Kenwood NX-740H(V) Service Manual
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Kenwood NX-740H(V) Service Manual

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B5B-7207-00
RA028<Rev.001>
6 S ERVICE MANUAL
2015
NX-740H, NX-740H(V), NX-740
COPYRIGHT © 2015 JVC KENWOOD Corporation
1
PRECAUTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
2
SPECIFIC SERVICE INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
3
DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-21
4
ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-23
5
TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-30
This service manual is applied for Hardware Ver 2.0 transceivers (K, M types)
with B56xxxxx or subsequent serial numbers.
This product complies with the RoHS directive for the European market.
B5B-7207-00
SERVICE MANUAL
VHF DIGITAL TRANSCEIVER
COPYRIGHT © 2015 JVC KENWOOD Corporation

TABLE OF CONTENTS

ACC.
This product uses Lead Free solder.
No.RA028<Rev.001>
2015/6

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  • Page 1: Table Of Contents

    NX-740H, NX-740H(V), NX-740 ACC. COPYRIGHT © 2015 JVC KENWOOD Corporation TABLE OF CONTENTS PRECAUTION............... . . 1-4 SPECIFIC SERVICE INSTRUCTIONS .
  • Page 2 Neither is any liability assumed for damages resulting from the use of the information contained herein. JVC KENWOOD Corporation reserves the right to make changes to any products herein at any time for improvement purposes. Firmware Copyrights The title to and ownership of copyrights for firmware embedded in KENWOOD product memories are reserved for JVC KENWOOD Corporation.
  • Page 3 16K0F3E, 11K0F3E, 4K00F1E, 4K00F1D, 4K00F7W, 4K00F2D, 8K30F1E, 8K30F1D, 8K30F7W Analog measurements made per TIA/EIA-603 and specifications shown are typical. Digital measurements made per NXDN CAI and specifications shown are typical. JVC KENWOOD Corporation reserves the right to change specifications without prior notice or obligation. (No.RA028<Rev.001>)1-3...

  • Page 4: Precaution

    SECTION 1 PRECAUTION This service manual does not describe PRECAUTION. SECTION 2 SPECIFIC SERVICE INSTRUCTIONS SYSTEM SET-UP Merchandise received Type RF power Frequency range (MHz) 136~174 NX-740 M Choose the type of transceiver 136~174 NX-740H K 136~174 NX-740H(V) K A personal computer, programming interface (KPG-46A/46U), Transceiver programming and FPU (programming software) are required for programming.
  • Page 5 The KPG-46U driver runs under Win- dows XP, Vista, 7, 8 or 8.1. The latest version of the USB driver is available for download from the following URL: http://www.kenwood.com/usb-com/ (This URL may change without notice.) (No.RA028<Rev.001>)1-5...
  • Page 6 2.2.4.2 Flow chart (Source transceiver) D-sub 15-pin Pin No. Name Molex 15-pin Pin No. Press [ ] key + Power ON for 2 seconds FNC1 FNC2 password* set? FNC3 * Read Authorization Shows PS FNC4 password FNC5 Enter password FNC6 Is entered password correct?
  • Page 7 2.3.3 Ignition Sense Cable (KCT-18: Option) Installation Procedure: Method B The KCT-18 is an optional cable for enabling the ignition func- (1) Remove the ACC. cap on the rear of the transceiver. tion. The ignition function lets you turn the transceiver power on (2) Connect the D-sub connector of the KCT-60 to the D-sub and off with the car ignition key.
  • Page 8 2.3.4.2 KES-5 2.3.6 Extended Function: COM Port 0 and COM Port 1 External speaker KES-5 can be installed for KCT-60. Location of COM Port 0 and COM Port 1 of the transceiver is shown below. Connection procedure (1) Remove the ACC. cap on the rear of the transceiver. COM Port 1 (2) Connect the D-sub connector of the KCT-60 to the D-sub 15-pin terminal of the transceiver.
  • Page 9 2.3.8 Changing of Signal Type (3) Dress the cable as shown in the figure. The cable needs to pass through one of two indentations located on the rear 2.3.8.1 Change signal input of D-SUB connector from DI to panel of the transceiver. The input (5pin) of D-SUB 15-pin connector is configured at the DI as the default value.
  • Page 10 CIRCUIT DESCRIPTION 2.4.1 Frequency Configuration The receiver utilizes double conversion. The first IF is 49.95MHz and the second IF is 450kHz. The first local oscillator signal is sup- plied from the PLL circuit. The PLL circuit in the transmitter generates the necessary frequencies. Figure 1 shows the frequencies. 49.95MHz IF SYSTEM 50.4MHz...
  • Page 11 2.4.2.4 AF Signal System The detection signal from FM IC (IC501) goes to the baseband IC (IC709) DISC input (pin 16) after pass through IC500 for character- izing the signal. • Analog signal The demodulated AF signal pass through IC709 with the signal processing and output at AUDIO (pin26) to the E-Vol before the Audio amplifier (IC719).
  • Page 12 2.4.3.3 APC Circuit The automatic transmission power control (APC) circuit detects part of a final amplifier output with a coupler circuit and applies a volt- age to IC301. IC301 compares the APC control voltage (APCC) generated by the baseband IC (IC709) and DC amplifier (IC503) with the detection output voltage.
  • Page 13 2.4.5 Control Circuit The MCU carries out the following tasks: (1) Controls the FM IC (IC501). (2) Controls the baseband IC (IC709). (3) Controls the PLL (IC2) & TX/RX outputs. (4) Controls IO expender through I2C level converter. (5) Controls the display unit. PLL IC C.DATA RSTN...
  • Page 14 2.4.5.3 Key Matrix Circuit < The front panel has function keys. Each of them is connected to KMO1 a cross point of a matrix of the KMI1 to KMO3 ports of the micro- CH UP processor. > KMO2 The KMO1 to KMO3 ports are always high, while the KMI1 to IC714 KMI3 ports are always low.
  • Page 15 2.4.6.3 NXDN Receiving • For Digital Data Mode: The demodulated signal from IC501 (Pin13) feed into baseband IC (Pin 16) for NXDN decoding. The decoded digital data will pass to MCU through C-BUS. MCU determines whether or not to output sound from speaker by check- ing if the data match.
  • Page 16 2.4.7 Power Supply Circuit • When the power switch on the display unit is pressed, the power port on the display unit which is connected pin 140 (POWKEY), goes low, then pin88 (SBC) goes high, Q718 turns on, SB SW (Q719) turns on and power (SB) is supplied to the transceiver. •...
  • Page 17 Port Name Function Port Name Function - 33MD - 33MD LSDO O Low-Speed Data Output MKEYI I DTMF MIC key input HSDO O High-Speed Data Output BUCNT2 O DTMF MIC buffer control O 33C Control PLL_UL I PLL Unlock Detect O 5C Control O SB Control SQIN...
  • Page 18 Port Name Function Ref. No. Part Name Description IC701 3.3V level shifter 129 NC O No connection (RXDO/CTSO) 130 VSS - GND IC702 IO expander 131 VDD - 33MD IC703 5V level shifter (TXDO/RTSO) 132 NC O No connection IC704 RS-232C driver 133 SWO O SWO for SWD...
  • Page 19 Ref. No. Part Name Description Ref. No. Part Name Description Q705 MOD2 switch D309, Diode ANT switch D310 Q706 Transistor Ignition sense control switch D500 Diode Squelch voltage rectifier Q707 Transistor 9R control switch D502~ Variable RF BPF tuning Q708 Transistor 9T control switch D505...
  • Page 20 Name Function Name Function 25 SP- Speaker input - 25 MIC MIC signal input 26 SP- Speaker input - 26 ME MIC ground 27 SP+ Speaker input + 27 HOOK/RXD I/O HOOK/PC serial data 28 SP+ Speaker input + 28 PTT/TXD I/O PTT/PC serial data 29 SB Battery voltage DC supply...

  • Page 21: Disassembly

    SECTION 3 DISASSEMBLY Disassembly Procedure (4) To remove the speaker holder, first remove the two screws from the display PCB using a phillips screwdriver. (1) When removing the cabinet, first remove the two screws Then, insert a flat-head screwdriver under the tabs of the from the right and left with a phillips screwdriver.
  • Page 22 Note: (2) When mounting the panel assembly, pass the flat cable When you supply power to the TX-RX PCB after remov- through the hole of the chassis as shown below then con- ing the TX-RX PCB from the chassis, solder the positive nect the flat cable to connector of the panel assembly.

  • Page 23: Adjustment

    SECTION 4 ADJUSTMENT Test Equipment Required for Alignment Test Equipment Major Specifications 1. Standard Signal Generator Frequency Range 100 to 520MHz (SSG) Modulation Frequency modulation and external modulation Output -127dBm/0.1μV to greater than -7dBm/100mV 2. Power Meter Input Impedance 50Ω Operation Frequency 100 to 520MHz Measuring Range...
  • Page 24 Frequency and Signaling Preparations for Tuning the Transceiver The transceiver has been adjusted for the frequencies shown in Before attempting to tune the transceiver, connect the unit to a the following table. When required, re-adjust them following the suitable power supply. adjustment procedure to obtain the frequencies you want in ac- Whenever the transmitter is tuned, the unit must be connected to tual operation.
  • Page 25 Common Section Item Condition Measurement Adjustment Specifications /Remarks Test- Unit Terminal Unit Parts Method equipment 1. Setting 1) Power supply voltage DC power supply terminal : 13.6V 2. Receive 1) Select each tab FPU Voltage level indi- 2.5 ±0.1V Assist voltage CH : Low cated in PC window CH : Low'...
  • Page 26 Item Condition Measurement Adjustment Specifications /Remarks Test- Unit Terminal Unit Parts Method equipment 4. Low 1) Test CH : Low, Low', Power meter FPU 5.0W ±0.5W Transmit Center, High', High Ammeter 4.0A or less Power ( 5 point ) 2) Battery Terminal voltage : 13.6V 3) PTT ON ( Transmit ) 5.
  • Page 27 Item Condition Measurement Adjustment Specifications /Remarks Test- Unit Terminal Unit Parts Method equipment 9. DQT 1) Test CH : Center ( 1 point ) Deviation FPU 0.35kHz ±50Hz Deviation 2) Deviation meter filter Meter (Analog LPF : 3kHz Oscilloscope Narrow) HPF : OFF 3) PTT ON ( Transmit ) (Analog Wide) 1) Test CH : Center ( 1 point )
  • Page 28 Receiver Section Item Condition Measurement Adjustment Specifica- tions Test- Unit Terminal Unit Parts Method /Remarks equipment 1. Receive 1) Test CH : Low, Low', Center, FPU Press [Start], [Auto Sensitivity High', High ( 5 point ) Oscilloscope tuning] [Semiauto- 2) SSG output : -90dBm Audio matic] AF Freq : 1kHz...
  • Page 29 Item Condition Measurement Adjustment Specifica- tions Test- Unit Terminal Unit Parts Method /Remarks equipment 4. Low RSSI [Analog Narrow] FPU Press [Start], [Auto 1) Test CH : Low, Low', Center, Oscilloscope tuning] High', High ( 5 point ) Audio 2) SSG output : -120dBm Analyzer AF Freq : 1kHz Mod Dev : ±1.5kHz...

  • Page 30: Troubleshooting

    KPG-175D. "Service TX-RX unit" Data Note: The following data is written on the service TX-RX unit: • When a new printed circuit board is used, the KENWOOD ESN changes, as does the Transceiver Information dis- Data Type Description...
  • Page 31 SCHEMATIC DIAGRAM TX-RX UNIT (XC1-0010-10 (NX-740H(K), NX-740H(V)(K)), XC1-0010-21 (NX-740(M))) RX VCO R:5.27V R:1.71V (86) 4.7u DRIVE AMP 100p (14) 1SV325F R980 R983 R994 100n 3.22V T:8.92V VHF(HK) R:0V (-92) 0-10 0.01u CV(A) (-92) 136-174M 2.63V T:3.37V T:2.42V L303 (Ver2) L305 C313 VHF(M) 0.01u...
  • Page 32 MEMO (No.RA028<Rev.001>) 2-2...
  • Page 33 DISPLAY UNIT (X54-3890-20) KEY BACKLIT HOOK 4.06V 13.53V KRA225S 5.6k B30-2337-05 B30-2337-05 4.06V 5.6k B30-2337-05 B30-2337-05 1.90V KRC102S-P 6.8k HDSP-521A B30-2337-05 4.94V LEDM RLED GLED BLED KMO1 KMO2 KMO3 TO TX-RX 2SC3928A KMI1 UNIT KMI2 CN700 KMI3 RK74HB1J102J L92-0138-05 LEDI LECE LECL LELH...

  • Page 34: Printed Circuit Board

    PRINTED CIRCUIT BOARD TX-RX UNIT (XC1-0010-10 (NX-740H(K), NX-740H(V)(K)), XC1-0010-21 (NX-740(M))) --- Component side view (J7C-0002-40) --- J701 C958 D-SUB C962 J700 R769 R752 R755 C956 R770 C941 F700 CN713 CN703 CN709 CN704 CN710 CN705 C605 R772 C606 C949 C729 C727 C725 C723 C721 C720...
  • Page 35 TX-RX UNIT (XC1-0010-10 (NX-740H(K), NX-740H(V)(K)), XC1-0010-21 (NX-740(M))) --- Foil side view (J7C-0002-40) --- D715 R789 Q703 R786 C745 R356 D714 R741 C947 Q702 C950 C364 C952 C955 C609 C769 C773 C361 C360 C772 C774 C771 C770 C994 TH302 R774 C775 L313 D719 C357...
  • Page 36 A-1C ADDRESS TABLE OF BOARD PARTS Side Y axis Each address may have an address error by one X axis interval. REF.NO. LOCATION REF.NO. LOCATION REF.NO. LOCATION REF.NO. LOCATION REF.NO. LOCATION REF.NO. LOCATION REF.NO. LOCATION REF.NO. LOCATION REF.NO. LOCATION REF.NO. LOCATION REF.NO. LOCATION REF.NO. LOCATION REF.NO. LOCATION REF.NO. LOCATION REF.NO. LOCATION B- 3A B- 4B R503...
  • Page 37 DISPLAY UNIT (X54-3890-20) --- Component side view (J79-0249-39) --- ADDRESS TABLE OF BOARD PARTS POWER Each address may have an address error by one interval. A-1C Side Y axis X axis REF.NO. LOCATION REF.NO. LOCATION REF.NO. LOCATION REF.NO. LOCATION RESISTOR B- 1B B- 1A B- 4B...
  • Page 38 LEVEL DIAGRAM Receiver Section RF (Center Frequency) IF_1 (49.95MHz) IF_2 (450kHz) AF Frequency (1kHz) 228mVrms N: -114dBm 73mVrms 72mVrms 71mVrms N: -97dBm 0.091Vrms N: -120.5dBm N: - 98.5dBm N: -96.5dBm N: - 118dBm 246mVrms 4 Vrms 4.51 Vrms IF amplifier Baseband IC FMIC Baseband IC...

  • Page 39: Block Diagram

    BLOCK DIAGRAM DISPLAY UNIT X54-389 TX/RX UNIT XC1-001 IC300 D305,306 : L407CDB Q300 POWER 9T 9R 2SC5636 MCH3914(7)-H 2SC5108(Y)F 2SC5108(Y)F RD00HVS1-T113 RA60H1317M1A 136-174MHz D309,D310 : COUPPLER TX/RX POWER DRIVE BUFF POWER MODULE KMO1 AK1541 PLL_LE LV/C KRX102U D16,17 <B LOOP PLL_CLK RN142S Filter...
  • Page 40 MEMO...

  • Page 41: Parts List

    PARTS LIST [NX-740H,NX-740H(V),NX-740] * SAFETY PRECAUTION Parts identified by the symbol are critical for safety. Replace only with specified part numbers. * BEWARE OF BOGUS PARTS Parts that do not meet specifications may cause trouble in regard to safety and performance.
  • Page 42 Exploded view of general assembly and parts list Block No.M1MM J701 J700 IC719 IC300 R356 TX-RX UNIT<02> DISPLAY UNIT<01> 3-2(No.RA028<Rev.001>)
  • Page 43 General assembly Block No. [M][1][M][M]  Symbol No. Part No. Part Name Description Local A02-4073-31 PLASTIC CABINET A6A-0004-00 PANEL ASSEMBLY B09-0732-03 CAP(D-SUB) B4D-0003-00 BADGE B10-2794-03 FRONT GLASS E04-0167-15 RF COAXIAL RECEPTACLE(M) E23-1346-04 GROUND TERMINAL E30-7684-25 DC CORD E37-1461-05 FLAT CABLE(30P PANEL) G53-1643-04 PACKING(DC CORD) G53-1662-04...

  • Page 44: Electrical Parts List

    Electrical parts list DISPLAY UNIT  Symbol No. Part No. Part Name Description Local X54-3890-20 RK73HB1J100J MG RESISTOR 10 J 1/16W Block No. [0][1] RK73HB1J150J MG RESISTOR 15 J 1/16W RK73HB1J100J MG RESISTOR 10 J 1/16W  Symbol No. Part No. Part Name Description Local...
  • Page 45  Symbol No. Part No. Part Name Description Local  Symbol No. Part No. Part Name Description Local Q502 2SC2412K TRANSISTOR Q503 3SK318 CK73HBB1H102K C CAPACITOR 1000PF K Q504 KTC4075E(Y,GR) TRANSISTOR CK73HBB1H102K C CAPACITOR 1000PF K Q505 LTC014EEBFS8 DIGI TRANSISTOR CC73HCH1H101J C CAPACITOR 100PF J Q506...
  • Page 46  Symbol No. Part No. Part Name Description Local  Symbol No. Part No. Part Name Description Local C108 CC73GCH1H180J C CAPACITOR 18PF J C518 CK73HB1A333K C CAPACITOR 0.033UF K C300 CK73HBB1H102K C CAPACITOR 1000PF K C519 CC73HCH1H820J C CAPACITOR 82PF J C301 CC73GCH1H151J C CAPACITOR...
  • Page 47  Symbol No. Part No. Part Name Description Local  Symbol No. Part No. Part Name Description Local C703 CK73HB1H103K C CAPACITOR 0.010UF K C803 CC73HCH1H101J C CAPACITOR 100PF J C704 CK73HBB1H471K C CAPACITOR 470PF K C806 CK73HB0J475M C CAPACITOR 4.7UF M C705 CK73HBB1H102K C CAPACITOR...
  • Page 48  Symbol No. Part No. Part Name Description Local  Symbol No. Part No. Part Name Description Local C919 CK73GBB1H102K C CAPACITOR 1000PF K RK73HB1J103J MG RESISTOR 10K J 1/16W C920 CK73HXR0J105K C CAPACITOR 1.0UF K RK73HB1J100J MG RESISTOR 10 J 1/16W C921 CK73HBB1H102K C CAPACITOR 1000PF K...
  • Page 49  Symbol No. Part No. Part Name Description Local  Symbol No. Part No. Part Name Description Local R346 RK73RB2H101J MG RESISTOR 100 J 1/2W R577 RK73HB1J104J MG RESISTOR 100K J 1/16W R348 RK73GB2A102J MG RESISTOR 1.0K J 1/10W R578 RK73HB1J683J MG RESISTOR 68K J 1/16W...
  • Page 50  Symbol No. Part No. Part Name Description Local  Symbol No. Part No. Part Name Description Local R770 RK73HB1J101J MG RESISTOR 100 J 1/16W R880 RK73HB1J000J MG RESISTOR 0.0 J 1/16W R771 RK73HB1J000J MG RESISTOR 0.0 J 1/16W R881 RK73HB1J000J MG RESISTOR 0.0 J 1/16W...
  • Page 51  Symbol No. Part No. Part Name Description Local  Symbol No. Part No. Part Name Description Local R969 RK73HB1J474J MG RESISTOR 470K J 1/16W L510 LK73G0AF22NJ M.CHIP INDUCTOR 22NH R970 RK73HB1J564J MG RESISTOR 560K J 1/16W L512 L41-5678-14 M.CHIP INDUCTOR 56NH R971 RK73HB1J000J MG RESISTOR...
  • Page 52 Packing materials and accessories parts list Block No.M2MM Packing and accessories Block No. [M][2][M][M]  Symbol No. Part No. Part Name Description Local B5A-0031-20 INSTRUCTION MANUAL H_K,HV_K B5A-0030-10 INSTRUCTION MANUAL B5A-0747-00 INSTRUCTION MANUAL E30-7523-65 DC CORD ASSEMBLY F52-0024-05 FUSE(BLADE TYPE) 15A(x2) H_K,HV_K F52-0023-05...
  • Page 53 MEMO...
  • Page 54 JVC KENWOOD Corporation Communications Systems Business Operation (No.RA028<Rev.001>) Printed in Japan...

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Nx-740Nx-740h

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