 3-57 3.7.1.1.3 Power Control Circuitry Command Board Circuitry Inside U500, the Regulator Power Control IC (see Figure 3-20) is an operational amplifier that has four inverting inputs, and one non-inverting input (at pin 44) which is the reference input for the entire power control loop of the power amplifier.

  • Page 108

    3-58 Theory of Operation: Power Amplifiers Control Voltage Limiter R3807 and R3808 form a voltage divider that connects to control voltage drive. The output of this voltage divider is connected to the control-voltage-limit input (pin 4) of the RPCIC. If the voltage at this input reaches 3.2 V, then the control voltage will be clamped to a maximum value.

  • Page 109: Watt Power Amplifier

    Theory of Operation: Power Amplifiers 3-59 Temperature Sensing The temperature-sensing circuit of the PA works with the RPCIC to protect the PA devices from excessively high temperatures. On the PA board, this circuit (formed by resistors R3916, R3841, and thermistor RT3842), provides a temperature dependent voltage to the RPCIC via J1 pin 6. As the PA temperature increases, the resistance of RT3842 decreases, causing the voltage at pin 6 to increase.

  • Page 110

    3-60 Theory of Operation: Power Amplifiers Final Stage The final device is a 3- to 33-Watt device and is driven by the driver through a low-pass matching circuit that consists of C3815, C3816, C3817, L3811, C3819, C3821, C3822, C3823 and associated transmission lines.

  • Page 111

    Theory of Operation: Power Amplifiers 3-61 The power control loop is controlled by the microprocessor U204 on the VOCON board. Through the SLIC IC U206, the microprocessor enables the RPCIC by pulling TX PA ENABLE (U500 pin 33) low while the radio synthesizer is locked (U500 pin 35). U520 writes data to a digital-to-analog converter, U502, to change and control the power-set voltage from pin 10 of U502 to pin 6 of U500.

  • Page 112

    3-62 Theory of Operation: Power Amplifiers The collector currents of the 25/10-Watt amplifier is monitored by sensing the voltage across R3875. CURRENT SENSE + connects to one end of R3875; CURRENT SENSE - connects to the other end. These lines connect to the command board on U500, Pins 37 and 38, respectively. If the TX CURRENT LIMIT is set for 1.5 V, then the voltage difference between U500, Pins 37 and 38 must be 0.

  • Page 113: Watt Power Amplifiers, Transmitter

    Theory of Operation: Power Amplifiers 3-63 3.7.1.3 50-Watt Power Amplifiers 3.7.1.3.1 Transmitter The 50-Watt ASTRO Spectra power amplifiers (PA's) are discussed in the following text. A block diagram of the circuit is shown in Figure 3-22. CONTROLLED FINAL DIRECTIONAL TX INJECTION E3851 TX BUFFER PREDRIVER...

  • Page 114

    3-64 Theory of Operation: Power Amplifiers Final Stage The final device is a 12- to 75-Watt device and is driven by the driver through a low pass matching circuit that consists of C3850 through C3854 and associated transmission lines. Base network, L3852, L3853, and R3851, provide the zero-DC bias required by the final device's Class C operation.

  • Page 115

    Theory of Operation: Power Amplifiers 3-65 3.7.1.3.3 Power Control Circuitry Command Board Circuitry Inside U500, the Regulator Power Control IC (Figure 3-23), is an operational amplifier that has four inverting inputs, and non-inverting input at pin 44 which is the reference input for the entire power control loop of the power amplifier.

  • Page 116

    3-66 Theory of Operation: Power Amplifiers Control Voltage Limiter R3807 and R3808 form a voltage divider that connects to control voltage drive. The output of this voltage divider is connected to the control-voltage-limit input, pin 4 of the RPCIC. If the voltage at this input reaches 3.2 V, then the control voltage will be clamped to a maximum value.

  • Page 117

    Theory of Operation: Power Amplifiers 3-67 Temperature Sensing The temperature-sensing circuit of the PA works with the RPCIC to protect the PA devices from exclusively high temperatures. On the PA board, this circuit, formed by resistors R3878 thru R3880 and thermistor RT3877, provides a temperature-dependent voltage to the RPCIC via P0853, pin 7. As the PA temperature increases, the resistance of RT3875 decreases, causing the voltage at pin 7 to increase.

  • Page 118: Uhf Band Power Amplifiers, High-power Amplifier, Transmitter

    3-68 Theory of Operation: Power Amplifiers 3.7.2 UHF Band Power Amplifiers 3.7.2.1 High-Power Amplifier 3.7.2.1.1 Transmitter The high-power Spectra amplifier is discussed in the following text. A block diagram of the circuit is shown in. FINAL AMPLIFIER Q5875 25C29 ANTENNA HARMONIC DIRECTIONAL SWITCH...

  • Page 119

    Theory of Operation: Power Amplifiers 3-69 Final Stage The final amplifier stage is the parallel combination of two 25-Watt input to 75-Watt output RF transistors. The matching network from the collector of the driver device Q5851 to the bases of the final devices Q5875 and Q5876 utilizes transmission lines as part of a combination matching network and power splitter.

  • Page 120: Figure 3-25. Rpcic Block Diagram

    3-70 Theory of Operation: Power Amplifiers The power control loop is controlled by the microprocessor U204 on the VOCON board. Through the SLIC IC U206, the microprocessor enables the RPCIC by pulling TX PA ENABLE (U500 pin 33) low while the radio synthesizer is locked (U500 pin 35). U520 writes data to a digital-to-analog converter, U502, to change and control the power-set voltage from pin 10 of U502 to pin 6 of U500.

  • Page 121

    Theory of Operation: Power Amplifiers 3-71 The collector current of the high-power amplifier is monitored by sensing the voltage across R5875. CURRENT SENSE + connects to one end of R5875; CURRENT SENSE - connects to the other end. These lines connect to the command board on U500 pins 37 and 38, respectively. If the TX CURRENT LIMIT is set for 1.5 V, then the voltage difference between U500 pins 37 and 38 must be 0.1 V before the current through R5875 is reduced.

  • Page 122: Transmitter, Watt Power Amplifier

    3-72 Theory of Operation: Power Amplifiers 3.7.2.2 40-Watt Power Amplifier 3.7.2.2.1 Transmitter The 40-Watt ASTRO Spectra power amplifier is discussed in the following text. Transmit Low Level Amplifier (LLA) NOTE: The minimum input drive level to the PA into P5850 is 30 mW. Refer to the synthesizer section if input drive is less than 30 mW.

  • Page 123

    Theory of Operation: Power Amplifiers 3-73 3.7.2.2.2 Antenna Switch and Harmonic Filter Antenna Switch The antenna switch's impedance inverter circuit, made up of C5923 and L5921, takes the place of a quarter-wave microstrip line. During transmission, Keyed 9.4 V forward-biases CR5921, producing low impedance on CR5921's anode and high impedance on the C5923/L5921 node.

  • Page 124

    3-74 Theory of Operation: Power Amplifiers 3.7.2.2.3 Power Control Circuitry Command Board Circuitry Inside U500, the Regulator Power Control IC (Figure 3-26), is an operational amplifier that has four inverting inputs, and one non-inverting input (at pin 44) which is the reference input for the entire power control loop of the power amplifier.

  • Page 125

    Theory of Operation: Power Amplifiers 3-75 Control Voltage Limiter R5807 and R5808 form a voltage divider that connects to control voltage drive. The output of this voltage divider is connected to the control-voltage-limit input ( pin 4) of the RPCIC. If the voltage at this input reaches 3.2 V, then the control voltage will be clamped to a maximum value.

  • Page 126

    3-76 Theory of Operation: Power Amplifiers Temperature Sensing The temperature-sensing circuit of the PA works with the RPCIC to protect the PA devices from excessively high temperatures. On the PA board, this circuit, formed by resistors R5878, R5876, R5877, and thermistor RT5875, provides a temperature-dependent voltage to the RPCIC via P0853, pin 7.

  • Page 127: Mhz Band Power Amplifiers, And 35-watt Amplifiers, Transmitter

    Theory of Operation: Power Amplifiers 3-77 3.7.3 800 MHz Band Power Amplifiers 3.7.3.1 15- and 35-Watt Amplifiers 3.7.3.1.1 Transmitter The 15-Watt and 35-Watt ASTRO Spectra power amplifiers are discussed in the following text. Transmit Buffer The PA receives 18 to 23 dBm (60 to 200 mW) at the transmit injection (TX INJ) coax. The first stage, TX BUFFER, uses adaptive biasing which varies the base voltage inversely proportional to the input drive level.

  • Page 128

    3-78 Theory of Operation: Power Amplifiers Final Stage (35-Watt Only) On the 15-Watt radio, the transmit RF signal from U9850, pin 5, is applied to the 50-ohm microstrip directional coupler. On the 35-Watt radio, the transmit RF signal is applied to the emitter of the final power amplifier Q9880 through the coupling capacitor C9856, the 50-ohm quarter-wave matching transmission line, and the matching capacitors C9875 and C9876.

  • Page 129

    Theory of Operation: Power Amplifiers 3-79 NOTE: When removing any of the discrete coils, take care to avoid leaching the plate capacitor metallization. Removal of the entire hybrid is best accomplished by heating hybrid/PC board assembly with a heat gun or heat blower until solder joint reflows. 3.7.3.1.3 Power Control Circuitry Command Board Circuitry Inside U500, the Regulator Power Control IC...

  • Page 130

    3-80 Theory of Operation: Power Amplifiers Power Module Control Voltage Limiter R9562 and R9563 connect in series to the emitter of Q9500. The ratio of R9563 and R9562 feed a portion of the control voltage (U9850, Pins 2 and 3) to U500, pin 4. When pin 4 exceeds 3.2 V, the output of the control op-amp (U500, pin 42) is reduced.

  • Page 131: Temperature Sensing

    Theory of Operation: Power Amplifiers 3-81 3.7.3.1.4 Temperature Sensing When the radio is keyed, K9.4-V is applied to pin 5 of the PA connector and on one side of thermistor RT9560. As the temperature increases, the resistance of RT9560 decreases, creating more voltage across R9561.

  • Page 132

    3-82 Theory of Operation: Power Amplifiers This Page Intentionally Left Blank July 1, 2002 68P81076C25-C...

  • Page 133: Chapter 4 Troubleshooting Procedures, Astro Spectra Procedures, Handling Precautions

    Chapter 4 Troubleshooting Procedures ASTRO Spectra Procedures This section will aid you in troubleshooting a malfunctioning ASTRO Digital Spectra radio. It is intended to be detailed enough to localize the malfunctioning circuit and isolate the defective component. NOTE: Refer to “4.2 ASTRO Spectra Plus Procedures”...

  • Page 134: Voltage Measurement And Signal Tracing, Power-up Self-check Errors

    In most situations, the problem circuit may be identified using a dc voltmeter, RF millivoltmeter, and oscilloscope (preferably with 100 MHz bandwidth or more). The “Recommended Test Equipment, Service Aids, and Tools” section in the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20) outlines the recommended tools and service aids which would be useful.

  • Page 135: Power-up Sequence

    Troubleshooting Procedures: ASTRO Spectra Procedures Table 4-1. Power-Up Self-Check Error Codes (Continued) Error Description Troubleshooting Chart Code 01/92 Internal EEPROM checksum failure Chart C.10 (p. 9) 02/81 DSP ROM checksum failure Chart C.12 (p. 10) 02/82 DSP RAM 1 failure Chart C.15 (p.

  • Page 136

    Troubleshooting Procedures: ASTRO Spectra Procedures - Set the EMC wake-up line high. 7. Begin power-up self-tests. 8. Begin RAM tests: - External RAM ($1800-3FFF). - Internal RAM ($1060-$1300). - External RAM ($0000-$0DFF). - Display 01/88 if failure. The radio will get stuck here if the internal RAM is defective. The radio uses the internal RAM for stack.

  • Page 137: Rf Board Troubleshooting, Display Flashes "fail

    Troubleshooting Procedures: ASTRO Spectra Procedures 12. Power-up the EMC (if it is enabled in the codeplug). 13. Turn off the green LED. 14. Start up operating system. 15. Display for one second: - “SELF TEST” for the W3, model. - “SELF CHK” for the W4, W5, and W7 models. - “SELF CHECK”...

  • Page 138: Incorrect Values At U602, Pin 19

    Troubleshooting Procedures: ASTRO Spectra Procedures 4. Check the negative steering line, J601, pin 4. If correct, continue with the following checks. 5. Check the positive steering line, J601, pin 1 or 2 for positive voltage between 1.0 and 8.0 V. If not correct, go to “Incorrect Voltage at Positive Steering Line”;...

  • Page 139: Incorrect Values At U602 Pin 25 (modulus Control), Incorrect Voltage At Positive Steering Line

    Troubleshooting Procedures: ASTRO Spectra Procedures 4.1.4.1.2 Incorrect Values at U602 Pin 25 (MODULUS CONTROL) If the frequency is not 6.25 kHz (or 5.0 kHz for VHF), verify the proper VCO pin-shift logic. See VCO block diagram (Figure 4-1) for pin-shift logic. Also, check the VCO feedback for approximately -10 to 5 dBm at proper VCO frequency.

  • Page 140: Second Vco Checks, Troubleshooting The Back-end

    Troubleshooting Procedures: ASTRO Spectra Procedures At 450 MHz, there are 72,000 counts of 2.22 nanoseconds each per reference period. When modulus control (MCT) is high, the VCO output is prescaled by 255 (see the diagram below). The output frequency of the prescaler is 1.765 MHz which corresponds to a period, per-cycle, of 567 nanoseconds.

  • Page 141: Standard Bias Table

    Troubleshooting Procedures: ASTRO Spectra Procedures 4.1.5 Standard Bias Table Table 4-4, below, outlines some standard supply voltages and system clocks which should be present under normal operation. These should be checked as a first step to any troubleshooting procedure. Table 4-4. Standard Operating Bias Signal Name Nominal Value Tolerance...

  • Page 142: Astro Spectra Plus Procedures, Astro Spectra Plus Power-up Self-check Errors

    Troubleshooting Procedures: ASTRO Spectra Plus Procedures ASTRO Spectra Plus Procedures This section will aid you in troubleshooting a malfunctioning ASTRO Digital Spectra Plus radio. It is intended to be detailed enough to localize the malfunctioning circuit and isolate the defective component.

  • Page 143: Astro Spectra Plus Power-up Self-check Diagnostics And Repair

    Troubleshooting Procedures: ASTRO Spectra Plus Procedures 4-11 Table 4-5. ASTRO Spectra Plus Power-Up Self-Check Error Codes (Continued) Error Code Description Corrective Action 02/88 DSP RAM Fatal Error --Note: Not a checksum Turn radio off, then on error 02/90 General DSP Hardware Failure (DSP startup Turn radio off, then on message not received correctly) 09/10...

  • Page 144: Astro Spectra Plus Standard Bias Table

    4-12 Troubleshooting Procedures: ASTRO Spectra Plus Procedures Error Code 09/10 Cycle power to the radio. If this fails then follow instructions as per troubleshooting chart C.32 Error Code 09/90 Cycle power to the radio. If this fails then follow instructions as per troubleshooting chart C.32 4.2.3 ASTRO Spectra Plus Standard Bias Table...

  • Page 145: Vco Procedures, Vhf Band, Vco Hybrid Assembly, Out-of-lock Condition

    Troubleshooting Procedures: VCO Procedures 4-13 VCO Procedures This section provides band-specific troubleshooting procedures for the VCO. 4.3.1 VHF Band Use these instructions along with the Theory of Operation, the block diagram, and the schematic to help isolate failures: first, to the individual circuits, and finally, to the failing piece part. 4.3.1.1 VCO Hybrid Assembly The VCO hybrid substrate is glued to the carrier board.

  • Page 146

    4-14 Troubleshooting Procedures: VCO Procedures If the AUX 1* and AUX 2* voltages are correct and the synthesizer feedback level is correct but an out-of-lock condition persists, troubleshoot the synthesizer. SF 8.6 AUX 1 AUX 2 J601-12 J601-9 J601-11 J601-2 PIN DIODE BIAS BIAS...

  • Page 147: No Or Low Output Power (tx Or Rx Injection), No Or Low Modulation, Uhf Band

    4.3.1.3 No or Low Output Power (TX or RX Injection) Use the test cables listed in the Service Aids section in the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20). Measure the power at the synthesizer feedback port - if it is not within the range specified in the block diagram, troubleshoot the first buffer.

  • Page 148: Out-of-lock Condition, No Or Low Output Power (tx Or Rx Injection)

    4-16 Troubleshooting Procedures: VCO Procedures 4.3.2.2 Out-of-Lock Condition The probable cause of an out-of-lock condition is a failure in the synthesizer circuit. (See Section 4.1.4.2 Review of Synthesizer Fundamentals on page 4-7.) If the voltages on the AUX 1*, AUX 2*, or -8V lines at P0601 do not conform to the values shown in Figure 4-2, check the pin shift circuitry on...

  • Page 149: No Or Low Modulation

    Troubleshooting Procedures: VCO Procedures 4-17 4.3.2.4 No or Low Modulation Under standard test conditions with a 1 kHz tone injected and 4.5 kHz deviation, there should be 700 mV (RMS) ±20% present on P0601-10. If this level is not present, troubleshoot the modulation circuit on the carrier board and then troubleshoot the audio circuitry.

  • Page 150: Mhz Band, Vco Hybrid Assembly, Out-of-lock Condition

    4-18 Troubleshooting Procedures: VCO Procedures 4.3.3 800 MHz Band Use these instructions along with the Theory of Operation, the block diagram, and the schematic to help isolate failures, first, to the individual circuits, and finally to the failing piece part. 4.3.3.1 VCO Hybrid Assembly The VCO hybrid substrate is glued to the carrier board.

  • Page 151

    4.3.3.3 No or Low Output Power (TX or RX Injection) Use the test cables listed in the “Service Aids” in the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20). Measure the power at the synthesizer feedback port-if it is not within the range specified in the block diagram, troubleshoot the first buffer.

  • Page 152: Receiver Front-end (rxfe), Vhf Band, Uhf Band, Mhz Band, Receiver Front-end (rxfe)

    4-20 Troubleshooting Procedures: Receiver Front-End (RXFE) Receiver Front-End (RXFE) This section provides band-specific troubleshooting procedures for the receiver front-end. 4.4.1 VHF Band This information will help you troubleshoot the Spectra radio. Use this information, along with the Theory of Operation, to diagnose and isolate the cause of failures. The principle tools needed to troubleshoot a circuit to the component level are the schematic and the Theory of Operation.

  • Page 153: Power Amplifier Procedures, Vhf Band, High-power Amplifier, General Troubleshooting And Repair Notes

    PA kit is ordered a filter kit comes with the PA kit. After a PA board is replaced, or if any power control circuitry components are replaced, readjust the power according to instructions in the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20).

  • Page 154

    PA or command board. This may be checked using a PC and RSS software. Alternatively, front panel programming may be used. Please refer to the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20) for programming instructions.

  • Page 155

    Troubleshooting Procedures: Power Amplifier Procedures 4-23 If it is verified that both power set and current limit are not related to the power problem, then the synthesizer output must be checked. A milliwatt meter connected to the TX injection cable should indicate at least 10 mW of injection power during key-up.

  • Page 156

    4-24 Troubleshooting Procedures: Power Amplifier Procedures Table 4-8. Power Control DC Voltage Chart (Continued) RX MODE TX MODE LOCATION COMMENTS Thermister Buffer in 5-V Sense Input (follows pin 20 ±0.1 V) 5-V Current Limit (limits at 5.7 V) 5-V Series Pass Drive (6.4 at max current) 9.6-V Sense Input 5-V Reg.

  • Page 157: Pa Functional Testing

    Troubleshooting Procedures: Power Amplifier Procedures 4-25 Table 4-8. Power Control DC Voltage Chart (Continued) RX MODE TX MODE LOCATION COMMENTS Ground Control AMP Output (Approx 1/2-V Control) Loop Integrator Capacitor Control AMP Reference Q0500E 13.0 13.0 A+ - CR0500 Drop Q0501C 12.3 12.3...

  • Page 158

    4-26 Troubleshooting Procedures: Power Amplifier Procedures Testing Low-Level Amplifier (LLA) Circuitry Proper operation of the LLA can be checked by monitoring the voltage across resistor R3804. The voltage should measure in the range of 0.4 V to 1.0 V, depending on the value of control voltage. A 0.4-V reading corresponds to a low control voltage (4 to 5 V) and a 1.0-V reading corresponds to a high control voltage (up to control voltage limit).

  • Page 159

    Troubleshooting Procedures: Power Amplifier Procedures 4-27 Troubleshooting the Driver Stage (Q3805) • Make sure A+ is at the collector. • Check for shorts and/or opens in the matching circuitry. Also look for faulty components (cracked parts or parts not properly soldered). •...

  • Page 160: Power Control And Protection Circuitry

    4.5.1.1.3 Power Control and Protection Circuitry Localizing Problems to a Circuit Power leveling and current limiting are set to values detailed in the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20). These values will vary from unit to unit, depending on the unique variations of each unit.

  • Page 161: General Troubleshooting And Repair Notes, Watt Power Amplifier

    NOTE: If any part of the power leveling circuitry is replaced, perform the power set procedure. See the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20) for details.

  • Page 162

    Troubleshooting Procedures: Power Amplifier Procedures After a PA board is replaced, or if any power control circuitry components are replaced, readjust the power according to instructions in the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20).

  • Page 163

    Troubleshooting Procedures: Power Amplifier Procedures 4-31 3. Apply the required input power via an adapter cable. For this application, non 'N' type connectors are acceptable. A+ TO COMMAND BOARD A+ TO COMMAND BOARD CURRENT SENSE + CURRENT SENSE - CONTROL VOLTAGE LIMIT FEMALE RECEPTACLE CONNECTOR W 100 MIL SPACING MATES TO P853...

  • Page 164

    4-32 Troubleshooting Procedures: Power Amplifier Procedures Table 4-11. Power Control DC Voltage Chart (Continued) RX MODE TX MODE LOCATION COMMENTS 10.8 13.8 16.6 10.4 13.4 16.2 A+ to Command Board 9.6-V Supply from Command Board 10.8 13.1 15.9 Current Sense - (voltage delta 150 mV) U0500 Ground Control AMP Input...

  • Page 165

    Troubleshooting Procedures: Power Amplifier Procedures 4-33 Table 4-11. Power Control DC Voltage Chart (Continued) RX MODE TX MODE LOCATION COMMENTS N.C. 13.6 13.6 N.C. — — — — — — 9.6-V Programming (N.C.) — — — — — — 9.6-V Programming (N.C.) —...

  • Page 166: Localizing Problems

    4-34 Troubleshooting Procedures: Power Amplifier Procedures Table 4-12. Antenna Switch DC Voltage Chart TYPICAL TX LOCATION TYPICAL RX NO PRE- COMMENTS DRIVE ANODE CR3920 CATHODE CR3921 ANODE CATHODE — — ANODE <0.8 CR3922 CATHODE — — 4.5.1.2.3 Localizing Problems Failure locations often can be determined by externally measured symptoms. Basic symptoms are noted below with probable failure locations.

  • Page 167: Isolating Failures

    Troubleshooting Procedures: Power Amplifier Procedures 4-35 4.5.1.2.4 Isolating Failures Methods of analyzing individual stages of the Power Amplifiers are detailed below. Most of the stages are Class C and must be analyzed under relatively high RF power levels. Generators capable of such levels may not be available in all service shops, therefore the tests below are arranged in order of ascending power.

  • Page 168

    NOTE: When replacing either the driver or final device, apply thermal compound on the heatsink surface. Torque the screws to the correct value; see the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20).

  • Page 169

    4.5.1.2.5 Power Control and Protection Circuitry Localizing Problems to a Circuit Power leveling and current limiting are set to values detailed in the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20). These values will vary from unit to unit, depending on the unique variations of each unit.

  • Page 170

    After a PA board is replaced, or if any power control circuitry components are replaced, readjust the power according to instructions in the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20).

  • Page 171

    Troubleshooting Procedures: Power Amplifier Procedures 4-39 4.5.1.3.2 PA Functional Testing To test the PA assembly for proper operation, perform the following steps: 1. Disassemble the PA assembly from the radio, leaving the power cable connected to the rear connector. Replace the PA shield and cover. Disconnect the coax connectors and the ribbon cable.

  • Page 172

    4-40 Troubleshooting Procedures: Power Amplifier Procedures 8. If no failure is located from the previous checks, troubleshoot the power control circuitry. A+ TO COMMAND BOARD A+ TO COMMAND BOARD CURRENT SENSE + CURRENT SENSE - CONTROL VOLTAGE LIMIT FEMALE RECEPTACLE CONNECTOR W 100 MIL SPACING MATES TO P853 REGULATED 9.6V...

  • Page 173

    Troubleshooting Procedures: Power Amplifier Procedures 4-41 Table 4-15. Power Control DC Voltage Chart (Continued) RX MODE TX MODE LOCATION COMMENTS Control AMP Input (not used) Control Voltage Limit (cutback at 3.3 V) N.C. Power Set from D-A (max power at 1.5 V) Power Set Buffer Out Coupler Buffer Out Forward Detect Voltage...

  • Page 174

    4-42 Troubleshooting Procedures: Power Amplifier Procedures Table 4-15. Power Control DC Voltage Chart (Continued) RX MODE TX MODE LOCATION COMMENTS 10.8 13.6 16.5 10.0 13.0 16.0 Decoupled A+ TX PA Enable (from U520-25) Control AMP one-shot Lock (5-V of Synth Out of Lock) Control AMP one-shot 10.8 13.6...

  • Page 175

    Troubleshooting Procedures: Power Amplifier Procedures 4-43 3. Power Intermittently Low (or Zero) and Current Less than 1 A. When Power Drops - Check LLA stage. 4. Power Zero and Current Greater Than 5 A. - Check harmonic filter, antenna switch, and matching circuits beyond final stage. 5.

  • Page 176

    4-44 Troubleshooting Procedures: Power Amplifier Procedures If the above DC bias conditions are correct, check to see if the LLA is providing drive power to the pre-driver, Q3804. Do so by checking Q3804's collector current under normal drive conditions, as follows: •...

  • Page 177

    4.5.1.3.5 Power Control and Protection Circuitry Localizing Problems to a Circuit Power leveling and current limiting are set to values detailed in the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20). These values will vary from unit to unit, depending on the unique variations of each unit.

  • Page 178

    P0853, pin 9, should measure approximately 1.3 V. NOTE: If any part of the power leveling circuitry is replaced, perform the power set procedure. See the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20) for details.

  • Page 179: Uhf Band, High-power Amplifier, General Troubleshooting And Repair Notes

    PA kit is ordered a filter kit comes with the PA kit. After a PA board is replaced, or if any power control circuitry components are replaced, readjust the power according to instructions in the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20).

  • Page 180

    4-48 Troubleshooting Procedures: Power Amplifier Procedures Begin troubleshooting by connecting an RF power meter and appropriate power load to the antenna connector. Connect the control cable and the power cable. Make sure the ignition sense lead is also connected to the positive lead of the power supply. Note that a regulated DC power supply capable of at least 30 A.

  • Page 181

    Troubleshooting Procedures: Power Amplifier Procedures 4-49 Table 4-17. Power Control DC Voltage Chart RX MODE TX MODE LOCATION COMMENTS Control Voltage Limit 10.0 Drive Voltage 10.8 13.6 16.5 10.0 13.0 16.0 Current Sense + Keyed 9.4 10.8 13.6 16.5 10.0 13.0 16.0 A+ to Command Board...

  • Page 182

    4-50 Troubleshooting Procedures: Power Amplifier Procedures Table 4-17. Power Control DC Voltage Chart (Continued) RX MODE TX MODE LOCATION COMMENTS 5-V Series Pass Drive (6.4 at max current) 9.6-V Sense Input 5-V Reg. Compensation Capacitor N.C. 5-V Reference Input (UNSW5-V) 9.6-V Reg.

  • Page 183

    PA or command board. This may be checked using a PC and RSS software. Alternatively, front panel programming may be used. Please refer to the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20) for programming instructions.

  • Page 184

    4-52 Troubleshooting Procedures: Power Amplifier Procedures Methods of analyzing individual stages of the power amplifiers are detailed below. Most of the stages are Class-C and must be analyzed under relatively high RF power levels. The following information should help in isolation and repair of the majority of transmitter failures. Testing Low-Level Amplifier (LLA) Circuitry Proper operation of the LLA can be checked by monitoring the voltage across resistor R5805.

  • Page 185

    Troubleshooting Procedures: Power Amplifier Procedures 4-53 NOTE: If it is necessary to replace Q5803, use a hot-air blower to remove and replace the part. It is important that the replacement device's case be properly soldered to its heatsink. Do so by flowing a small bead of solder around the rim of the device while it is clamped in the hot-air soldering device.

  • Page 186

    4.5.2.1.3 Power Control and Protection Circuitry Localizing Problems to a Circuit Power leveling and current limiting are set to values detailed in the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20). These values will vary from unit to unit, depending on the unique variations of each unit.

  • Page 187

    Troubleshooting Procedures: Power Amplifier Procedures 4-55 Control-Voltage-Limit Circuitry Test Disconnect J5901 (transmitter injection) from the PA input. With all other connections in normal condition, key the transmitter and monitor the control voltage at J1 pin 2. If the voltage exceeds 10.0 V, troubleshoot the control voltage limit circuitry.

  • Page 188

    NOTE: If any part of the power leveling circuitry is replaced, perform the power set procedure. See the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20) for details.

  • Page 189

    PA kit is ordered, a filter kit comes with the PA kit. After a PA board is replaced, or if any power control circuitry components are replaced, readjust the power according to instructions in the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20).

  • Page 190

    4-58 Troubleshooting Procedures: Power Amplifier Procedures 8. If no failure is located from the previous checks, troubleshoot the power control circuitry. Table 4-19. DC Voltages and Input Power Chart CONTROL POWER IN Test Keyed 9.4 V 9.6 V VOLTAGE A+ .V (mW) DRIVE Transmit...

  • Page 191

    Troubleshooting Procedures: Power Amplifier Procedures 4-59 Table 4-20. Power Control DC Voltage Chart RX MODE TX MODE LOCATION COMMENTS P0853 — — — — — — Key (no pin or wire) Control Voltage Limit 10.0 Drive Voltage 10.8 13.6 16.5 10.0 13.0 16.0...

  • Page 192

    4-60 Troubleshooting Procedures: Power Amplifier Procedures Table 4-20. Power Control DC Voltage Chart (Continued) RX MODE TX MODE LOCATION COMMENTS 5-V Current Limit (limits at 5.7 V) 5-V Series Pass Drive (6.4 at max current) 9.6-V Sense Input 5-V Reg. Compensation Capacitor N.C.

  • Page 193

    Troubleshooting Procedures: Power Amplifier Procedures 4-61 Table 4-20. Power Control DC Voltage Chart (Continued) RX MODE TX MODE LOCATION COMMENTS Loop Integrator Capacitor Control AMP Reference Q0500E 13.0 13.0 A+ - CR0500 Drop Q0501C 12.3 12.3 VQ0500E - B/E Drop Q0501E V pin 23 - B/E Drop Q0503E...

  • Page 194

    4-62 Troubleshooting Procedures: Power Amplifier Procedures 3. Power Intermittently Low (or Zero) and Current Less than 1 A. When Power Drops - Check LLA stage. 4. Power Zero and Current Greater Than 2 A. - Check harmonic filter, antenna switch, matching circuits between driver and final stages, and matching circuits beyond final stage.

  • Page 195

    When replacing either the driver or final device, apply thermal compound on the heatsink surface. Torque the screws to the correct value; see the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20).

  • Page 196

    4.5.2.2.5 Power Control and Protection Circuitry 1. Localizing Problems to a Circuit Power leveling and current limiting are set to values detailed in the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20). These values will vary from unit to unit, depending on the unique variations of each unit. If symptoms indicate that either of these circuits have failed, verify that the radio has been properly aligned before investigating the circuitry.

  • Page 197

    P0853, pin 9, should measure approximately 1.3 V. NOTE: If any part of the power leveling circuitry is replaced, perform the power set procedure. See the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20) for details.

  • Page 198: Watt And 35 Watt Power Amplifiers, Mhz Band, General Troubleshooting And Repair Notes

    ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20). NOTE: Due to the high frequency of operation, it is imperative that you use specified Motorola parts when component replacement is necessary. At these frequencies, second and third order properties of the components are very important and are part of the circuit's design.

  • Page 199

    Troubleshooting Procedures: Power Amplifier Procedures 4-67 4.5.3.1.2 PA Functional Testing To test the PA assembly for proper operation, perform the following steps: NOTE: The following instructions pertain to both the 15 Watt and 35 Watt power amplifiers. A distinction between the two PA’s is given only where necessary. 1.

  • Page 200

    4-68 Troubleshooting Procedures: Power Amplifier Procedures Table 4-23. DC Voltages and Input Power Chart CONTROL POWER IN Test Keyed 9.4 V 9.6 V VOLTAGE A+ .V (mW) DRIVE Transmit See note 13.0 Receive 13.0 a. Set initially to zero. Increase value until power equals 17 wafts(15-Watt radio) or 38 Watts (35-Watt radio) or 11.0 V maximum.

  • Page 201

    Troubleshooting Procedures: Power Amplifier Procedures 4-69 Table 4-24. Power Control DC Voltage Chart (Continued) RX MODE TX MODE LOCATION COMMENTS U0500 Ground Control AMP Input Control AMP Input (not used) Control Voltage Limit (cutback at 3.3 V) N.C. Power Set from D-A (max power at 1.5 V) Power Set Buffer Out Coupler Buffer Out Forward Detect Voltage...

  • Page 202

    4-70 Troubleshooting Procedures: Power Amplifier Procedures Table 4-24. Power Control DC Voltage Chart (Continued) RX MODE TX MODE LOCATION COMMENTS — — — — — — 9.6-V Programming (N.C.) — — — — — — 9.6-V Programming (N.C.) Ground 10.8 13.6 16.5 10.0...

  • Page 203

    Troubleshooting Procedures: Power Amplifier Procedures 4-71 Table 4-25. Antenna Switch DC Voltage Chart TYPICAL TX LOCATION TYPICAL RX NO PRE- COMMENTS DRIVE CR9920 ANODE TX Series P.I.N. diode CATHODE (on in TX mode) CR9921 ANODE TX Shunt P.I.N. diode CATHODE —...

  • Page 204

    NOTE: When replacing the module, apply thermal compound on the heatsink surface. Torque the screws to the correct value; see the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20). July 1, 2002...

  • Page 205

    Troubleshooting Procedures: Power Amplifier Procedures 4-73 When testing is complete, replace any capacitors or resistors that were removed for testing with new parts. 3. Testing the Final Stage (35-Watt Models Only) The final stage is capable of producing over 50 Watts. Be sure to protect power measuring equipment with series attenuation.

  • Page 206

    Power leveling and current limiting (35-Watt models only) are set to values detailed in the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20). These values will vary from unit to unit, depending on the unique variations of each unit.

  • Page 207

    Table 4-24 for typical values. NOTE: If any part of the power leveling circuitry is replaced, perform the power set procedure. See the ASTRO Digital Spectra and Digital Spectra Plus Mobile Radios Basic Service Manual (68P81076C20) for details. 68P81076C25-C July 1, 2002...

  • Page 208

    4-76 Troubleshooting Procedures: Power Amplifier Procedures This Page Intentionally Left Blank July 1, 2002 68P81076C25-C...

  • Page 209: Chapter 5 Troubleshooting Charts, Introduction, List Of Troubleshooting Charts

    Chapter 5 Troubleshooting Charts Introduction This chapter contains detailed troubleshooting flowcharts. These charts should be used as a guide in determining the problem areas. They are not a substitute for knowledge of circuit operation and astute troubleshooting techniques. It is advisable to refer to the related detailed circuit descriptions in the theory section prior to troubleshooting a radio.

  • Page 210

    Troubleshooting Charts: List of Troubleshooting Charts Table 5-1. List of Troubleshooting Charts (Continued) Chart Page Description Number Number 5-14 Chart C.19 No RX Audio 5-15 Chart C.20 No TX Modulation 5-16 Chart C.21 Key Load Fail 5-17 Chart C.22 800 MHz Receiver Front-End Hybrid 5-17 Chart C.23 UHF Receiver Front-End Hybrid...

  • Page 211: Rf Board Back-end

    Troubleshooting Charts Bad SINAD. Bad 20Db Quieting. No Recovered Audio. Note: Inject Modulated On Carrier Frequency Signal As Required. Inject 1 st IF into Johnson connector on RF board IF Freqs: 109.65MHz Check RX Audio Front End. Heard? Check 2nd VCO "Second VCO Checks"...

  • Page 212

    Troubleshooting Charts Note 1: See Control Head Troubleshooting Chart In Spectra Detailed Service Manual. Control Head Display: "FAIL 01/82" Note 2: See VOCON Board Troubleshooting Chart. "FAIL 01/84" Control Head Display: "FAIL 01/90" or Blank "FAIL 01/88" START "FAIL 01/02" START Replace and/or Check Busy In...

  • Page 213: Radio Power-up Fail

    Troubleshooting Charts Radio Power-Up Synopsis Failure. This failure assumes the radio fails to power up correctly and Verify Host Port: does not send any Power up Use ohmmeter to Verify standard failure messages via the electrically verify bias per table display or serial bus.

  • Page 214: Bootstrap Fail

    Troubleshooting Charts Host C Synopsis Bootstrap Failure. The host C bootstrap mode is used during reprogramming of the host C and DSP FLASH ROMs. Refer to appropriate Verify standard Theory of Operation section for bias per table description of bootstrap Table 3.

  • Page 215: General Hardware Failure, Host Rom Checksum Failure

    Troubleshooting Charts Fail 01/81 Host ROM Checksum Synopsis Failure This failure indicates the Host ROM program code is incorrect. It is implied that the host Visually inspect all processor found and executed leads to U205 and enough valid code at power up U210 with a 5x glass.

  • Page 216: Or 002, External Eeprom Checksum Failure, Slic Initialization Failure

    Troubleshooting Charts Fail 01/82 or 002 External EEPROM Fail 01/84 Synopsis Synopsis Checksum Failure SLIC Init Failure This failure indicates the This failure indicates a failure External EEPROM data in verification of the data in the containing mostly customer SLIC parallel programming Use ohmmeter to electrically specific channel/mode Verify standard...

  • Page 217: Mcu (host Mc) External Sram Failure, Internal Eeprom Checksum Failure

    Troubleshooting Charts Fail 01/88 Host C External RAM Synopsis Failure. This failure indicates a failure in the C external SRAM at power up test. Some basic Verify standard failure modes: bias per table 1) Missing supply or ground to Fail 01/92 Table 3 pertaining SLIC.

  • Page 218: A0, Adsic Checksum Failure, Dsp Rom Checksum Failure

    5-10 Troubleshooting Charts Fail 02/81 Fail 02/A0 Synopsis DSP ROM Checksum ADSIC Checksum Synopsis The ADSIC calculates a checksum of the Failure Failure This failure indicates the DSP configuration bus data programmed ROM program code is incorrect. through the Host C SPI interface. This It is implied that the DSP found failure indicates some problem with the Visually inspect all...

  • Page 219: Dsp External Sram Failure U414, Dsp External Sram Failure U403

    Troubleshooting Charts 5-11 Fail 02/84 Synopsis Fail 02/88 Synopsis DSP SRAM U403 On power-up the DSP writes DSP SRAM U414 Failure On power-up the DSP writes data to the device and then Failure data to the device and then verifies the data. This failure verifies the data.

  • Page 220: Dsp External Sram Failure U402, General Dsp Hardware Failure

    5-12 Troubleshooting Charts Fail 02/90 Fail 02/82 DSP Hardware Synopsis Failure Synopsis On power-up the host C sends DSP SRAM U402 several handshake commands On power up the DSP writes Failure through the host interface to the DSP system to coordinate data to the device and then Verify standard the power up programming of...

  • Page 221: Secure Hardware Failure

    Troubleshooting Charts 5-13 Fail 09/10 Synopsis Secure Hardware This failure relates only to Failure secure equipped radios and Fail 09/90 Synopsis indicates a power up self-test Secure Hardware This failure relates only to failure for the secure module. Failure secure equipped radios and Verify connections More specifically this failure indicates a power up self-test...

  • Page 222

    5-14 Troubleshooting Charts No Receive Audio Verify signals per Verify signal Fig. W2 at points at output of indicated. U524 pin 2. Set radio to test mode CSQ. Inject a 1KHz modulated signal at the carrier. Frequency at -60dBm level Verify signal with 3KHz deviation.

  • Page 223: No Tx Modulation

    Troubleshooting Charts 5-15 No Tx Modulation Verify 1KHz signal present at U401. Verify standard bias per Table 6. Verify control Fig. W8 signals at U524. Trace 4 Ext Mic present? VRX TX audio Low Check for continuity Signal between U406 present? Isolate and Standard...

  • Page 224: Key Load Fail

    Keyload mode. NTN1562 NTN8408 T3011DX DES-OFB 2) Use of wrong KVL or KVL NTN1563 NTN8409 T3011DX DES-OFB & DES cable for ASTRO Digital Spectra NTN1564 NTN8410 T3011DX DES-OFB & DES-XL radio. NTN1565 NTN8411 T3011DX & T3014DX DES-OFB & DVP-XL 3) Failure of secure module.

  • Page 225: Mhz Receiver Front-end Hybrid, Uhf Receiver Front-end Hybrid

    Troubleshooting Charts 5-17 START START Check Module Gain: Inject Check Module Gain: Inject Measure Transceiver On-Channel Signal Measure Transceiver Signal -20dBm at J9127 Sinad by Injecting Sinad by Injecting (851-870 MHz) of -20dBm Measure at IF Output Pad Signal at J9127 at J9127: Measure Level 109.65 Signal at J9127...

  • Page 226: Vhf Receiver Front-end Hybrid

    5-18 Troubleshooting Charts START Check Module Gain: Inject Measure Transceiver 160MHz -20dBm at J9127 Sinad by Injecting Measure at IF Output Signal at J9127 Sinad No Problem with Recheck RF Board and >-13 with <-120 with Preamp Preamp; >-22 Non- RX Front End or Transceiver Sinad <-117 non-...

  • Page 227: Astro Spectra Plus Vocon Power-up Failure

    Troubleshooting Charts 5-19 Verify Standard Bias per Table (xref to standard operating bias table) See Chart C.26 Standard Bias Measure waveform at R428, should match Figure 6-11 Make sure the following Refer board to components are placed Fixed? Replace U408 Fixed? Replace Y401 Service Depot...

  • Page 228: Astro Spectra Plus Vocon Dc Supply Failure

    5-20 Troubleshooting Charts Check for 1.8V at R419 Make sure the following Refer board to components are placed Fixed? Replace U410 Service Depot and soldered correctly: Present? U410, C430 R431, R451, R452, C433, C415, R419 Repair proper Check for 3.0 V at R420 components Make sure the following components are placed...

  • Page 229: Astro Spectra Plus Vocon Tx Modulation Failure Sheet 1 Of 4

    Troubleshooting Charts 5-21 Inspect and Repair Repair proper components U202 Inject a 1kHz tone into MIC with sufficient amplitude to produce 3kHz of deviation, PTT radio Make sure the following components Replace U202 Check 5V supply of U202-8 are placed and soldered correctly: and GND U202-4 U202, R207, R208, C216, R209, R226, Measure waveform at...

  • Page 230: Astro Spectra Plus Vocon Tx Modulation Failure Sheet 2 Of 4

    5-22 Troubleshooting Charts Inspect U201 Repair component Check Patriot clocks C326 - T1 - 16.8MHz R428 - T2 - 32kHz 16.8MHz Measure waveform at U201-39 Repair regulator Repair components Clock should match Figure 6-12 circuit Inspect and repair Patriot IC - U300 Inspect R200, Waveform Repair oscillator...

  • Page 231: Astro Spectra Plus Vocon Tx Modulation Failure Sheet 3 Of 4

    Troubleshooting Charts 5-23 Inspect U402, also check 3V at pin6 and GND at pin 15 Inspect U501 Repair U402 Repair U501 Inspect U404, also check 5V at pin8 and GND at pin 4 Is problem with TXPA_EN Check for GND Keyed9.4_EN or at J501-14 Present?

  • Page 232: Astro Spectra Plus Vocon Tx Modulation Failure Sheet 4 Of 4

    5-24 Troubleshooting Charts Put the radio into Test mode (CSQ 1). Connect RF Signal Generator to the RF input of the radio. Use Dev=3kHz, Amplitude=-47dBm and Freq=851.025MHz Amplitude of Measure waveform at TP403, Measure waveform at the Vocon should match Figure 6-17 waveform Connector, J501 pin 40.

  • Page 233: Astro Spectra Plus Vocon Secure Hardware Failure

    Troubleshooting Charts 5-25 Make sure the Secure Module is connected to the Plus VOCON board and the radio is ON Measure the voltage at pins 1, 2 and 20 on the secure connector. The voltage reading should be between 10V and 13V Measure voltage on Q600, Voltages Verify placement, soldering...

  • Page 234: Astro Spectra Plus Vocon Key Load Fail

    5-26 Troubleshooting Charts Make sure the Secure Module is connected Synopsis to the Plus VOCON board and the radio is ON This failure relates only to secure equipped radios and indicates a failure to load a key with the KVL indicated by the message “xFail”...

  • Page 235: Chapter 6 Troubleshooting Waveforms, Introduction, Astro Spectra Waveforms, Waveform W1: Power-on Reset Timing

    Chapter 6 Troubleshooting Waveforms Introduction This chapter contains images of waveforms that might be useful in verifying operation of certain parts of the circuitry. These waveforms are for reference only; the actual data depicted will vary depending upon the operating conditions. ASTRO Spectra Waveforms Waveform W1: Power-On Reset Timing SWB+...

  • Page 236: Waveform W2: Dsp Ssi Port Rx Mode, Waveform W3: Dsp Ssi Port Tx Mode Csq

    Troubleshooting Waveforms: ASTRO Spectra Waveforms Waveform W2: DSP SSI Port RX Mode 2893 Acquisitions Tek stopped: Ch1 Freq 19.991kHz Low signal amplitude 5.00V M 20.0us Ch1 2.2 V 5.00V 5.00V MAEPF-24377-O W2: DSP SSI Port RX mode. Receiving 1KHz tone @ 3KHz deviation, -60dBm. Trace 1 - RFS Trace 2 - RXD Trace 3 - SCKR (2.4/0.600MHz)

  • Page 237: Waveform W4: Abacus Programming At Mode Change, Waveform W5: Abacus/adsic Interface

    Troubleshooting Waveforms: ASTRO Spectra Waveforms Waveform W4: ABACUS Programming at Mode Change 13 Acquisitions Tek stopped: Ch1 Freq 74.610kHz 2.00V M 10.0us Ch1 2.2 V MAEPF-24379-O W4: ABACUS programming captured during mode change. Trace 1 - (ADSIC) SBI Waveform W5: ABACUS/ADSIC Interface Tek stopped: 34513 Acquisitions Ch1 Freq...

  • Page 238: Waveform W6: Spi Bus Programming Adsic, Waveform W7: Receive Audio

    Troubleshooting Waveforms: ASTRO Spectra Waveforms Waveform W6: SPI Bus Programming ADSIC 18 Acquisitions Tek stopped: Tek stopped: Ch1 Freq = Hz No period found 5.00V 5.00V M 50ns Ch1 2.2 V 5.00V W6: SPI Bus Programming ADSIC. MAEPF-24381-O Trace 1 - ADSIC_SEL* Trace 2 - SPI_SCK Trace 3 - MOSI Note: These waveforms are typical to...

  • Page 239: Waveform W8: Transmit Audio, Waveform W9: Power-down Reset

    Troubleshooting Waveforms: ASTRO Spectra Waveforms Waveform W8: Transmit Audio Tek stopped: 507 Acquisitions Ch1 Freq 7.9872kHz Low signal amplitude 5.00V 500mV M 200us Ch1 1.5 V 300mV 100mV W8: Transmit Audio. 1KHz Tone which provides 3KHz deviation. Trace 1 - IRQB @ DSP (8KHz) Trace 2 - MODIN Trace 3 - MIC @ node P502/R415 Trace 4 - MAI @ U406...

  • Page 240: Waveform W10: Adsic 2.4 Mhz Reference

    Troubleshooting Waveforms: ASTRO Spectra Waveforms Waveform W10: ADSIC 2.4 MHz Reference 493 Acquisitions Tek stopped: Ch1 Freq 2.4038MHz 2.00V M 200ns 1.64 V W10 ADSIC 2.4 MHz Reference Trace 1 - IDC @ U406 MAEPF-24385-O July 1, 2002 68P81076C25-C...

  • Page 241: Astro Spectra Digital Plus Vocon Board Waveforms, Khz Clock Waveform

    Troubleshooting Waveforms: ASTRO Spectra Digital Plus VOCON Board Waveforms ASTRO Spectra Digital Plus VOCON Board Waveforms This section contains images of waveforms specific to the ASTRO Spectra Digital Plus VOCON board. These waveforms might be useful in verifying operation of certain parts of the circuitry. These waveforms are for reference only;...

  • Page 242: Mhz Clock Waveform, Tx Modulation Out Waveform

    Troubleshooting Waveforms: ASTRO Spectra Digital Plus VOCON Board Waveforms 16.8 MHz Clock Waveform Trace 1 — TP401 — 16.8 MHz Clock TX Modulation Out Waveform Transmitting 1 kHz tone at 85mVrms into microphone Trace 1 — U201 — 9 July 1, 2002 68P81076C25-C...

  • Page 243: Differential Addag Output Waveform, Tx Ssi Waveform

    Troubleshooting Waveforms: ASTRO Spectra Digital Plus VOCON Board Waveforms Differential ADDAG Output Waveform Transmitting 1 kHz tone at 85mVrms into microphone Trace 1 — U201 — 4 Trace 2 — U201 — 5 TX SSI Waveform Transmitting 1 kHz tone at 85mVrms into microphone Trace 1 —...

  • Page 244: Spi Bus Waveform, Tx 1 Khz Tone Waveform

    6-10 Troubleshooting Waveforms: ASTRO Spectra Digital Plus VOCON Board Waveforms SPI Bus Waveform Radio Power Up Trace 1 — U201 — 41 - Data Trace 2 — U201 — 43 - Chip Select Trace 3 — U201 — 42 - Clock TX 1 kHz Tone Waveform Transmitting 1 kHz tone at 85mVrms into microphone...

  • Page 245: Serial Audio Port Waveform, Rx Audio Waveform

    Troubleshooting Waveforms: ASTRO Spectra Digital Plus VOCON Board Waveforms 6-11 Serial Audio Port Waveform Transmitting 1 kHz tone at 85mVrms into microphone Trace 1 — U402 — 7 - Frame Sync Trace 2 — U402 — 11 - Clock Trace 3 — U402 — 13 - Data RX Audio Waveform Receiving 1 kHz tone at 3 kHz Dev, -47dBm...

  • Page 246: Rx Bbp Waveform, Secure Interface Waveform

    6-12 Troubleshooting Waveforms: ASTRO Spectra Digital Plus VOCON Board Waveforms RX BBP Waveform Receiving 1 kHz tone at 3 kHz Dev, -47dBm Trace 1 — TP221 — Frame Sync Trace 2 — TP223 — Data Trace 3 — TP219 — Clock Secure Interface Waveform Receiving 1 kHz tone at 3 kHz Dev, -47dBm Secure Mode...

  • Page 247: Khz Frame Sync For Security Circuitry Waveform

    Troubleshooting Waveforms: ASTRO Spectra Digital Plus VOCON Board Waveforms 6-13 8 kHz Frame Sync for Security Circuitry Waveform Receiving 1 kHz tone at 3 kHz Dev, -47dBm Secure Mode Trace 1 — U601 — 5 68P81076C25-C July 1, 2002...

  • Page 248

    6-14 Troubleshooting Waveforms: ASTRO Spectra Digital Plus VOCON Board Waveforms This Page Intentionally Left Blank July 1, 2002 68P81076C25-C...

This manual also for:

Digital spectra plus

Comments to this Manuals

Symbols: 0
Latest comments: