TM-V71A_E_serv.pdf

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1、SERVICE MAN UAL 144/430 (440) MHz FM DUAL BANDER TM-V71A/V71E 2007-5 PRINTED IN JA PAN B51-8791-00 (N) 289 This product uses Lead Free solder.This product complies with the RoHS directive for the European market. Photo is TM-V71A. CONTENTS DISASSEMBLY FOR REPAIR .2 CIRCUIT DESCRIPTION .3 SEMICONDUCT

2、OR DATA .11 COMPONENTS DESCRIPTION .14 TERMINAL FUNCTION .19 PARTS LIST .22 EXPLODED VIEW .38 PACKING .39 ADJUSTMENT .40 PC BOARD DISPLAY UNIT (X54-3590-00) .60 TX-RX UNIT (X57-731X-XX) .64 INTERCONNECTION DIAGRAM .72 SCHEMATIC DIAGRAM .74 BLOCK DIAGRAM .86 LEVEL DIAGRAM .88 OPTIONAL ACCESSORIES .90

3、 SPECIFICATIONS .91 Microhone (T91-0657-15) Metallic cabinet (A01-2206-02) Front glass (Display) (B10-2775-12) Panel (Display) (A62-1135-03) Knob (ENC) (K29-9376-03) Knob (VOL) (K29-9377-03) x 2 Knob (SQL) (K29-9380-03) x 2 Button knob (VFO,MR) (K29-9378-03) Button knob (POWER,PM) (K29-9379-03) Butt

4、on knob (7KEYS) (K29-9381-02) TM-V71A/V71E 2 Document Copyrights Copyright 2007 by Kenwood Corporation. All rights reserved. No part of this manual may be reproduced, translated, distributed, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, f

5、or any purpose without the prior written permission of Kenwood. Disclaimer While every precaution has been taken in the preparation of this manual, Kenwood assumes no responsibility for errors or omissions. Neither is any liability assumed for damages resulting from the use of the information contai

6、ned herein. Kenwood reserves the right to make changes to any products herein at any time for improvement purposes. DISASSEMBLY FOR REPAIR Precautions for Disassembly When removing the rear case from the panel, open the bottom side slowly so as not to stress the FPC, as the FPC on the rear case is c

7、onnected with the connector of the display PCB. Display PCB FPC Panel Rear case TM-V71A/V71E 3 1. Frequency Confi guration The TM-V71A/V71E has an individual VCO and PLL unit for both band A and band B. Using these separate VCO and PLL circuits, it can receive 2 separate bands at the same time. You

8、can also perform full-duplex operation. The band A VCO is used for the following functions: (i) VHF/UHF transmission (ii) The first local oscillator for the band A (VHF) reception. (iii) The first local oscillator for the band A (UHF) reception. The band B VCO is used for the following functions: (i

9、) VHF/UHF transmission (ii) The first local oscillator for the band B (VHF) reception. (iii) The first local oscillator for the band B (UHF) reception. The PLL reference frequency is generated by a 12.8MHz (band A) and a 16.8MHz (band B) crystal oscillator connected to the band A and band B PLL ICs.

10、 This reference frequency is used for both PLL circuits. The 45.505MHz second local oscillator for band A is generated by the FM IC crystal oscillator circuit. The second local oscillator for the band B uses the tripled 16.8MHz reference oscillator frequency. Note: The PCB layout and the mounting pa

11、rts are the same for the band A VCO (X57-731 B/6) and band B VCO (X57-731 C/6), although the PCB silk print is different. AF AMP TCXO 16.8MHz PLL B MIC AMP VCO B MCF 49.95MHz 2dn IF 450kHz DET x3 FM IC 50.4MHz TCXO 12.8MHz Band A VHF RX VHF TX PLL AVCO A MCF 45.05MHz 2dn IF 455kHz DET FM IC 45.505MH

12、z 1st IF 45.05MHz 1st IF 49.95MHz CA A Band A UHF RX DB B Band B VHF RX UHF TX EA Band B UHF RX FB MIC SP ANT Fig. 1 Frequency confi guration K typeE typeM4 type A144.000 147.995MHz144.000145.995MHz144.000145.995MHz B438.000449.995MHz430.000439.995MHz430.000439.995MHz C189.050193.045MHz189.050191.04

13、5MHz189.050191.045MHz D392.950404.945MHz384.950394.945MHz384.950394.945MHz E193.950197.945MHz193.950195.945MHz193.950195.945MHz F388.050400.045MHz380.050390.045MHz380.050390.045MHz CIRCUIT DESCRIPTION TM-V71A/V71E 4 2. Receiver System 2-1. Band A VHF Receiver Circuit The incoming signal from the ant

14、enna passes through a filter circuit and goes to the RF amplifier (Q228). The amplifi ed signal enters the band-pass fi lter. After the signal passes through the band-pass fi lter, it is amplifi ed by another RF amplifier (Q227) and then passes through the band- pass fi lter before entering the mixe

15、r (Q226). The frequency of the signal is converted by the fi rst local oscillator (Upper heterodyne) to generate a 45.05MHz first IF signal. The signal passes through the MCF (XF486), is amplifi ed by the IF amplifi er (Q495) and then enters the FM IC (IC486). The signal is converted to the 455kHz s

16、econd IF signal by the second local oscillator (Upper heterodyne). It is then detected to generate an audio signal. 2-2. Band B VHF Receiver Circuit The incoming signal from the antenna passes through a filter circuit and goes to the RF amplifier (Q293). The amplifi ed signal passes through the band

17、-pass fi lter and is amplified by another RF amplifier (Q292). It then passes through the band-pass fi lter and goes to the mixer (Q291). The frequency of the signal is converted by the fi rst local oscillator (Upper heterodyne) to generate a 49.95MHz fi rst IF signal. The signal passes through the

18、MCF (XF546), is amplified by the IF amplifier (Q551) and then enters the FM IC (IC546). The signal is then converted to the 450kHz second IF signal by the second local oscillator, which is tripled 16.8MHz (Upper heterodyne). It is then detected to generate an audio signal. Fig. 2 Band A and Band B V

19、HF receiver circuit ANT SW D/A AIP SW D134,135 D186,188LPF RF AMP Q228 RF AMP Q227 IF AMP Q495 X486 45.505MHz MIXER Q226 MCF XF486 CF Wide IC576 Q229 BPF D241243 L248,249,258 BPF D238240 L245,257 BPF D232234 L232,236,250 BPF D229231 L232,233,260 CF Narrow IC667 SW IC576 MPU IC918 FM IC IC486 1st Loc

20、al OSC Band A Band B 2nd Local OSC Band A AF D/A AIP SW RF AMP Q293 RF AMP Q292 IF AMP Q551 MIXER Q291 MCF XF546 CF Wide IC576 Q294 BPF D306308 L312314 BPF D303305 L309,310,322 BPF D297299 L301,302,323 BPF D294296 L297,298,324 CF Narrow IC667 SW IC577 MPU IC918 FM IC IC546 1st Local OSC 2nd Local OS

21、C Band B AF 45.05MHz 49.95MHz TCXO X66 Tripler x3 16.8MHzQ547 2-3. Band A UHF Receiver Circuit The incoming signal from the antenna passes through a filter circuit and goes to the RF amplifier (Q363). The amplified signal enters the band-pass filter. After the signal passes through the band-pass fil

22、ter, it is amplified by another RF amplifier (Q362) and then passes through the band-pass filter before entering the mixer (Q361). The frequency of the signal is converted by the fi rst local oscillator (Lower heterodyne) to generate a 45.05MHz fi rst IF signal. The signal passes through the MCF (XF

23、486), is amplifi ed by the IF amplifi er (Q495) and then enters the FM IC (IC486). The signal is converted to the 455kHz second IF signal by the second local oscillator (Upper heterodyne). It is then detected to generate an audio signal. 2-4. Band B UHF Receiver Circuit The incoming signal from the

24、antenna passes through a filter circuit and goes to the RF amplifier (Q408). The amplifi ed signal passes through the band-pass fi lter and is amplified by another RF amplifier (Q407). It then passes through the band-pass fi lter and goes to the mixer (Q406). The frequency of the signal is converted

25、 by the fi rst local oscillator (Lower heterodyne) to generate a 49.95MHz fi rst IF signal. The signal passes through the MCF (XF546), is amplified by the IF amplifier (Q551) and then enters the FM IC (IC546). The signal is then converted to the 450kHz second IF signal by the second local oscillator

26、, which is tripled 16.8MHz (Upper heterodyne). It is then detected to generate an audio signal. The VHF/ UHF band-pass filter is tuned to the desired frequency according to the BPF voltage output from the D/A IC (IC667), and is controlled by the MPU (IC918) and the varicap. CIRCUIT DESCRIPTION TM-V7

27、1A/V71E 5 2-5. Audio Circuit The detected band A audio signal is amplifi ed by Q810 and de-emphasized by Q806. The band B audio signal is amplified by Q811 and de-emphasized by Q807. One of these audio signals is selected with a cross point switch (IC806). The signal passes through the electronic vo

28、lume ANT SW D/A AIP SW D164,165 D187,189LPF RF AMP Q363 RF AMP Q362 IF AMP Q495 X486 45.505MHz MIXER Q361 MCF XF486 CF Wide IC576 Q400 BPF D378,379 L377 BPF D375,376 L375 BPF D370,371 L370 BPF D364,365 L366 BPF D367,368 L368 CF Narrow IC667 MPU IC918 FM IC IC486 1st Local OSC Band A Band B 2nd Local

29、 OSC Band A AF 2nd Local OSC 45.05MHz D/A AIP SW RF AMP Q408 RF AMP Q407 IF AMP Q551 MIXER Q406 MCF XF546 CF Wide IC576 Q450 BPF D423,424 L422 BPF D420,421 L420 BPF D415,416 L415 BPF D409,410 L411 BPF D412,413 L413 CF Narrow IC667 MPU IC918 FM IC IC546 1st Local OSC Band B AF 49.95MHz TCXO X66 Tripl

30、er x3 16.8MHzQ547 Fig. 3 Band A and Band B UHF receiver circuit Q807Q811 IC805 1/2 IC805 1/2 DE-EMPHASIS B Q806 Q804Q803 Q810 DE-EMPHASIS A IC918 MPU CTCSS Filter AMP BEEP DTMF IC806 Cross Point SW IC804 E VR MUTE1 MUTE2 ATT IC801 AF AMPJ801 (SP1) J802 (SP2) IC666 Multi SW IC486 FM IC (A) IC546 FM I

31、C (B) Q816 Fig. 4 Audio circuit (IC804), is amplifi ed by the AF amplifi er (IC801), and is then fed to the speaker or the external speaker jack. CTCSS and DCS signals that pass through the filter circuit (IC805) go to the MPU (IC918) for CTCSS and DCS decoding. 3. Transmitter System 3-1. Modulation

32、 Circuit The audio modulation input from the microphone is amplifi ed by IC802. After the DTMF signal and 1750Hz tone signal generated by the MPU are switched with IC806, they are mixed by IC803. After the signal amplified by IC802 is switched by IC806, it is amplifier by IC803. The signal is then p

33、re-emphasized by Q805 and Q808, and its level is adjusted by IC804. The resulting signal goes to each of the band A and band B VCOs as a modulation signal. The TONE/ DCS signal generated by the MPU is fed to IC803. The signal amplifi ed by IC803 is distributed and the level is adjusted by IC804. The

34、 modulating signal goes to each of the band A and band B VCOs and the reference oscillation circuit. CIRCUIT DESCRIPTION TM-V71A/V71E 6 3-2. Transmitter Circuit The VHF VCO output is amplifi ed by RF amplifi er (Q644) and driver amplifi er (Q131). It is further amplifi ed to the fi nal output by pow

35、er module (IC131). The output signal passes through antenna switch (D134, D135) and a low-pass fi lter, and is then fed to the antenna. The UHF VCO output is amplifi ed by RF amplifi er (Q161) and driver amplifi er (Q162). It is further amplifi ed to the fi nal output by power module (IC161). The si

36、gnal passes through antenna switch (D164, D165), and a low-pass and high-pass fi lter, and is then fed to the antenna. IC802 1/2 Q805 Q801 Q808 PRE-EMPHASIS IC806 Cross Point SW MIC AMP IC802 1/2 IC803 1/2 ALC AMP IC803 2/2 MOD AMP X1 TCXO (A) X66 TCXO (B) VCO (A) VCO (B) IC804 E VRIC807 MIC ALC MUT

37、ETONE/DCSDTMF 1750Hz Fig. 5 Modulation circuit Q644 RF AMP Q7 LOCAL AMP Q131 DRIVE AMP IC131 VHF Power AMP VCO A LPF Q161 RF AMP Q72 LOCAL AMP Q162 DRIVE AMP IC161 UHF Power AMP VCO B LPFHPF ANT Fig. 6 Transmitter circuit 3-3. APC Circuit The Automatic transmission Power Control (APC) circuit has a

38、differential amplifier (IC187) that compares the DC voltage generated by detecting part of the transmission output using diodes (D191, D192) with the reference voltage output from the D/A IC (IC667). The output signal is switched by IC186 and is fed to the power module of each VHF/UHF to keep transm

39、ission output constant. Fig. 7 APC circuit IC131 VHF Power AMP LPF IC161 UHF Power AMP LPFHPF ANT Reverse Forward D192 D191 OP AMP IC187 Analog SW IC186 APC V APC U D/A IC667 REV REFFWR REF VSF to MPU CIRCUIT DESCRIPTION TM-V71A/V71E 7 3-4. Overheating Protection Circuit To protect thermal destructi

40、on of the power modules (IC131, IC161), the voltage of the thermistors (TH131, TH161) near the power modules (IC131, IC161) is monitored by the MPU (IC918). If their temperature becomes high, this circuit reduces the APC voltage to cool down the temperature. 4. PLL Circuit 4-1. Reference Oscillator

41、Circuit Band A divides 12.8MHz inside the PLL IC (IC1) or band B divides 16.8MHz inside the PLL IC (IC66) to generate a 5kHz or 6.25kHz reference frequency. The 16.8MHz signal on IC66 side is tripled by Q547 to obtain the second local oscillator for band B. The reference oscillation circuit is also

42、modulated to improve the modulation characteristics of the DCS and 9600bps packet signal when it is transmitted. 4-2. Phase Comparator Part of the band A VCO output is amplifi ed by Q5 and goes to PLL IC (IC1). Also, a part of the band B VCO output is amplified by Q70 and goes to the PLL IC (IC66).

43、The pulse-swallow type PLL IC divides the input VCO oscillator frequency using the data from the MPU (IC918). It compares its phase with that of the reference frequency to make the PLL synthesizer to generate the desired step. 4-3. Lock Voltage (VCO Control Voltage) The phase differential comparator

44、, output from the PLL IC, results in a phase difference pulse. As for the result of phase comparison with the PLL IC, a phase difference is output as a pulse. This pulse is amplifi ed by a charge pump (Q2, Q3 or Q67, Q68) and the ripples are removed by a low-pass fi lter, then the signal is supplied

45、 as the oscillator frequency control voltage for each VCO. 4-4. Unlock Detection Circuit When the PLL is unlocked, a low state voltage is output from the LD terminal (pin 8) of the PLL IC. This signal is monitored by the MPU (IC918) to control transmission/ reception switching timing. Fig. 8 PLL cir

46、cuit 12.8MHz TCXO LPFLPF PLL IC IC1 VCO A Q2 Q3 Q7 Q5 TCXO A Mod Signal X1 LOCAL VCO A Mod Signal Charge PumpBand A 16.8MHz TCXO LPFLPF PLL IC IC66 Tripler x3 VCO B Q67 Q68 Q72 Q70 TCXO B Mod Signal X66 LOCAL VCO B Mod Signal Charge PumpBand B Q547 5. Power Supply Circuit 5-1. Microcomputers and Per

47、ipheral Circuits Reset and Backup Circuits The MPU reset signal detects a rising edge of the M5 line voltage with the reset IC (IC920). When the voltage supplied to the transceiver decreases and the B line voltage falls below the detection voltage of the voltage detection IC (IC919), the MPU (IC918)

48、 detects it through the interrupt terminal, stores the data in the EEPROM (IC916), and shuts the power off. 5-2. Voltage Detection Processing The MPU (IC918) monitors and process various voltage statuses at A/D ports of IC918. The squelch voltage is input from the FM IC and a change in the noise voltage is detected to con