Motorola HT Series Service Manual
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Motorola HT Series Service Manual

Motorola HT Series Service Manual

Professional series two-way portable radios
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Troubleshooting

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Summary of Contents for Motorola HT Series

  • Page 1 ™ HT Series ™ MTX Series ™ PRO Series Professional Series Two-Way Portable Radios Detailed Service Manual...
  • Page 3 Document History The following major changes have been implemented in this manual since the previous edition: Edition Description Date 6881088E46-E The Theory of Operation section has been divided into July, 2005 the following six sections: Distribution Keypad UHF Band 1 UHF Band 2 Lowband, 800 MHz, PassPort, and 900 MHz Troubleshooting Flow Charts in the Maintenance sec-...
  • Page 5 ™ HT Series Title Page ™ MTX Series ™ PRO Series Professional Series Two-Way Portable Radio Detailed Service Manual Motorola, Inc. 8000 West Sunrise Boulevard 6881088C46-F Fort Lauderdale, Florida 33322...

  • Page 6: Foreword

    No duplication or distribution of this document or any portion thereof shall take place without the express written permission of Motorola. No part of this manual may be reproduced, distributed, or transmitted in any form or by any means, electronic or mechanical, for any purpose without the express written permission of Motorola.

  • Page 7: Table Of Contents

    Table of Contents Table of Contents Foreword ....................... ii Product Safety and RF Exposure Compliance................ii Manual Revisions ........................ii Computer Software Copyrights ....................ii Document Copyrights.........................ii Disclaimer...........................ii Trademarks ..........................ii List of Figures ..................... xi Intrinsically Safe Radio Information ............xix FMRC Approved Equipment ....................xix Repair of FMRC Approved Products..................xx Repair ..........................xx Relabeling ........................xx...
  • Page 8 Table of Contents Chapter 4 UHF Band 1 Theory of Operation ........4-1 Transmitter........................4-1 4.1.1 General ......................4-1 4.1.2 Power Amplifier....................4-1 4.1.3 Antenna Switch....................4-2 4.1.4 Harmonic Filter ....................4-2 4.1.5 Antenna Matching Network................4-2 4.1.6 Power Control Integrated Circuit (PCIC)............4-2 Receiver........................
  • Page 9 Table of Contents 6.3.3 Automatic Gain Control Circuit................. 6-7 Frequency Generation Circuitry ..................6-8 Synthesizer ........................6-9 Voltage-Controlled Oscillator (VCO) ................6-10 Chapter 7 Low Band, 800 MHz, PassPort & 900 MHz Theory of Operation............7-1 Introduction ........................7-1 Low Band Transmitter....................7-1 7.2.1 Power Amplifier (PA)..................
  • Page 10 Table of Contents 7.9.4.2 Microcontroller (MCU) ................7-15 7.9.4.3 Low Speed Data Filter................7-15 7.9.4.4 Keyboard Circuit................... 7-15 7.9.4.5 BackLight Driver and LED's..............7-16 7.9.4.6 Voice Storage..................7-16 7.10 900 MHz Transmitter ....................7-16 7.10.1 Power Amplifier....................7-17 7.10.2 Antenna Switch....................7-17 7.10.3 Harmonic Filter ....................
  • Page 11 Table of Contents 8.10.9 Troubleshooting Flow Chart for VCO............. 8-17 8.11 UHF Band 2 Troubleshooting Charts................8-18 8.11.1 Troubleshooting Flow Chart for Controller for all models except those with PCB 8486686Z02.............. 8-18 8.11.2 Troubleshooting Flow Chart for Controller for models with PCB 8486686Z02 ..................
  • Page 12 viii Table of Contents 8.15 PassPort Trunking Troubleshooting Chart..............8-48 8.16 Keypad Troubleshooting Chart ................... 8-49 8.17 900 MHz Troubleshooting Charts ................8-50 8.17.1 Troubleshooting Flow Chart for Controller (Sheet 1 of 2) ......8-50 8.17.2 Troubleshooting Flow Chart for Controller (Sheet 2 of 2) ......8-51 8.17.3 Troubleshooting Flow Chart for Receiver (Sheet 1 of 2) .......
  • Page 13 9.29 900 MHz Circuit Board/Schematic Diagrams and Parts List (PCB 8485910Z01)..9-375 Appendix A Replacement Parts Ordering..........A-1 Basic Ordering Information ...................A-1 Transceiver Board and VOCON Board Ordering Information........A-1 Motorola Online......................A-1 Mail Orders ........................A-1 Telephone Orders ......................A-2 Fax Orders ........................A-2 Parts Identification ......................A-2...
  • Page 14 Table of Contents...

  • Page 15: List Of Figures

    List of Figures List of Figures Figure 2-1. DC Power Distribution Block Diagram ..............2-1 Figure 3-1. Keypad Block Diagram ..................... 3-1 Figure 3-2. Controller Block Diagram ..................3-2 Figure 3-3. RTC Circuit ....................... 3-3 Figure 4-1. Transmitter Block Diagram ..................4-1 Figure 4-2.
  • Page 16 List of Figures Figure 9-13. VHF/UHF Controller Microprocessor Schematic Diagram........9-17 Figure 9-14. Controller Memory Schematic Diagram..............9-18 Figure 9-15. Controller Audio Power Amplifier Schematic Diagram ......... 9-19 Figure 9-16. Controller Interface Schematic Diagram............... 9-20 Figure 9-17. UHF (403-470 MHz) 5000/7000 Series Main Board Top Side PCB 8480450Z03........................
  • Page 17 List of Figures xiii Figure 9-55. UHF (403-470 MHz) Synthesizer Schematic Diagram ......... 9-72 Figure 9-56. UHF (403-470 MHz) Voltage Controlled Oscillator Schematic Diagram....9-73 Figure 9-57. UHF (403-470 MHz) Harmonic Filter Schematic Diagram........9-74 Figure 9-58. UHF (403-470 MHz) Transmitter Schematic Diagram .......... 9-75 Figure 9-59.

  • Page 18: Uhf Band

    List of Figures Figure 9-104. UHF (450-527 MHz) Voltage Controlled Oscillator Schematic Diagram ..9-141 Figure 9-105. UHF (450-527 MHz) Transmitter Schematic Diagram........9-142 Figure 9-106. UHF (450-527 MHz) 5000/7000 Series Main Board Top Side PCB 8485641Z06......................... 9-147 Figure 9-107. UHF (450-527 MHz) 5000/7000 Series Main Board Bottom Side PCB 8485641Z06.........................
  • Page 19 List of Figures Figure 9-147. UHF Band 2 Voltage Controlled Oscillator Schematic Diagram ....... 9-201 Figure 9-148. UHF Band 2 Harmonic Filter Schematic Diagram ..........9-202 Figure 9-149. UHF Band 2 Transmitter Schematic Diagram........... 9-203 Figure 9-150. Complete Controller Schematic Diagram............9-204 Figure 9-151.
  • Page 20 List of Figures Figure 9-190. VHF (136-174 MHz) Synthesizer Schematic Diagram ........9-262 Figure 9-191. VHF (136-174 MHz) Voltage Controlled Oscillator Schematic Diagram... 9-263 Figure 9-192. VHF (136-174 MHz) Transmitter Schematic Diagram ........9-264 Figure 9-193. VHF (136-174 MHz) 5000/7000 Series Main Board Top Side PCB No.
  • Page 21 List of Figures xvii Figure 9-238. Low Band (29.7-42/35-50 MHz) Main Board Top Side PCB......9-337 Figure 9-239. Low Band (29.7-42/35-50 MHz) Main Board Bottom Side PCB ....... 9-338 Figure 9-240. Low Band (30-50 MHz) Controls and Switches Diagram........9-339 Figure 9-241.
  • Page 22 xviii List of Figures...

  • Page 23: Intrinsically Safe Radio Information

    FM Approval labeling. Radios will not be “upgraded” or converted to Intrinsically safe, and or labeled in the field, after it has been shipped from the manufacturing location. Modifications can only be made by the original product manufacturer (Motorola) at one of its FM audited manufacturing facilities.

  • Page 24: Repair Of Fmrc Approved Products

    REPAIRS FOR MOTOROLA PRODUCTS WITH FMRC APPROVAL ARE THE RESPONSIBILITY OF THE USER. You should not repair or relabel any Motorola- manufactured communication equipment bearing the FMRC Approval label (“FMRC Approved Product”) unless you are familiar with the current FMRC Approval standard for repairs and service (“Class Number 3605”).

  • Page 25: Do Not Substitute Options Or Accessories

    Repair of FMRC Approved Products Do Not Substitute Options or Accessories The Motorola communications equipment certified by Factory Mutual is tested as a system and consists of the FM Approved portable, FM Approved battery, and FM Approved accessories or options, or both. This FM Approved portable and battery combination must be strictly observed.
  • Page 26 xxii Repair of FMRC Approved Products Notes...

  • Page 27: Chapter 1 Introduction

    1.2.1 Warranty Period The terms and conditions of warranty are defined fully in the Motorola dealer or distributor or reseller contract. These conditions may change from time to time and the following notes are for guidance purposes only. 1.2.2 Return Instructions In instances where the product is covered under a “return for replacement”...

  • Page 28: Related Documents

    Motorola. If the part number is appended with an asterisk, the part is serviceable by a Motorola depot only. If a parts list is not included, this generally means that no user-serviceable parts are available for that kit or assembly.

  • Page 29: Radio Model Chart And Specifications

    7:00 A.M. to 7:00 P.M. (Central Standard Time) Caribbean: Monday through Friday (Chicago, U.S.A.) 1-847-538-8023 To Order Parts in the United States of Motorola Parts America: (United States and Canada) 1-800-422-4210, or 847-538-8023 Customer Care and Services Division 1-800-826-1913, or 410-712-6200 (U.S. Federal...
  • Page 30 Introduction: Radio Model Information Table 1-2. Radio Model Number Example: AAH25KC9AA2 and LAH25KDC9AA3 Type Model Freq. Power Physical Channel Feature Model Model Protocol of Unit Series Band Level Packages Spacing Level Revision Package 2.5W No Display Program- Conven- 2F for AA (136-174 mable tional...

  • Page 31: Chapter 2 Radio Power Distribution

    Chapter 2 Radio Power Distribution A block diagram of the DC power distribution throughout the radio board is shown in Figure 2-1. A 7.5V battery supplies the basic radio power (UNSWB) directly to the electronic on/off control, audio power amplifier, 3.5V regulator, power amplifier automatic level control (ALC), and low battery detect circuit.
  • Page 32 Radio Power Distribution: Table 2-1. VDD Regulator Scheme by Band Band Regulator Scheme Dual Dual 800 MHz Dual 900 MHz Dual Table 2-2. Radio Jumpers Dual Vdd Single Vdd Jumpers Regulator Regulator Scheme Scheme R401 R402 R403 R404 R405 R = Regulator Jumper...

  • Page 33: Chapter 3 Keypad

    Chapter 3 Keypad The keypad block diagram is shown in Figure 3-1. The comparator compares the voltage when any one of the keypad row or keypad column keys is pressed. Pressing a key sends a message to the microprocessor through the output (KEY_INT) line signifying that a key has been pressed. The microprocessor then samples the analog to digital voltages at the keypad row and keypad column, then makes a comparison with a map table to identify the key pressed.

  • Page 34: Mcu Digital

    Keypad: Controller Board External Mod Out Microphone To Synthesizer Internal Microphone 16.8 / 17.0 MHz Reference Clock Audio/Signalling External from Synthesizer Speaker Recovered Audio Audio Power ASFIC Squelch Amplifier/Filter Internal 3.3V Speaker Regulator (Vdda) SCI to Side To RF Board Connector MCU Digital Microcontroller...

  • Page 35: Circuit Description

    Keypad: Controller Board 3.1.3 Circuit Description The RTC module circuit, shown in Figure 3-3, is powered by the MODB/VSTBY pin and PI6/PI7 from the crystal oscillator circuit. A clock frequency of 38.4 kHz from a crystal oscillator provides the reference signal which is divided down to 1 Hz in the processor. As the RTC module is powered separately from the processor Vdd, the RTC is kept active through the MODB/VSTBY pin which provides the lithium-ion battery back-up power when the radio is switched off.

  • Page 36: Audio/Signaling

    Keypad: Controller Board 3.1.5 Audio/Signaling The audio/signalling/filter/companding IC (ASFIC) and the audio power amplifier (Figure 3-2 on page 3-2) form the main components of the audio/signalling section of the controller board. Inputs include a 16.8 MHz clock from the synthesizer, recovered audio and squelch, MCU control signals, and external or internal microphones.

  • Page 37: Chapter 4 Uhf Band 1 Theory Of Operation

    UHF Band 1 Theory of Operation: Transmitter Chapter 4 UHF Band 1 Theory of Operation Transmitter P C I C Antenna Vcontrol Vcontrol Jack Antenna Switch/ From VCO PA - F i n a l Harmonic Filter/ Driver S t ag e Matching Network Figure 4-1.

  • Page 38: Antenna Switch

    UHF Band 1 Theory of Operation: Transmitter 4.1.3 Antenna Switch The antenna switch circuit consists of two PIN diodes (CR101 and CR102), a pi network (C107, L104 and C106), and two current limiting resistors (R101, R170). In the transmit mode, B+ at PCIC (U102) pin 23 will go low and turn on Q111 where a B+ bias is applied to the antenna switch circuit to bias the diodes “on”.

  • Page 39: Receiver

    UHF Band 1 Theory of Operation: Receiver Receiver Antenna Pin Diode Varactor Varactor Antenna Crystal RF Amp Mixer IF Amp Tuned Filter Tuned Filter Switch RF Jack Filter First LO from VCO Control Voltage from ASFIC U301 Demodulator Limiter Recovered Audio RSSI 455kHz 455kHz...

  • Page 40: Receiver Back-End

    UHF Band 1 Theory of Operation: Frequency Generation Circuitry The output of the post-RF amplifier filter which is connected to the passive double balanced mixer consists of T301, T302 and CR306. Matching of the filter to the mixer is provided by C381. After mixing with the first LO signal from the voltage controlled oscillator (VCO) using low side injection, the RF signal is down-converted to the 44.85 MHz IF signal.

  • Page 41: Synthesizer

    UHF Band 1 Theory of Operation: Synthesizer The Frequency Generation Circuitry is composed of two main ICs: • Fractional-N synthesizer (U201) • VCO/Buffer IC (U241) Designed in conjunction to maximize compatibility, the two ICs provide many of the functions that normally would require additional circuitry.

  • Page 42: Voltage-Controlled Oscillator (Vco)

    UHF Band 1 Theory of Operation: Voltage-Controlled Oscillator (VCO) The loop filter which consist of C231, C232, C233, R231, R232 and R233 provides the necessary dc steering voltage for the VCO and determines the amount of noise and spur passing through. In achieving fast locking for the synthesizer, an internal adapt charge pump provides higher current at pin 45 of U201 to put synthesizer within the lock range.
  • Page 43 UHF Band 1 Theory of Operation: Voltage-Controlled Oscillator (VCO) The VCOBIC (U241) in conjunction with the Fractional-N synthesizer (U201) generates RF in both the receive and the transmit modes of operation. The TRB line (U241 pin 19) determines which oscillator and buffer will be enabled. A sample of the RF signal from the enabled oscillator is routed from U241 pin 12, through a low pass filter, to the prescaler input (U201 pin 32).
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  • Page 45: Chapter 5 Uhf Band 2 Theory Of Operation

    UHF Band 2 Theory of Operation: Transmitter Chapter 5 UHF Band 2 Theory of Operation Transmitter P C I C Antenna Vcontrol Vcontrol Jack Antenna Switch/ From VCO PA-Final Harmonic Filter/ Driver Stage Matching Network Figure 5-1. Transmitter Block Diagram 5.1.1 General (Refer to...

  • Page 46: Antenna Switch

    UHF Band 2 Theory of Operation: Transmitter 5.1.3 Antenna Switch The antenna switch circuit consists of two PIN diodes (CR101 and CR102), a pi network (C107, L104 and C106), and two current limiting resistors (R101, R170). In the transmit mode, B+ at PCIC (U102) pin 23 will go low and turn on Q111 where a B+ bias is applied to the antenna switch circuit to bias the diodes "on."...

  • Page 47: Receiver

    UHF Band 2 Theory of Operation: Receiver Receiver Antenna Pin Diode Varactor Varactor Antenna Crystal RF Amp Mixer IF Amp Tuned Filter Tuned Filter Switch RF Jack Filter First LO from VCO Control Voltage from ASFIC U301 Limiter Demodulator Recovered Audio RSSI 455kHz 455kHz...

  • Page 48: Receiver Back-End

    UHF Band 2 Theory of Operation: Frequency Generation Circuitry The output of the post-RF amplifier filter which is connected to the passive double balanced mixer consists of T301, T302, and CR306. Matching of the filter to the mixer is provided by C381. After mixing with the first LO signal from the voltage controlled oscillator (VCO) using low side injection, the RF signal is down-converted to the 44.85 MHz IF signal.

  • Page 49: Synthesizer

    UHF Band 2 Theory of Operation: Synthesizer The Frequency Generation Circuitry is composed of two main ICs: • Fractional-N synthesizer (U201) • VCO/Buffer IC (U241) Designed in conjunction to maximize compatibility, the two ICs provide many of the functions that normally would require additional circuitry.

  • Page 50: Voltage-Controlled Oscillator (Vco)

    UHF Band 2 Theory of Operation: Voltage-Controlled Oscillator (VCO) The loop filter, which consists of C231, C232, C233, R231, R232, and R233, provides the necessary DC steering voltage for the VCO and determines the amount of noise and spur passing through. In achieving fast locking for the synthesizer, an internal adapt charge pump provides higher current at pin 45 of U201 to put the synthesizer within the lock range.
  • Page 51 UHF Band 2 Theory of Operation: Voltage-Controlled Oscillator (VCO) The VCOBIC (U241), in conjunction with the Fractional-N synthesizer (U201), generates RF in both the receive and the transmit modes of operation. The TRB line (U241 pin 19) determines which oscillator and buffer will be enabled. A sample of the RF signal from the enabled oscillator is routed from U241 pin 12, through a low pass filter, to the prescaler input (U201 pin 32).
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  • Page 53: Chapter 6 Vhf Theory Of Operation

    Chapter 6 VHF Theory of Operation Transmitter P C I C Antenna Vcontrol Vcontrol Jack Antenna Switch/ From VCO Harmonic Filter/ Driver Final Stage Matching Network Figure 6-1. Transmitter Block Diagram 6.1.1 General (Refer to Figure 6-1.) The VHF transmitter contains five basic circuits: •...

  • Page 54: Antenna Switch

    VHF Theory of Operation: Transmitter 6.1.3 Antenna Switch The antenna switch circuit consists of two PIN diodes (D3521 and D3551), a pi network (C3531, L3551 and C3550), and three current limiting resistors (R3571, R3572, R3573). In the transmit mode, B+ at PCIC (U3502) pin 23 will go low and turn on Q3561 where a B+ bias is applied to the antenna switch circuit to bias the diodes “on.”...

  • Page 55: Receiver (For All Models Except Those With Pcb 8486473Z04)

    VHF Theory of Operation: Receiver (for all models except those with PCB 8486473Z04) Receiver (for all models except those with PCB 8486473Z04) Antenna Pin Diode Varactor Varactor Antenna Crystal RF Amp Mixer IF Amp Tuned Filter Tuned Filter Switch RF Jack Filter First LO Control Voltage...

  • Page 56: Receiver Back-End

    VHF Theory of Operation: Receiver (for all models except those with PCB 8486473Z04) The output of the post-RF amplifier filter is connected to the passive double balanced mixer which consists of T3301, T3302 and CR3301. Matching of the filter to the mixer is provided by C3317, C3318 and L3308.

  • Page 57: Receiver (For Models With Pcb 8486473Z04)

    VHF Theory of Operation: Receiver (for models with PCB 8486473Z04) Radio signal strength indicator, RSSI, a voltage signal, is used to drive Q3301 to saturation i.e. turned on. RSSI is produced by U3220 and is proportional to the gain of the RF amplifier and the input power to the radio.

  • Page 58: Receiver Front-End

    VHF Theory of Operation: Receiver (for models with PCB 8486473Z04) 6.3.1 Receiver Front-End (Refer to VHF Receiver Front-End Schematic Diagram on page 9-92, VHF Receiver Back-End Schematic Diagram on page 9-93, and VHF Transmitter Schematic Diagram on page 9-96.) The RF signal is received by the antenna and applied to a low-pass filter. For VHF, the filter consists of L3531, L3532, C3532 to C3563.

  • Page 59: Automatic Gain Control Circuit

    VHF Theory of Operation: Receiver (for models with PCB 8486473Z04) The IF IC (U3220) contains a quadrature detector using a ceramic phase-shift element (Y3202) to provide audio detection. Internal amplification provides an audio output level around 120mVrms (@60% deviation) from pin 8 of U3220. This demodulated audio is fed to the ASFIC_CMP IC (U404) in the controller section.

  • Page 60: Frequency Generation Circuitry

    VHF Theory of Operation: Frequency Generation Circuitry Frequency Generation Circuitry Voltage Multiplier Rx Out Mixer VCOBIC Aux3 Rx VCO Circuit Vmult1 U3801 Synthesizer Vmult2 U3701 Loop Filter Tx Out PA Driver 16.8 MHz Ref. Osc. Tx VCO Circuit MOD Out Modulating Signal Figure 6-4.

  • Page 61: Synthesizer

    VHF Theory of Operation: Synthesizer Synthesizer (Refer to the VHF Synthesizer Schematic Diagram on page 9-94.) The Fractional-N Synthesizer uses a 16.8MHz crystal (Y3761) to provide a reference for the system. The LVFractN IC (U3701) further divides this to 2.1MHz, 2.225 MHz, and 2.4 MHz as reference frequencies.

  • Page 62: Voltage-Controlled Oscillator (Vco)

    6-10 VHF Theory of Operation: Voltage-Controlled Oscillator (VCO) Voltage-Controlled Oscillator (VCO) (Refer to the VHF Voltage-Controlled Oscillator Schematic Diagram on page 9-95.) AUX3 (U3701 Pin2) U3701 Pin 32 Prescaler Out TRB_IN Pin 20 Pin 19 Pin 12 Pin7 Rx-SW TX/RX/BS Pin13 Tx-SW Switching Network...
  • Page 63 VHF Theory of Operation: Voltage-Controlled Oscillator (VCO) 6-11 The RF section of the VCOBIC(U3801) is operated at 4.54 V (VSF), while the control section of the VCOBIC and Fractional-N synthesizer (U3701) is operated at 3.3 V. The operation logic is shown in Table 6-1.
  • Page 64 6-12 VHF Theory of Operation: Voltage-Controlled Oscillator (VCO)

  • Page 65: Chapter 7 Low Band, 800 Mhz, Passport & 900 Mhz Theory Of Operation

    Chapter 7 Low Band, 800 MHz, PassPort & 900 MHz Theory of Operation Introduction This chapter provides a detailed theory of operation for the radio components. Schematic diagrams for the circuits described in the following paragraphs are located in Figures 9-238 through 9-284.

  • Page 66: Antenna Switch

    Low Band, 800 MHz, PassPort & 900 MHz Theory of Operation: Low Band Transmitter The LDMOS PA is capable of supplying an output power of 8W with an input signal of 0.3 W. The current drain is typically 2000 mA while operating in the frequency range of 29.7 - 50 MHz. The final stage gate is bias by a voltage from PCIC, pin 24.

  • Page 67: Low Band Receiver

    Low Band, 800 MHz, PassPort & 900 MHz Theory of Operation: Low Band Receiver Low Band Receiver The low band receiver consists of a front end, back end, and automatic gain control circuits. A block diagram of the receiver is shown in Figure 7-2.

  • Page 68: Receiver Back-End

    Low Band, 800 MHz, PassPort & 900 MHz Theory of Operation: Low Band Receiver 7.3.2 Receiver Back-End The output of crystal filter FL301 is connected to the input of IF amplifier transistor U301. Components L303 and C348 and R301 form the termination for the crystal filter and the signal is coupled to one gate of U301 by C303.

  • Page 69: Synthesizer

    Low Band, 800 MHz, PassPort & 900 MHz Theory of Operation: Synthesizer The synthesizer is powered by regulated 5V and 3.3 V. The 5 volt signal to the synthesizer as well as the rest of the radio is provided by U204. The 3.3 V signal is provided by U200 in the controller. The 5V signal goes to pins 13 and 30 while the 3.3 V signal goes to pins 5, 20, 34 and 36 of U201.

  • Page 70: Voltage Control Oscillators (Vco)

    Low Band, 800 MHz, PassPort & 900 MHz Theory of Operation: Voltage Control Oscillators (VCO) Both the normal and adapt charge pumps get their supply from the capacitive voltage multiplier made up of C247, C283, C284, C285, C286, and triple diodes D210 and D211. This circuit provides 13.3V at U205, pin 47.

  • Page 71: Diplexer/Output Filters

    Low Band, 800 MHz, PassPort & 900 MHz Theory of Operation: 800 MHz Transmitter 7.5.4 Diplexer/Output Filters The output of the buffer drives a pair of parallel filters forming a diplexer. One filter is a lowpass filter in the TX pass that passes 29.7 - 50 MHz signals for the transmitter into the power amplifier while rejecting the receive LO injection signals at 139 - 160 MHz.

  • Page 72: Antenna Switch

    Low Band, 800 MHz, PassPort & 900 MHz Theory of Operation: 800 MHz Transmitter This RF driver IC is capable of supplying an output power of 0.3 W (pin 13 and 14) with an input signal of 2.5 mW (4 dBm) (pin16). The current drain would typically be 200 mA while operating in the frequency range of 806-870 MHz.

  • Page 73: 800 Mhz Receiver

    Low Band, 800 MHz, PassPort & 900 MHz Theory of Operation: 800 MHz Receiver 800 MHz Receiver The receiver functions are shown in Figure 7-6 and are described in the paragraphs that follow. Antenna Pin Diode 3-Pole 3-Pole Antenna Ceramic Ceramic Crystal RFJack...

  • Page 74: Receiver Back-End

    7-10 Low Band, 800 MHz, PassPort & 900 MHz Theory of Operation: 800 MHz Receiver 7.7.2 Receiver Back-End The output of crystal filter FL350 is matched to the input of the dual gate MOSFET IF amplifier transistor U352 by components L355, R359 and C376. Voltage supply to the IF amplifier is taken from the receive 5 volts (R5).

  • Page 75: Frequency Generation Circuit

    Low Band, 800 MHz, PassPort & 900 MHz Theory of Operation: 800 MHz Receiver 7-11 • The RF level at which the front end AGC is activated, and • The slope of the voltage at the output of U302 vs. the strength of the incoming RF at the antenna. As the RF into the antenna increases the following occurs: •...

  • Page 76: Synthesizer

    7-12 Low Band, 800 MHz, PassPort & 900 MHz Theory of Operation: Synthesizer Transmit modulation from the ASFIC is supplied to pin10 of U201. Internally the audio is digitized by the Low Voltage Fractional-N synthesizer and applied to the loop divider to provide the low-port modulation.

  • Page 77: Voltage Control Oscillator (Vco)

    Low Band, 800 MHz, PassPort & 900 MHz Theory of Operation: Synthesizer 7-13 7.8.1 Voltage Control Oscillator (VCO) The voltage controlled oscillator block diagram is shown in Figure 7-9. AUX3 (U201 Pin 2) Level Shifter Network AUX4 (U201 Pin 3) TRB_IN Pin 20 Pin 19...

  • Page 78: Trunked Radio Systems

    7.9.1 Privacy Plus Trunked Systems Privacy Plus is a proprietary trunking protocol developed by Motorola which allows a large number of users to share small amounts of frequencies without interfering with each other. The Privacy Plus configuration consists of shared multiple channel repeaters. The Privacy Plus Trunked system includes a Central Controller, which directs the users to the open channels.

  • Page 79: Passport™ Trunked Systems

    Low Band, 800 MHz, PassPort & 900 MHz Theory of Operation: Trunked Radio Systems 7-15 ™ 7.9.4 PassPort Trunked Systems PassPort is an enhanced trunking protocol developed by Trident Microsystems that supports wide area dispatch networking. A network is formed by linking several trunked sites together to form a single system.

  • Page 80: Backlight Driver And Led's

    7-16 Low Band, 800 MHz, PassPort & 900 MHz Theory of Operation: 900 MHz Transmitter 7.9.4.5 BackLight Driver and LED's The logic level signal from the radio microcontroller is translated via Q611 and applied to Q610 which uses Switched Battery Voltage (SWB+) to operate the keypad backlight LED’s. 7.9.4.6 Voice Storage The Voice Storage (VS) can be used to store audio signals coming from the receiver or from the microphone.

  • Page 81: Power Amplifier

    Low Band, 800 MHz, PassPort & 900 MHz Theory of Operation: 900 MHz Transmitter 7-17 The 900 MHz transmitter shown in Figure 7-10 on page 7-16 contains the following basic circuits: • Power amplifier • Antenna switch • Harmonic filter •...

  • Page 82: 900 Mhz Receiver

    7-18 Low Band, 800 MHz, PassPort & 900 MHz Theory of Operation: 900 MHz Receiver U103 and its associated components are part of the temperature cut back circuitry. It senses the printed circuit board temperature around the transmitter circuits and output a DC voltage to the PCIC.

  • Page 83: Receiver Back-End

    Low Band, 800 MHz, PassPort & 900 MHz Theory of Operation: 900 MHz Receiver 7-19 The IF signal coming out of the mixer is transferred to the crystal filter (FL350) through a resistor pad and a diplexer (C312, and L306). Matching to the input of the crystal filter is provided by L353, L354, C377, and C378.

  • Page 84: Hear Clear Routing Of Data/Signaling

    7-20 Low Band, 800 MHz, PassPort & 900 MHz Theory of Operation: 900 MHz Receiver Table 7-2. Hear Clear Logic and IC Status Name Ref. Des Set By RX1* RX2** IC Enable U851-C4 SWB+ Flutter Fighter Enable U851-E3 DACRX LO Clamp Disable U851-A5 SWB+ LO Clamp Disable...

  • Page 85: Frequency Generation Circuitry

    Low Band, 800 MHz, PassPort & 900 MHz Theory of Operation: Frequency Generation Circuitry 7-21 The IF automatic gain control circuit provides approximately 50 dB of attenuation range. The signal strength indicator (RSSI) output of the IF IC produces a voltage that is proportional to the RF level at the IF input to the IF IC.

  • Page 86: 900 Mhz Synthesizer

    7-22 Low Band, 800 MHz, PassPort & 900 MHz Theory of Operation: 900 MHz Synthesizer The Frequency Generation circuitry is comprised of two main ICs, the Low Voltage Fractional-N (LV FracN) synthesizer (U201), and the VCO/Buffer IC (U250). Designed in conjunction to maximize compatibility, the two ICs provide many of the functions that normally would require additional circuitry.

  • Page 87: Figure 7-13. Synthesizer Block Diagram

    Low Band, 800 MHz, PassPort & 900 MHz Theory of Operation: 900 MHz Synthesizer 7-23 Both the normal and adapt charge pumps get their supply from the capacitive multiplier which is made up of CR201, CR202, C244, C245, C246, C247, R200, R218, C208, C243, R219, and R220. Two 3.3 V square waves (180 degrees out of phase) are applied to R219 and R220.

  • Page 88: 900 Mhz Voltage Control Oscillator (Vco)

    7-24 Low Band, 800 MHz, PassPort & 900 MHz Theory of Operation: 900 MHz Voltage Control Oscillator (VCO) 7.14 900 MHz Voltage Control Oscillator (VCO) AUX3 (U201 Pin 2) Level Shifter Network AUX4 (U201 Pin 3) TRB_IN Pin 20 Pin 19 Pin 7 Rx-SW TX/RX/BS...
  • Page 89 Low Band, 800 MHz, PassPort & 900 MHz Theory of Operation: 900 MHz Voltage Control Oscillator (VCO) 7-25 In the receive mode, U250 pin 19 is low or grounded. This activates the receive VCO by enabling the receive oscillator and the receive buffer of U250. The RF signal at U250 pin 8 is run through an injection amplifier, Q304.
  • Page 90 7-26 Low Band, 800 MHz, PassPort & 900 MHz Theory of Operation: 900 MHz Voltage Control Oscillator (VCO)

  • Page 91: Chapter 8 Maintenance

    Chapter 8 Maintenance Introduction This chapter of the manual describes: • Preventive maintenance • Safe handling of CMOS devices • Repair procedures and techniques Preventive Maintenance The radios do not require a scheduled preventive maintenance program; however, periodic visual inspection and cleaning is recommended. Inspection Check that the external surfaces of the radio are clean, and that all external controls and switches are functional.

  • Page 92: Safe Handling Of Cmos And Ldmos

    When damaged parts are replaced, identical parts should be used. If the identical replacement component is not locally available, check the parts list for the proper Motorola part number and order the component from the nearest Motorola Communications parts center listed in the “Piece Parts”...
  • Page 93 Maintenance: General Repair Procedures and Techniques • Chip Components Use either the RLN-4062 Hot-Air Repair Station or the Motorola 0180381B45 Repair Station for chip component replacement. When using the 0180381B45 Repair Station, select the TJ-65 mini- thermojet hand piece. On either unit, adjust the temperature control to 700 degrees F. (370 degrees C), and adjust the airflow to a minimum setting.

  • Page 94: Recommended Test Tools

    8. Remove the circuit board and inspect the repair. No cleaning should be necessary. Recommended Test Tools Table 8-1 lists the recommended tools used for maintaining this family of radios. These tools are also available from Motorola. Table 8-1. Recommended Test Tools Motorola Part Description...

  • Page 95: Replacing The Circuit Board Fuse

    Maintenance: Replacing the Circuit Board Fuse Replacing the Circuit Board Fuse In cases where the radio fails to turn on when power is applied, the circuit board fuse should always be checked as a probable cause of the failure. The locations of the fuse for both the UHF and VHF boards are shown in Figure 8-1 on page 8-6.

  • Page 96: Figure 8-1. Uhf/Vhf/Low Band/800 Mhz/900 Mhz Circuit Board Fuse Locations

    Maintenance: Replacing the Circuit Board Fuse J102 R328 R340 C307 C108 C339 L303 C340 Q301 R304 C3301 R101 C3231 CR303 C341 L304 C3232 C342 C321 C345 C3233 C3242 R305 C311 R347 C314 C334 C347 P100 C3234 C3224 C356 U301 C395 C348 C132 C312...

  • Page 97: Removing And Reinstalling The Circuit Board

    2. Lift the circuit board out of the radio chassis, then remove and discard the thermal pad located between the circuit board and chassis. 3. After repairs, replace the thermal pad (Motorola P/N 7580556Z01) then reinstall the circuit board into the radio chassis.
  • Page 98 Maintenance: Power Up Self-Test Error Codes Table 8-2. Power Up Self-Test Error Codes (Continued) If the error code Then, there is To correct the problem ... displayed is ... a ... No Display improperly connected check connection between main board and display module or display module or replace with new display module.

  • Page 99: Uhf Band 1 Troubleshooting Charts

    Maintenance: UHF Band 1 Troubleshooting Charts 8.10 UHF Band 1 Troubleshooting Charts 8.10.1 Troubleshooting Flow Chart for Controller for all models except PCB 8486458Z03 MCU Check Press PTT. Red LED does not Before replacing light up Power Up Not able to pro- MCU, check SPI Alert Tone gram RF Board...

  • Page 100: Troubleshooting Flow Chart For Controller For Models With Pcb 8486458Z03

    8-10 Maintenance: UHF Band 1 Troubleshooting Charts 8.10.2 Troubleshooting Flow Chart for Controller for models with PCB 8486458Z03 MCU Check Press PTT. Red LED does not Before replacing light up Not able to pro- Power Up MCU, check SPI gram RF Board AUDIO Audio at Alert Tone...

  • Page 101: Troubleshooting Flow Chart For Receiver For All Models Except

    Maintenance: UHF Band 1 Troubleshooting Charts 8-11 8.10.3 Troubleshooting Flow Chart for Receiver for all models except PCB 8486458Z03 (Sheet 1 of 2) START Bad SINAD Bad 20dB Quieting No Recovered Audio Audio at pin Check Controller 27 of U301? Spray of inject 1st IF into XTAL Filter IF Freq: 45.1MHz...

  • Page 102: Troubleshooting Flow Chart For Receiver For All Models Except

    8-12 Maintenance: UHF Band 1 Troubleshooting Charts 8.10.4 Troubleshooting Flow Chart for Receiver for all models except PCB 8486458Z03 (Sheet 2 of 2) Inject RF into J101 Trace IF signal Q302 collec- from L311 to IF Signal at tor OK? Q302.

  • Page 103: Troubleshooting Flow Chart For Receiver, For Models With Pcb 8486458Z03 (Sheet 1 Of 2)

    Maintenance: UHF Band 1 Troubleshooting Charts 8-13 8.10.5 Troubleshooting Flow Chart for Receiver, for models with PCB 8486458Z03 (Sheet 1 of 2) START Bad SINAD Bad 20dB Quieting No Recovered Audio Check Controller Audio at pin 8 of U301? Spray or inject 1st IF 44.85 MHz into XTAL Filter Check Q302 bias...

  • Page 104: Troubleshooting Flow Chart For Receiver, For Models With Pcb 8486458Z03 (Sheet 2 Of 2)

    8-14 Maintenance: UHF Band 1 Troubleshooting Charts 8.10.6 Troubleshooting Flow Chart for Receiver, for models with PCB 8486458Z03 (Sheet 2 of 2) Inject RF into J101 Trace IF signal Q302 collec- from L311 to IF Signal at tor OK? Q302. Check for L311? IF signal bad XTAL filter.

  • Page 105: Troubleshooting Flow Chart For Transmitter

    Maintenance: UHF Band 1 Troubleshooting Charts 8-15 8.10.7 Troubleshooting Flow Chart for Transmitter START No Power Is There B+ Check Q111 Bias for Ant switch Is Control Volt- Check PCIC Is Current age High or Low High Check Drive to Module 1.

  • Page 106: Troubleshooting Flow Chart For Synthesizer

    8-16 Maintenance: UHF Band 1 Troubleshooting Charts 8.10.8 Troubleshooting Flow Chart for Synthesizer Check U248, 3.3V at U201 Start L201 & L202 pins 5, 20, 34 & 36 Visual Check CR201, Correct check of the U210, U211, C258, Problem Board OK? C259 &...

  • Page 107: Troubleshooting Flow Chart For Vco

    Maintenance: UHF Band 1 Troubleshooting Charts 8-17 8.10.9 Troubleshooting Flow Chart for VCO START Change U241 No LO? Change L253 O/C? L253 Pin 10 TRB = 5V? Tx Carrier? >1V? VCO OK Check R245 for dry joint or faulty AUX 3 Check High? R260...

  • Page 108: Uhf Band 2 Troubleshooting Charts

    8-18 Maintenance: UHF Band 2 Troubleshooting Charts 8.11 UHF Band 2 Troubleshooting Charts 8.11.1 Troubleshooting Flow Chart for Controller for all models except those with PCB 8486686Z02 MCU Check Press PTT. Red LED does not Before replacing light up Power Up Not able to pro- MCU, check SPI Alert Tone...

  • Page 109: Troubleshooting Flow Chart For Controller For Models With Pcb 8486686Z02

    Maintenance: UHF Band 2 Troubleshooting Charts 8-19 8.11.2 Troubleshooting Flow Chart for Controller for models with PCB 8486686Z02 MCU Check Press PTT. Red LED does not Before replacing light up Not able to pro- Power Up MCU, check SPI gram RF Board AUDIO Audio at Alert Tone...

  • Page 110: Troubleshooting Flow Chart For Receiver, For All Models Except Those With Pcb 8486686Z02 (Sheet 1 Of 2)

    8-20 Maintenance: UHF Band 2 Troubleshooting Charts 8.11.3 Troubleshooting Flow Chart for Receiver, for all models except those with PCB 8486686Z02 (Sheet 1 of 2) START Bad SINAD Bad 20dB Quieting No Recovered Audio Audio at pin Check Controller 27 of U301? Spray of inject 1st IF into XTAL Filter IF Freq: 45.1MHz...

  • Page 111: Troubleshooting Flow Chart For Receiver, For All Models Except Those With Pcb 8486686Z02 (Sheet 2 Of 2)

    Maintenance: UHF Band 2 Troubleshooting Charts 8-21 8.11.4 Troubleshooting Flow Chart for Receiver, for all models except those with PCB 8486686Z02 (Sheet 2 of 2) Inject RF into J101 Trace IF signal Q302 collec- from L311 to IF Signal at tor OK? Q302.

  • Page 112: Troubleshooting Flow Chart For Receiver, For Models With Pcb 8486686Z02 (Sheet 1 Of 2)

    8-22 Maintenance: UHF Band 2 Troubleshooting Charts 8.11.5 Troubleshooting Flow Chart for Receiver, for models with PCB 8486686Z02 (Sheet 1 of 2) START Bad SINAD Bad 20dB Quieting No Recovered Audio Check Controller Audio at pin 8 of U301? Spray or inject 1st IF 44.85 MHz into XTAL Filter Check Q302 bias...

  • Page 113: Troubleshooting Flow Chart For Receiver, For Models With Pcb 8486686Z02 (Sheet 2 Of 2)

    Maintenance: UHF Band 2 Troubleshooting Charts 8-23 8.11.6 Troubleshooting Flow Chart for Receiver, for models with PCB 8486686Z02 (Sheet 2 of 2) Inject RF into J101 Trace IF signal Q302 collec- from L311 to IF Signal at tor OK? Q302. Check for L311? IF signal bad XTAL filter.

  • Page 114: Troubleshooting Flow Chart For Transmitter

    8-24 Maintenance: UHF Band 2 Troubleshooting Charts 8.11.7 Troubleshooting Flow Chart for Transmitter START No Power Is There B+ Check Q111 Bias for Ant switch Is Control Volt- Check PCIC Is Current age High or Low High Check Drive to Module 1.

  • Page 115: Troubleshooting Flow Chart For Synthesizer

    Maintenance: UHF Band 2 Troubleshooting Charts 8-25 8.11.8 Troubleshooting Flow Chart for Synthesizer Check U248, 3.3V at U201 Start L201 & L202 pins 5, 20, 34 & Visual Check CR201, U210, Correct check of the U211, C258, C259 & Problem Board OK? C228 16.8MHz...

  • Page 116: Troubleshooting Flow Chart For Vco

    8-26 Maintenance: UHF Band 2 Troubleshooting Charts 8.11.9 Troubleshooting Flow Chart for VCO START Change U241 No LO? Change L253 O/C? L253 Pin 10 TRB = 5V? Tx Carrier? >1V? VCO OK Check R245 for dry joint or faulty AUX 3 Check High? R260...

  • Page 117: Vhf Troubleshooting Charts

    Maintenance: VHF Troubleshooting Charts 8-27 8.12 VHF Troubleshooting Charts 8.12.1 Troubleshooting Flow Chart for Controller for all models except those with PCB 8486473Z04 MCU Check Press PTT. Red LED does not Before replacing light up Power Up Not able to pro- MCU, check SPI Alert Tone gram RF Board...

  • Page 118: Troubleshooting Flow Chart For Controller For Models With Pcb 8486473Z04

    8-28 Maintenance: VHF Troubleshooting Charts 8.12.2 Troubleshooting Flow Chart for Controller for models with PCB 8486473Z04 MCU Check Press PTT. Red LED does not Before replacing light up Power Up Not able to pro- MCU, check SPI Audio Alert Tone gram RF Board AUDIO clock, SPI data,...

  • Page 119: Except Those With Pcb 8486473Z04

    Maintenance: VHF Troubleshooting Charts 8-29 8.12.3 Troubleshooting Flow Chart for Receiver, for all models except those with PCB 8486473Z04 (Sheet 1 of 2) START Bad SINAD Bad 20dB Quieting No Recovered Audio Audio at pin Check Controller 27 of U3220? Spray of inject 1st IF into XTAL Filter IF Freq: 45.1MHz...

  • Page 120: Troubleshooting Flow Chart For Receiver, For All Models Except Those With Pcb 8486473Z04 (Sheet 2 Of 2)

    8-30 Maintenance: VHF Troubleshooting Charts 8.12.4 Troubleshooting Flow Chart for Receiver, for all models except those with PCB 8486473Z04 (Sheet 2 of 2) Inject RF into J3501 Trace IF signal Q3200 collec- from C3200 to IF Signal at tor OK? Q3200.

  • Page 121: Troubleshooting Flow Chart For Receiver For Models With Pcb 8486473Z04 (Sheet 1 Of 2)

    Maintenance: VHF Troubleshooting Charts 8-31 8.12.5 Troubleshooting Flow Chart for Receiver for models with PCB 8486473Z04 (Sheet 1 of 2) START Bad SINAD Bad 20dB Quieting No Recovered Audio Check Controller (in the case of no audio) Audio at pin 8 OR ELSE go to “B”...

  • Page 122: Troubleshooting Flow Chart For Receiver For Models With Pcb 8486473Z04 (Sheet 2 Of 2)

    8-32 Maintenance: VHF Troubleshooting Charts 8.12.6 Troubleshooting Flow Chart for Receiver for models with PCB 8486473Z04 (Sheet 2 of 2) Inject RF into J3501 Trace IF signal Q3200 collec- from L3200 to IF Signal at tor OK? Q3200. Check for L3200? IF signal bad XTAL filter.

  • Page 123: Troubleshooting Flow Chart For Transmitter

    Maintenance: VHF Troubleshooting Charts 8-33 8.12.7 Troubleshooting Flow Chart for Transmitter START No Power Is There B+ Check Bias for Ant Q3561 switch Is Control Is Current Check PCIC Voltage high or low? High Check Drive to Module 1. Check Pin Diodes 2.

  • Page 124: Troubleshooting Flow Chart For Synthesizer

    8-34 Maintenance: VHF Troubleshooting Charts 8.12.8 Troubleshooting Flow Chart for Synthesizer Check U3201, 3.3V at U3701 Start L3731 pins 5, 20, 34 & 36 Visual Check D3701, Correct check of the D3702, U3701, Problem Board OK? C3701 - C3707 16.8MHz Is 16.8MHz Is U3701 Pin 47 Replace...

  • Page 125: Troubleshooting Flow Chart For Vco

    Maintenance: VHF Troubleshooting Charts 8-35 8.12.9 Troubleshooting Flow Chart for VCO START Change U3801 L3831, L3832, Change No LO? L3833 L3831, L3832 O/C? Pin 10 TRB = 3.2V? Tx Carrier? >1V? VCO OK Check R3811, L3811 for faulty parts and dry joints AUX 3 Check High?

  • Page 126: Low Band Troubleshooting Charts

    8-36 Maintenance: Low Band Troubleshooting Charts 8.13 Low Band Troubleshooting Charts 8.13.1 Troubleshooting Flow Chart for Controller MCU Check Press PTT. Red LED does not Before replacing light up Power Up Not able to pro- MCU, check SPI Alert Tone gram RF Board AUDIO Audio at...

  • Page 127: Troubleshooting Flow Chart For Receiver (Sheet 1 Of 2)

    Maintenance: Low Band Troubleshooting Charts 8-37 8.13.2 Troubleshooting Flow Chart for Receiver (Sheet 1 of 2) START Bad SINAD Bad 20dB Quieting No Recovered Audio Check Controller Audio at pin 27 of U303? Spray of inject 1st IF into XTAL Filter IF Freq: 109.65 MHz Check Q301 bias cir- cuitry for faults.

  • Page 128: Troubleshooting Flow Chart For Receiver (Sheet 2 Of 2)

    8-38 Maintenance: Low Band Troubleshooting Charts 8.13.3 Troubleshooting Flow Chart for Receiver (Sheet 2 of 2) Inject RF into J101 Trace IF signal from L301 to U301 drain OK? IF Signal at U301. Check for IF signal L301? bad XTAL filter present? Before replacing U303, check U303...

  • Page 129: Troubleshooting Flow Chart For Transmitter

    Maintenance: Low Band Troubleshooting Charts 8-39 8.13.4 Troubleshooting Flow Chart for Transmitter START No Power Is control voltage at Is Current ~ Check PCIC U101 Pin 1 > 5 2 A? Check input to U101, Pin 16 1. Check Pin Diodes 2.

  • Page 130: Troubleshooting Flow Chart For Synthesizer

    8-40 Maintenance: Low Band Troubleshooting Charts 8.13.5 Troubleshooting Flow Chart for Synthesizer Check U200 3.3V at U205 Start and L225 pins 5, 20, 34 & 36 Visual Correct check of the Problem Board OK? Check C247, C249, Is 17.0 MHz 17.0MHz Is U205 Pin Replace...

  • Page 131: Troubleshooting Flow Chart For Vco

    Maintenance: Low Band Troubleshooting Charts 8-41 8.13.6 Troubleshooting Flow Chart for VCO No RX LO or No sig- No TX LO or No sig- nal at U205 Pin 32 in nal at U205 Pin 32 in Check signal at Check signal at collector of Q201 collector of Q201 Check L204, L211, L212,...

  • Page 132: 800 Mhz Troubleshooting Charts

    8-42 Maintenance: 800 MHz Troubleshooting Charts 8.14 800 MHz Troubleshooting Charts 8.14.1 Troubleshooting Flow Chart for Controller MCU Check Press PTT. Red LED does not light Power Up Before replacing MCU, AUDIO Not able to pro- Audio at Alert Tone check SPI clock, SPI gram RF Board Audio PA (U420)

  • Page 133: Troubleshooting Flow Chart For Receiver (Sheet 1 Of 2)

    Maintenance: 800 MHz Troubleshooting Charts 8-43 8.14.2 Troubleshooting Flow Chart for Receiver (Sheet 1 of 2) START Bad SINAD Bad 20dB Quieting No Recovered Audio Audio at Check Controller pin 27 of U351? Spray or inject 1st IF into XTAL Filter IF Freq: 109.65 MHz Check Q350 bias cir-...

  • Page 134: Troubleshooting Flow Chart For Receiver (Sheet 2 Of 2)

    8-44 Maintenance: 800 MHz Troubleshooting Charts 8.14.3 Troubleshooting Flow Chart for Receiver (Sheet 2 of 2) Inject RF into J101 Trace IF signal from Is the level of the L353 to U352. IF signal of the IF Signal at Check for bad XTAL output of U352 as L353? filter.

  • Page 135: Troubleshooting Flow Chart For Transmitter

    Maintenance: 800 MHz Troubleshooting Charts 8-45 8.14.4 Troubleshooting Flow Chart for Transmitter START Low Power No Power No Power out or Low Power Is overall radio current between 0.8 and 1.3 A when transmit- ting? Is the fuse Is there a Replace F501 Check L101, L102, C101, F501 OK?

  • Page 136: Troubleshooting Flow Chart For Synthesizer

    8-46 Maintenance: 800 MHz Troubleshooting Charts 8.14.5 Troubleshooting Flow Chart for Synthesizer Check U248 3.3V at U201 Start & L202 pins 5, 20, 34 & 36 Visual Check D201, D202, Correct check of the C244, C245, C246 & Problem Board OK? C247.

  • Page 137: Troubleshooting Flow Chart For Vco

    Maintenance: 800 MHz Troubleshooting Charts 8-47 8.14.6 Troubleshooting Flow Chart for VCO START Is Tx signal Is LO signal VCO is OK. present at the PA present at the driver IC, U101? mixer IC U301? Resolder or Is resonator IC replace U205.

  • Page 138: Passport Trunking Troubleshooting Chart

    8.15 PassPort Trunking Troubleshooting Chart Start Check Radio Operation on a Non PassPort Zone with a Conventional Personality without the Option Board Enabled Check Radio PassPort Programming using CPS Check Switched Battery and Vdd from Radio on PTCB Check Radio PassPort Programming using CPS Demod on J601-6...

  • Page 139: Keypad Troubleshooting Chart

    Maintenance: Keypad Troubleshooting Chart 8-49 8.16 Keypad Troubleshooting Chart Disconnect and Display reconnect 18-pin flex IF STILL START Keypad Disconnect and reconnect 40-pin flex...

  • Page 140: Mhz Troubleshooting Charts

    8-50 Maintenance: 900 MHz Troubleshooting Charts 8.17 900 MHz Troubleshooting Charts 8.17.1 Troubleshooting Flow Chart for Controller (Sheet 1 of 2) Press PTT. Red LED does not light AUDIO Audio at Audio PA (U420) J403 Audio at input Pin 2 & Pin 3. (C447).

  • Page 141: Troubleshooting Flow Chart For Controller (Sheet 2 Of 2)

    Maintenance: 900 MHz Troubleshooting Charts 8-51 8.17.2 Troubleshooting Flow Chart for Controller (Sheet 2 of 2) MCU Check. Before replacing MCU, Power Up Not able to pro- check SPI clock, SPI Alert Tone gram RF Board data, and RF IC ICs.

  • Page 142: Troubleshooting Flow Chart For Receiver (Sheet 1 Of 2)

    8-52 Maintenance: 900 MHz Troubleshooting Charts 8.17.3 Troubleshooting Flow Chart for Receiver (Sheet 1 of 2) START Bad SINAD. Bad 20dB Quieting. No Recovered Audio Audio at Check Controller. pin 27 of U351? Spray or inject 1st IF into XTAL Filter.

  • Page 143: Troubleshooting Flow Chart For Receiver (Sheet 2 Of 2)

    Maintenance: 900 MHz Troubleshooting Charts 8-53 8.17.4 Troubleshooting Flow Chart for Receiver (Sheet 2 of 2) Inject RF into J101 Trace IF signal from Is the level of the L353 to U352. IF Signal at IF signal of the Check for bad XTAL L353? output of U352 as filter...
  • Page 144 8-54 Maintenance: 900 MHz Troubleshooting Charts 8.17.5 Troubleshooting Flow Chart for Transmitter START Low Power No Power No Power out or Low Power. Is overall Check C163, radio current Replace C127, and between 0.8 and parts. C142 for open 1.3 A when circuit.
  • Page 145 Maintenance: 900 MHz Troubleshooting Charts 8-55 8.17.6 Troubleshooting Flow Chart for Synthesizer Check U24 3.3V at U201 Start L202. pins 5, 20, 34 & 36. Visual Check D201, D202, Correct check of the C244, C245, C246 & Problem. Board OK? C247.

  • Page 146: Troubleshooting Flow Chart For Vco

    8-56 Maintenance: 900 MHz Troubleshooting Charts 8.17.7 Troubleshooting Flow Chart for VCO START Is Tx signal Is LO signal VCO is OK. present at the PA present at the driver IC, U101? mixer IC U301? Resolder or Is resonator replace U205. FL201 soldered Is resonator Resolder or...

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