Motorola GP640 Service Information
Gp600 series
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Also See for GP640:
- Basic user's manual (154 pages) ,
- User manual (32 pages) ,
- Specification sheet (2 pages)
Related Manuals for Motorola GP640
Summary of Contents for Motorola GP640
- Page 1 Professional Radio GP Series UHF2 (450 - 527MHz) Service Information Issue: March 2001...
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Page 2: Computer Software Copyrights
Accordingly, any copyrighted Motorola computer programs contained in the Motorola products described in this manual may not be copied or reproduced in any manner without the express written permission of Motorola. Furthermore, the purchase of Motorola... -
Page 3: Table Of Contents
Table of Contents Chapter 1 MODEL CHART AND TECHNICAL SPECIFICATIONS 1.0 GP640/GP680 Model Chart .................1-1 2.0 GP1280 Model Chart ...................1-1 3.0 Technical Specifications ..................1-2 Chapter 2 THEORY OF OPERATION 1.0 Introduction ......................2-1 2.0 UHF2 Transmitter ....................2-1 2.1 Power Amplifier ....................2-1 2.2 Antenna Switch....................2-2... -
Page 5: Model Chart And Technical Specifications
Chapter 1 MODEL CHART AND TECHNICAL SPECIFICATIONS GP640/GP680 Model Chart Professional GP600 Series (UHF2) Model Description MDH25SDC9CK3_E GP640 UHF2 450-527 MHz 4W MDH25SDH9CK6_E GP680 UHF2 450-527 MHz 4W Item Description PMLE4122_ GP640 UHF2 Back Cover Kit PMLE4123_ GP680 UHF2 Back Cover Kit... - Page 6 MODEL CHART AND TECHNICAL SPECIFICATIONS Technical SpeciÞcations Data is speciÞed for +25¡C unless otherwise stated. General SpeciÞcations Channel Capacity GP640 16 (Conventional) GP680 16 (Conventional) GP1280 16 (Conventional) Power Supply Rechargeable battery 7.5v Dimensions: H x W x D (mm) Height excluding knobs...
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Page 7: Technical Specifications
Technical Specifications Transmitter UHF2 *Frequencies - Full Bandsplit 450-527 MHz Channel Spacing 12.5/20/25 kHz Frequency Stability ±2.5 ppm @ 12.5kHz (-25¡C to +55¡C, +25¡ Ref.) ±5ppm @ 25 kHz Power 450 - 527 MHz: 1-4W ±2.5 @ 12.5 kHz Modulation Limiting ±4.0 @ 20 kHz ±5.0 @ 25 kHz FM Hum &... - Page 8 MODEL CHART AND TECHNICAL SPECIFICATIONS...
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Page 9: Theory Of Operation
Chapter 2 THEORY OF OPERATION Introduction This Chapter provides a detailed theory of operation for the UHF2 circuits in the radio. For details of the theory of operation and trouble shooting for the the associated Controller circuits refer to the Controller Section of this manual. -
Page 10: Antenna Switch
THEORY OF OPERATION The LDMOS PA is capable of supplying an output power of 7W with an input signal of 0.3W. The current drain is typically 1300mA while operating in the frequency range of 450-527 MHz. The power output can be varied by changing the bias voltage. 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 and R170). -
Page 11: Uhf2 Receiver
UHF2 Receiver UHF2 Receiver The UHF2 receiver consists of a front end, back end, and automatic gain control circuits. A block diagram of the receiver is shown in Figure 2-2. Detailed descriptions of these features are contained in the paragraphs that follow. Antenna Pin Diode Varactor... -
Page 12: Receiver Back-End
THEORY OF OPERATION The output of the bandpass Þlter is coupled to the RF ampliÞer transistor Q301 via C307. After being ampliÞed by the RF ampliÞer, the RF signal is further Þltered by a second varactor tuned bandpass Þlter, consisting of L306, L307, C313, C317, CR304 and CR305. Both the pre and post-RF ampliÞer varactor tuned Þlters have similar responses. -
Page 13: Automatic Gain Control (Agc)
UHF2 Receiver Automatic Gain Control (AGC) ( Refer to the UHF2 Receiver Front End and Receiver Back End schematic diagrams ) The front end automatic gain control circuit provides automatic reduction of gain, of the front end RF ampliÞer via feedback. This action is necessary to prevent overloading of backend circuits. This is achieved by drawing some of the output power from the RF ampliÞer output. -
Page 14: Frequency Generation Circuit
THEORY OF OPERATION Frequency Generation Circuit ( Refer to Figure 2-3 and the UHF2 Frequency Synthesizer schematic diagram ) The frequency generation circuit, shown in Figure 2-3, is composed of Fractional-N synthesizer U201 and VCO/Buffer IC U241. Designed in conjunction to maximize compatibility, the two ICs provide many of the functions that normally require additional circuitry. -
Page 15: Synthesizer
Frequency Generation Circuit Synthesizer ( Refer to Figure 2-4 and the UHF2 Synthesizer schematic diagram) The Fractional-N synthesizer, shown in Figure 2-4, uses a 16.8 MHz crystal (FL201) to provide a reference for the system. The LVFractN IC (U201) further divides this to 2.1MHz, 2.225MHz, and 2.4MHz to be used as reference frequencies. -
Page 16: Voltage Control Oscillator (Vco)
THEORY OF OPERATION Voltage Control Oscillator (VCO) ( Refer to Figure 2-5 and the UHF2 Voltage Controlled Oscillator schematic diagram) The VCOB IC (U241), shown in Figure 2-5, 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 are enabled. - Page 17 Frequency Generation Circuit Table 2-1 Level Shifter Logic Desired AUX 4 AUX 3 Mode High (@3.2V) High (@4.8V) High Battery Saver Hi-Z/Float (@2.5V) In the receive mode, U241 pin 19 is low or grounded. This activates the receive VCO by enabling the receive oscillator and the receive buffer of U241.
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Page 18: Voice Storage (Gp1280 Only)
( Refer to Figure 2-6 and the UHF2 Voice Storage schematic diagram) The Voice Storage feature is offered as standard in the GP1280 and as an Option board for GP340/GP360/GP380 and GP640/GP680 models. The Voice Storage feature enables users to: Record and Playback Personal Memo (Reminders, Notes, etc.). - Page 19 Voice Storage (GP1280 Only) 2-11 Audio routing to the Voice Storage circuitry during receive message recording, message playback, personal memo recording and voice prompt transmit over the air are as follows: Received Message Recording The receive audio is tapped from the Rx_Aud_Rtn pin of the ASFIC_CMP during receive mode. Message Playback Message playback is via the FLAT_RX_SND pin of ASFIC_CMP.
- Page 20 2-12 THEORY OF OPERATION...
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Page 21: Troubleshooting Charts
Chapter 3 TROUBLESHOOTING CHARTS Troubleshooting Flow Chart for Receiver (Sheet 1 of 2) START Bad SINAD Bad 20dB Quieting No Recovered Audio udio Check Controller at pin 27 of U301? Spray of inject 1st IF into XTAL Filter IF Freq: 45.1MHz Check Q320 bias circuitry for faults. -
Page 22: Troubleshooting Flow Chart For Receiver (Sheet 2 Of 2)
TROUBLESHOOTING CHARTS Troubleshooting Flow Chart for Receiver (Sheet 2 of 2) Inject RF into J101 Q302 Trace IF signal collector OK? IF Signal from L311 to IF signal at L311? Q302. Check for present? bad XTAL Þlter. Before replacing U301, check U301 voltages;... -
Page 23: Troubleshooting Flow Chart For Transmitter
Troubleshooting Flow Chart for Transmitter Troubleshooting Flow Chart for Transmitter START No Power Is There B+ Bias for Check Q111 Ant switch CR101 Is Current Is Control Voltage High Check PCIC or Low at C119 High Check Drive to 1. Check Pin Diodes Module 2. -
Page 24: Troubleshooting Flow Chart For Synthesizer
TROUBLESHOOTING CHARTS Troubleshooting Flow Chart for Synthesizer 3.3V at Start Check U248, U201 pins 5, L201 & L202 20, 34& Check CR201, Visual U210, U211, Correct check of the C258, C259 & Problem Board OK? C228 Is U201 16.8MHz 16.8MHz at pin 6 of Pin47 AT = Replace... -
Page 25: Troubleshooting Flow Chart For Vco
Troubleshooting Flow Chart for VCO Troubleshooting Flow Chart for VCO START No LO? U241 Check R245 TRB = for dry joint Pin 10 5V? @U241 Carrier? or faulty >1V? Pin 19 VCO OK L253 Change Open L253 Circuit? AUX 3 Check High? R260... - Page 26 TROUBLESHOOTING CHARTS...
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Page 27: Allocation Of Schematics And Circuit Boards
Chapter 4 UHF2 PCB/SCHEMATICS/PARTS LISTS Allocation of Schematics and Circuit Boards Controller Circuits The UHF2 circuits are contained on the printed circuit board (PCB) which also contains the Controller circuits. This Chapter shows the schematics for the UHF2 circuits only, refer to the Controller section for details of the related Controller circuits.The PCB component layouts and the Parts Lists in this Chapter show both the Controller and UHF2 circuit components. - Page 28 UHF2 PCB/SCHEMATICS/PARTS LISTS...