Kenwood NX-420 K Service Manual
  1. Manuals
  2. Brands
  3. Kenwood Manuals
  4. Portable Radio
  5. NX-420 K
  6. Service manual

Kenwood NX-420 K Service Manual

800mhz digital transceiver
Hide thumbs
Table of Contents

Advertisement

Quick Links

800MHz DIGITAL TRANSCEIVER
NX-420
SERVICE MANUAL
Whip antenna
(T90-1114-05)
Knob (PTT)
(K29-9500-03)
Button knob
(Side1/Side2/AUX)
(K29-9501-03)
This product complies with the
RoHS
NX-420 K
Knob (Selector)
(K29-9486-13)
Knob (Volume)
(K29-9485-13)
Plastic cabinet assy
(A02-4130-13)
directive for the European market.
© 2013-2 PRINTED IN JA PAN
B53-7050-00 ( Y ) 561
NX-420 K3
Whip antenna
(T90-1114-05)
Knob (Selector)
(K29-9486-13)
Knob (Volume)
(K29-9485-13)
Knob (PTT)
(K29-9500-03)
Button knob
Packing (16Key)
(Side1/Side2/AUX)
(G53-1865-11)
(K29-9501-03)
Plastic cabinet assy
(A02-4132-13)
This product uses Lead Free solder.

Advertisement

Table of Contents
loading

Related Manuals for Kenwood NX-420 K

Summary of Contents for Kenwood NX-420 K

  • Page 1 800MHz DIGITAL TRANSCEIVER NX-420 SERVICE MANUAL © 2013-2 PRINTED IN JA PAN B53-7050-00 ( Y ) 561 NX-420 K NX-420 K3 Whip antenna Whip antenna (T90-1114-05) (T90-1114-05) Knob (Selector) Knob (Selector) (K29-9486-13) (K29-9486-13) Knob (Volume) Knob (Volume) (K29-9485-13) (K29-9485-13) Knob (PTT)

  • Page 2: Table Of Contents

    TROUBLE SHOOTING ......30 SPECIFICATIONS ........79 Document Copyrights Firmware Copyrights Copyright 2013 by JVC KENWOOD Corporation. All rights The title to and ownership of copyrights for firmware reserved. embedded in KENWOOD product memories are reserved No part of this manual may be reproduced, translated, for JVC KENWOOD Corporation.

  • Page 3: General

    NX-420 GENERAL INTRODUCTION PERSONAL SAFETY SCOPE OF THIS MANUAL The following precautions are recommended for personal safety: This manual is intended for use by experienced techni- • DO NOT transmit until all RF connectors are verifi ed se- cians familiar with similar types of commercial grade com- cure and any open connectors are properly terminated.

  • Page 4: System Set-Up

    SYSTEM SET-UP Merchandise received Type Frequency range (MHz) RF power LCD 16-key Choose the type of transceiver TX 806~825MHz NX-420 K TX/RX 851~870MHz TX 806~825MHz NX-420 K3 TX/RX 851~870MHz A personal computer, programming interface (KPG-22A/22U) are required for programming. Transceiver programming (The frequency, and signaling data are programmed for the transceiver.)

  • Page 5: Realignment

    NX-420 REALIGNMENT 1. Modes 5. PC Mode 5-1. Preface User mode The transceiver is programmed by using a personal com- puter, programming interface (KPG-22A/22U) and program- Panel test mode *1 Panel tuning mode *1 ming software (KPG-141D). The programming software can be used with a PC. Fig- PC mode Data programming mode ure 1 shows the setup of a PC for programming.
  • Page 6 • Normally, write in the high-speed mode. load from the following URL: • The text message are displayed for K3 model only. http://www.kenwood.com/usb-com/ (This URL may change without notice.) 7. Clone Mode (K3 model only) 5-5. Programming softwares KPG-141D (ver.3.10...
  • Page 7 NX-420 REALIGNMENT 2. When you enter the correct password, and “CLONE” is 7. The other target can be continuously cloned. When the displayed, the transceiver can be used as the cloning [ ] key on the source is pressed while the source displays source.

  • Page 8: Disassembly For Repair

    NX-420 DISASSEMBLY FOR REPAIR Removing the mechanical stopper (K3 model only) 1. Precautions for Disassembly 1. Pick up and lift the tab of a mechanical stopper using a ■ Removing the selector knob and volume knob pair of tweezers. a 1.
  • Page 9 NX-420 DISASSEMBLY FOR REPAIR Removing the speaker holder 2. Precautions for Reassembly There is a space of approximately 1mm (0.04 inch) be- Mounting the chassis onto the case tween the center part of the front glass of the speaker 1. Place the key top on the chassis. Then, fit the chassis holder and the surface of the Display unit.
  • Page 10 NX-420 DISASSEMBLY FOR REPAIR ■ Changing the channel selector from 16-channel Note: Refer to page 8 for how to install the channel selec- tor knob and knob spring. operation to free (without LCD models only) 1. Remove the channel selector knob a . (Refer to page 8 for how to remove the channel selector knob.) 2.
  • Page 11 NX-420 DISASSEMBLY FOR REPAIR ■ Assembly information (Sheet/Cushion) When “Main Parts” is changed (ordered), “Assembled Sheet/Cushion” should also be changed (ordered) together. The Sticker and Sheet etc are non-reusable parts. It requires the new one to get the radio’s performance after repairs. For example, when “Plastic Cabinet Assy (A02-4130-13 (without key)/A02-4132-13 (16-key))”...

  • Page 12: Circuit Description

    NX-420 CIRCUIT DESCRIPTION 1. Overview 2. Frequency Confi guration The NX-420 is a 800MHz portable transceiver designed to The receiver is a double-conversion superheterodyne us- operate in the frequency range of 806 to 870MHz. The unit ing the fi rst intermediate frequency (IF) of 49.95MHz and the consists of a receiver, transmitter, phase-locked loop (PLL) second IF of 450kHz.
  • Page 13 NX-420 CIRCUIT DESCRIPTION 3-2. IF circuit 3-3. Audio amplifi er circuit The first IF signal is passed through a four-pole mono- Audio processing (high-pass filter, low-pass filter, de- lithic crystal fi lter (XF300) to reject adjacent channel signals. emphasized and so on) at FM mode and decoding at NXDN The fi...
  • Page 14 NX-420 CIRCUIT DESCRIPTION 4-3. VOX 4-5. APC circuit The DSP detects the audio level. If the detected level be- The APC circuit always monitors the current flowing comes higher than the threshold level, the VOX starts. through the RF power amplifier (Q106) and keeps a con- stant current.
  • Page 15 NX-420 CIRCUIT DESCRIPTION When the frequency is controlled by the PLL, the frequen- 5-4. Local Switch (D411, D412) cy convergence time increases as the frequency difference The connection destination of the signal output from the increases when the set frequency is changed. To supple- buffer amplifier (Q408) is changed with the diode switch ment this, the ASIC is used before control by the PLL IC (D412) that is controlled by the transmission power supply,...
  • Page 16 NX-420 CIRCUIT DESCRIPTION 6-3. LCD 7. Power Supply Circuit The LCD is controlled using the 4 serial line from ASIC The battery voltage (+B) is provided from the battery ter- (IC607). minal on the TX-RX unit (X57). The battery voltage passes through the 2.5A fuse (F500), and goes to the RF fi...
  • Page 17 NX-420 CIRCUIT DESCRIPTION TX-RX unit F500 Final AMP, APC 2.5A F900 Q902 AFPA 1.0A IC900 2-pin Jack VOL/SW /PSW /BINT IC506 5.6V Det IC505 IC500 ASIC IC607 IC501 IC502 DSP, FLASH, SRAM IC503 PLL, TCXO IC504 ASSIST circuit Q504 TX circuit Q505 RX circuit Q500...

  • Page 18: Components Description

    NX-420 COMPONENTS DESCRIPTION Display unit (X54-3760-12) K type TX-RX unit (X57-8370-10) Ref No. Part Name Description Ref. No. Part Name Description IC100 APC control ASQ BPF/ASQ BPF IC200 1st mixer OP AMP(AF LPF/MIC AMP) IC300 Buffer amplifi re (DET) D/A converter IC301 FM system OP AMP(VCO_MOD/VREF)
  • Page 19 NX-420 COMPONENTS DESCRIPTION Ref No. Part Name Description Q403 Transistor Ripple Filter Q404 Switch control (Q406) Q405 Transistor Doubler Q406 DC switch (VCO) Q407 Transistor Buffer amplifi re Q408 Transistor RF amplifi re Q500 DC switch (SB2) Q501 Switch control (Q500) Q502 Transistor Switch control (Q504)

  • Page 20: Parts List

    NX-420 PARTS LIST New Parts. indicates safety critical components. L : Scandinavia K : USA P : Canada Parts without Parts No. are not supplied. Y : PX (Far East, Hawaii) T : England E : Eu rope Les articles non mentionnes dans le Parts No. ne sont pas fournis. C : China X : Australia M : Oth er Areas...
  • Page 21 NX-420 PARTS LIST DISPLAY UNIT (X54-3760-XX) TX-RX UNIT (X57-8370-10) Desti- Desti- Ref. No. Ad dress Parts No. Description Ref. No. Ad dress Parts No. Description parts nation parts nation C42 -44 CC73HCH1H470J CHIP C 47PF RK73HB1J683J CHIP R 1/16W CK73HB1H102K CHIP C 1000PF R28 -30...
  • Page 22 NX-420 PARTS LIST TX-RX UNIT (X57-8370-10) Desti- Desti- Ref. No. Ad dress Parts No. Description Ref. No. Ad dress Parts No. Description parts nation parts nation C113 CC73HCH1H100B CHIP C 10PF C221 CC73HCH1H030B CHIP C 3.0PF C114-119 CC73HCH1H101J CHIP C 100PF C222 CC73HCH1H101J...
  • Page 23 NX-420 PARTS LIST TX-RX UNIT (X57-8370-10) Desti- Desti- Ref. No. Ad dress Parts No. Description Ref. No. Ad dress Parts No. Description parts nation parts nation C425 CK73HB1A104K CHIP C 0.10UF C512 CK73HB1A104K CHIP C 0.10UF C426-429 CC73HCH1H101J CHIP C 100PF C513,514 CC73HCH1H101J...
  • Page 24 NX-420 PARTS LIST TX-RX UNIT (X57-8370-10) Desti- Desti- Ref. No. Ad dress Parts No. Description Ref. No. Ad dress Parts No. Description parts nation parts nation C661 CK73HB1A104K CHIP C 0.10UF L109 L92-0408-05 CHIP FERRITE C663 CK73GB0J106K CHIP C 10UF L112 L34-4550-05 AIR-CORE COIL(7.5T)
  • Page 25 NX-420 PARTS LIST TX-RX UNIT (X57-8370-10) Desti- Desti- Ref. No. Ad dress Parts No. Description Ref. No. Ad dress Parts No. Description parts nation parts nation L605-607 L92-0444-05 CHIP FERRITE R150 RK73HB1J000J CHIP R 1/16W L608 L92-0162-05 BEADS CORE R151 RK73HB1J271J CHIP R 1/16W...
  • Page 26 NX-420 PARTS LIST TX-RX UNIT (X57-8370-10) Desti- Desti- Ref. No. Ad dress Parts No. Description Ref. No. Ad dress Parts No. Description parts nation parts nation R410 RK73HB1J473J CHIP R 1/16W R514 RK73HB1J471J CHIP R 1/16W R411 RK73HB1J470J CHIP R 1/16W R515 RK73GB2A000J...
  • Page 27 NX-420 PARTS LIST TX-RX UNIT (X57-8370-10) Desti- Desti- Ref. No. Ad dress Parts No. Description Ref. No. Ad dress Parts No. Description parts nation parts nation R904 RK73HB1J473J CHIP R 1/16W Q101 2SC5636 TRANSISTOR R905 RK73GB2A104J CHIP R 100K 1/10W Q102 2SK3077F R906...

  • Page 28: Exploded View

    NX-420 EXPLODED VIEW 16 (K) 3 (K3) MIC1 (C/3) Display unit (A54-376 A/3) Fx14 TX-RX unit (X57-837) S101 X54 (B/3) A : M2.6X4 : N09-2438-05 B : M2.6X10 : N09-6608-05 46x2 : N14-0864-04 : N14-0865-04 E : M3X6 : N30-3006-43 F : M2X5 : N83-2005-48 Parts with the exploded numbers larger than 700 are not supplied.

  • Page 29: Packing

    NX-420 PACKING 54 Belt clip (J29-0701-25) 7 Cap (B09-0686-03) 16 Stopper (16CH) (D32-0454-04) 51 Holder (J19-5483-23) 48 Packing fixture (H12-4312-02) 708 Pamphlet 13 Instruction manual 66 Whip antenna (B62-2470-00) (T90-1114-05) 48 Item carton case (H52-2594-02) Parts with the exploded numbers larger than 700 are not supplied.

  • Page 30: Trouble Shooting

    NX-420 TROUBLE SHOOTING Fault Diagnosis of the BGA (Ball Grid Array) IC ■ Overview A fl owchart for determining whether or not the transceiver can be powered on (the LCD does not function even if the power switch is turned on) due to broken BGA parts. ■...
  • Page 31 NX-420 TROUBLE SHOOTING The LCD displays control *1 When an abnormal value is confirmed. Points to be checked Normal voltage If the /LCDCS is 0V or 3.3V, the ASIC/FLASH/SRAM /LCDCS R640 3.3V→0V→3.3V may be broken. When a normal value is confirmed. The LCD does not function even if it is exchanged with the Display unit.
  • Page 32 System cannot be accessed. Maintain the ESN data of the Trunking System following the new ESN. NXDN ESN Label • When a new printed circuit board is used, the KENWOOD MPT ESN Label ESN changes, as does the Transceiver Information display...

  • Page 33: Adjustment

    NX-420 ADJUSTMENT Controls “ ” not appears on the LCD display Power switch/ Function Display Selector Volume Use as the DTMF keypad. [0] to [9] If a key is pressed during transmission, the DTMF [#], [ ] corresponding to the key that was presses is sent.
  • Page 34 NX-420 ADJUSTMENT ■ Frequency and Signaling Panel Tuning Mode (K3 model only) The transceiver has been adjusted for the frequencies ■ Transceiver tuning (To enter tuning mode) shown in the following table. When required, readjust them To enter tuning mode, press the [ ] key while the trans- following the adjustment procedure to obtain the frequencies ceiver is in test mode.
  • Page 35 NX-420 ADJUSTMENT ■ 2 reference level adjustments frequency ■ 3 reference level adjustments frequency Receive Assist Tuning point RX (MHz) TX (MHz) Tuning point RX (MHz) TX (MHz) 851.100000 806.000000 851.100000 806.000000 Center 859.900000 815.000000 High 869.900000 825.000000 High 869.900000 825.000000 QT Deviation DQT Deviation...
  • Page 36 NX-420 ADJUSTMENT Adjustment Item Description RSSI Reference The minimum RSSI level for scan stop is adjusted. Open Squelch The squelch level at level “ 5 ” is adjusted. RSSI display level “ ” is adjusted. Low RSSI Both “ Low RSSI ” and “High RSSI” must be adjusted. High RSSI (The curve data of RSSI level is applied.) Tight Squelch...
  • Page 37 NX-420 ADJUSTMENT AW (Analog AS (Analog AN (Analog NN (NXDN Nar- NV (NXDN Very Adjusutment Panel Adjust item Wide 5k) Wide 4k) Narrow) row) Narrow) Order item tuning test Number Adjustment range - *1 Receiver RSSI Reference Section 4 1~256 - *1 Receiver Open Squelch...
  • Page 38 NX-420 ADJUSTMENT [Side2] [Side2] [Side2] DQT Deviation DQT Deviation Wide DQT Deviation Wide Narrow ] press ] hold [Side2] [Side2] [Side2] Wide LTR Deviation LTR Deviation Wide LTR Deviation Narrow ] press ] hold [Side2] [Side2] [Side2] DTMF Deviation DTMF Deviation Wide DTMF Deviation Wide...
  • Page 39 ■ Nut wrench In order to turn the volume nut and the channel selector nut, use a recommendation tool. + Terminal (Red) KENWOOD part No.: W05-1123-00 – Terminal (Black) ■ Battery Jig (W05-0909-00) Connect the power cable properly between the battery...
  • Page 40 NX-420 ADJUSTMENT Radio Check Section Condition Measurement Adjustment Specifi cations / Item Test- Remarks Panel test mode PC test mode Unit Terminal Unit Parts Method equipment 1. Frequency 1) CH-Sig: 1-1 1) Test Channel f. counter Panel ANT Check an internal 806.04980~ check PTT: ON...
  • Page 41 NX-420 ADJUSTMENT Condition Measurement Adjustment Specifi cations / Item Test- Remarks Panel test mode PC test mode Unit Terminal Unit Parts Method equipment 5. Sensitivity 1) CH-Sig : 1-1 1) Test Channel Panel ANT Check 12dB SINAD or check SSG output Channel: 1 AF VM SP/MIC...
  • Page 42 NX-420 ADJUSTMENT Condition Measurement Adjustment Specifi cations / Item Test- Remarks Panel tuning mode PC test mode Unit Terminal Unit Parts Method equipment 4. Receive This adjustment can [Manual Adjustment] Panel [PC test [PC test mode] 2.5V±0.1V Assist be performed only in 1) Adj item: [Receive mode] [Automatic Adjustment]...
  • Page 43 NX-420 ADJUSTMENT Transmitter Section Condition Measurement Adjustment Specifi cations / Item Test- Remarks Panel tuning mode PC test mode Unit Terminal Unit Parts Method equipment 1. High power 1) Adj item: [HPWR] 1) Adj item: [High Power meter Panel ANT Panel [Panel 3.0W ±0.2W...
  • Page 44 NX-420 ADJUSTMENT Condition Measurement Adjustment Specifi cations / Item Test- Remarks Panel tuning mode PC test mode Unit Terminal Unit Parts Method equipment Maximum 1) Adj item: [NDEV] 1) Adj item: [Maximum Deviation Panel ANT Panel [Panel 1337Hz 1311~1363Hz Deviation Adjust: [ Deviation (NXDN meter...
  • Page 45 NX-420 ADJUSTMENT Condition Measurement Adjustment Specifi cations / Item Test- Remarks Panel tuning mode PC test mode Unit Terminal Unit Parts Method equipment Maximum 1) Adj item: [ADEV] 1) Adj item: [Maximum Deviation Panel ANT Panel [Panel 4200Hz 4150~4250Hz Deviation Adjust: [ Deviation (Analog meter...
  • Page 46 NX-420 ADJUSTMENT Condition Measurement Adjustment Specifi cations / Item Test- Remarks Panel tuning mode PC test mode Unit Terminal Unit Parts Method equipment 7. DQT 1) Adj item: [DQT] 1) Adj item: [DQT Devia- Deviation Panel ANT Panel [Panel Write the value as 0.35kHz±0.05kHz Deviation Adjust: [...
  • Page 47 NX-420 ADJUSTMENT Condition Measurement Adjustment Specifi cations / Item Test- Remarks Panel tuning mode PC test mode Unit Terminal Unit Parts Method equipment 9. DTMF 1) Adj item: [DTMF] 1) Adj item: [DTMF Deviation Panel ANT Panel [Panel Write the value as 1.25kHz±0.05kHz Deviation Adjust: [...
  • Page 48 NX-420 ADJUSTMENT Condition Measurement Adjustment Specifi cations / Item Test- Remarks Panel tuning mode PC test mode Unit Terminal Unit Parts Method equipment 1) Adj item: [MSK] 1) Adj item: [MSK Deviation Panel ANT Panel [Panel Write the value as 2.40kHz±0.05kHz Deviation Adjust: [...
  • Page 49 NX-420 ADJUSTMENT ■ Necessary Deviation adjustment item for each signaling and mode The following shows the necessary adjustment items for each signaling deviation. Please read the following table like the following example. In the case of the signaling “QT (Wide 5k)”, this signaling is composed of three elements [Balance, Maximum Deviation (Analog Wide 5k) and QT Deviation (Wide 5k)].
  • Page 50 NX-420 ADJUSTMENT Receiver Section Condition Measurement Adjustment Specifi cations / Item Test- Remarks Panel tuning mode PC test mode Unit Terminal Unit Parts Method equipment 1. AF level [Panel test mode] 1) Test Channel Panel ANT Panel Volume Turn the Volume 0.63V±0.1V setting 1) CH-Sig: 1-1...
  • Page 51 NX-420 ADJUSTMENT Condition Measurement Adjustment Specifi cations / Item Test- Remarks Panel tuning mode PC test mode Unit Terminal Unit Parts Method equipment 3. Open 1) Adj item: [SQL] 1) Adj item: [Open Panel ANT [Panel tuning mode] “Open Squelch” Squelch *6 Adjust: [ Squelch (Analog...
  • Page 52 NX-420 ADJUSTMENT Condition Measurement Adjustment Specifi cations / Item Test- Remarks Panel tuning mode PC test mode Unit Terminal Unit Parts Method equipment 4. Low 1) Adj item: [LRSS] 1) Adj item: [Low RSSI Panel ANT [Panel tuning mode] RSSI at Adjust: [ (Analog Narrow)] SP/MIC...
  • Page 53 NX-420 ADJUSTMENT Condition Measurement Adjustment Specifi cations / Item Test- Remarks Panel tuning mode PC test mode Unit Terminal Unit Parts Method equipment 5. High RSSI 1) Adj item: [HRSS] 1) Adj item: [High Panel ANT Panel tuning mode] at –80dBm Adjust: [ RSSI (Analog Wide SP/MIC...

  • Page 54: Terminal Function

    NX-420 TERMINAL FUNCTION Display unit (X54-3760-XX A/3) Pin No. Name Function Pin No. Name Function Volume level input for audio control VOL_GND GND for volume level 33M input ENC3 Rotary switch input SCK0 Clock input SDI0 Serial data input ENC4 Rotary switch input SDO0 Serial data output...
  • Page 55 NX-420 TERMINAL FUNCTION SP/MIC Connector Specifi cation Signal Description Item and Condition Unit Note Name Type Input Voltage (High) PTT/ PTT/RXD input Digital Zin=10k Input Voltage (Low) Maximum Input Voltage 1100 mVrms External MIC input AF=1kHz MICI Analog Zin=1.8k@1kHz Standard Input Voltage 12.5 18.3 mVrms...

  • Page 56: Pc Board

    NX-420 PC BOARD DISPLAY UNIT (X54-3760-XX) -10: K3 -12: K Component side view (J79-0312-09) J79-0312 -09 C/3 – CP10 CP11 CP13 CP12 CP14 J79-0312-09 A/3 Side1 J79-0312-09 B/3...
  • Page 57 NX-420 PC BOARD DISPLAY UNIT (X54-3760-XX) -10: K3 -12: K Component side view (J79-0312-09) Ref. No. Address Ref. No. Address Side2 Component side Layer 1 Layer 2 Layer 3 Layer 4 Foil side...
  • Page 58 NX-420 PC BOARD DISPLAY UNIT (X54-3760-XX) -10: K3 -12: K Foil side view (J79-0312-09) Ref. No. Address Ref. No. Address Component side Layer 1 Layer 2 Layer 3 Layer 4 Foil side...
  • Page 59 NX-420 PC BOARD DISPLAY UNIT (X54-3760-XX) -10: K3 -12: K Foil side view (J79-0312-09) MIC+ J79-0312-09 MIC– J79-0312-09 A/3 J79-0312-09 B/3...

  • Page 60: Tx-Rx Unit (X57-8370-10)

    NX-420 PC BOARD TX-RX UNIT ( X57-8370-10 ) Component side view (J79-0388-09) D501 Q509 C651 R507 IC603 C548 IC501 IC600 R612 C652 C508 IC602 C647 R523 R622 R631 C631 L606 C633 R515 C645 R620 C674 L507 C632 R607 L605 R624 L612 C644 C673...
  • Page 61 NX-420 PC BOARD TX-RX UNIT ( X57-8370-10 ) Component side view (J79-0388-09) Q107 CN902 R149 D500 R531 Q502 C147 C548 CN604 C161 R524 F500 C141 R153 Q504 CP604 C553 C656 C536 C554 R127 C657 D505 Q902 C909 C906 R526 C907 R517 R902 C542...
  • Page 62 NX-420 PC BOARD TX-RX UNIT ( X57-8370-10 ) Foil side view (J79-0388-09) R801 L118 L217 C238 C237 R211 L117 L116 L119 C181 C192 C185 C183 L219 L100 C190 L114 R151 C105 R108 C114 C106 R147 R101 C103 L101 R110 C111 C110 R152 D412...
  • Page 63 NX-420 PC BOARD TX-RX UNIT ( X57-8370-10 ) Foil side view (J79-0388-09) L307 L213 R207 C226 C228 L212 C227 XF300 C229 R211 L214 Q200 IC200 R210 R202 C200 C341 R335 C344 C202 C340 L204 C203 R317 C337 L206 R331 C209 C213 C217 R545...

  • Page 64: Level Diagram

    NX-420 LEVEL DIAGRAM Receiver Section RF (Center Frequency) IF1 (49.95MHz) IF2 (450kHz) –119.7dBm –97.9dBm –116.7dBm –103.9dBm –117.3dBm –90.6dBm –43.7dBm IF Amp FM IC ASIC Mixer C237 C236 C222 C340 C334 C329 IC200 L118 L217 L212 XF300 IC301 CF301 IC607 Q301 Q200 AF (1kHz) 183.9mVrms...

  • Page 65: Interconnection Diagram

    NX-420 INTERCONNECTION DIAGRAM X54-3760-XX * LCD DISPLAY UNIT X54-3760-XX A/3 SECTION CN500 X54-376 ENC1 ENC2 ENC4 ENC3 TX-RX UNIT VOL_GND X57-8370-10 CN604 /EMG /EMG...

  • Page 66: Schematic Diagram

    NX-420 SCHEMATIC DIAGRAM L C D ✽ X54-3760-XX R65 R66 R67 R71 R72 3.3k 3.3k 3.3k 3.3k 6.8k 2.2k X54-3760-XX R75 R76 2.2k 680 0.01u 0.047u 1000p 0.047u 680p 0.01u DISPLAY UNIT (X54-3760-XX)(A/3) TX/BUSY LED ✽ ✽ CP11 1kx4 LEDR LEDG 1kx4 R:6.04V...
  • Page 67 NX-420 SCHEMATIC DIAGRAM DISPLAY UNIT (X54-3760-XX) (A/3) ✽ X54-3760-XX ✽ 3.3k 3.30V DISP_VER VCO MOD/VREF 100x4 SQ_SW /EVCS SCK0 TC75W51FK(F) SCK0 SDO0 oUTA SDI0 1000p 0.01u oUTB SDO0 ✽ DISP_VER LEDR VoUT3 VoUT2 LEDG 0.01u VoUT4 VoUT1 /EVCS D/A CONV VIN4 VIN1 /LCDCS...
  • Page 68 NX-420 SCHEMATIC DIAGRAM TX-RX UNIT(X57-8370-10) L606 33MSRAM A[16] 3.30V C647 A[0] A[15] D[9] A[11] A[16] D[11] A[19] VCC1 A[15] DQ11 A[20] VSS1 D[1] D[13] FRASH MEMORY A[5] A[9] A[5] DQ13 SRAM D[15] A[1] IC600 A[10] DQ15 A[14] IC603 29PL032J70BFI A[11] D[5] VSS1 L1024GL-70LLI...
  • Page 69 NX-420 SCHEMATIC DIAGRAM TX-RX UNIT (X57-8370-10) L601 L602 R545 R460 L603 R617 4.7k CLK2 R618 ASQDET 4.7k 15MDSP 33MDSP 1.50V 3.30V DGND DGND 33MDSP HINT VSS_6 CVDD_6 VSS_5 CVDD_7 RESET VSS_4 CVDD_8 C601 VSS_3 CVDD_9 VSS_2 CVDD_10 VSS_1 C602 CVDD_11 X2/CLKIN CVDD_12 A’[0]...
  • Page 70 NX-420 SCHEMATIC DIAGRAM TX-RX UNIT (X57-8370-10) X600 L77-3015-05 33MC 3.30V 3 oUTPUT C666 0.01u IC606 SM5023CNDH-G 0.02V C667 1u R639 R644 CLK2 4 VCC C660 C668 0.1u ASQDET 0.01u INHN 33AA C673 BUFF R641 0.01u 470k C674 DGND3 XTALI C675 XTALo DGND2 DGND1...
  • Page 71 NX-420 SCHEMATIC DIAGRAM TX-RX UNIT (X57-8370-10) 7.50V 4.97V F500 L502 CN501 2.5A REVERSE Li-ion PROTECT BATTERY 7.5V R500 270k CN503 CN500 AVR (50C) R:7.50V T:7.40V C513 100p C514 100p 3.3V C515 6800p L500 VOL_GND C516 100p CN502 C518 100p ENC3 IC503 R506 NJM2878F4-33...
  • Page 72 NX-420 SCHEMATIC DIAGRAM TX-RX UNIT (X57-8370-10) 50CS C427 100p L400 TEMP L404 R422 R419 R420 C411 0.01u 0.01u C412 100p C413 X400 GND1 NC_1 L401 C405 CPout GND2 oUTPUT R415 4.7u NC_2 1000p VCCcp NC_3 LD/PS PLL SYSTEM C422 C425 IC400 NC_4 SKY72310-362...
  • Page 73 NX-420 SCHEMATIC DIAGRAM TX-RX UNIT (X57-8370-10) 50CS 50CS C460 D404,D406 L414 R447 VCO FREQ CONT VCO FREQ ASSIST R:1.18V R:4.08V 270n T:1.18V T:4.08V L423 D404 VCO(TX/RX) D403 L405 C449 L411 C467 R427 C478 270n 0.5p 1SV323F 1SV325F 100p R:4.43V R:0.73V T:4.42V R:3.68V C479...
  • Page 74 NX-420 SCHEMATIC DIAGRAM TX-RX UNIT (X57-8370-10) 50CS C113 PRE-DRIVE R:0V D412 Q102 T:4.86V 2SK3077F C121 R117 C124 RN142S D411,D412 100p RF SW R104 R:0V T:1.21V 3.9k RF AMP L427 R:0V Q101 T:0.99V C190 C106 2SC5636 R:4.48V C495 R:0V C489 C492 C493 T:4.47V 100p...
  • Page 75 NX-420 SCHEMATIC DIAGRAM TX-RX UNIT (X57-8370-10) L102 C171 L115 DRIVE 100p Q104 D102,D103 RD01MUS1-T113 D102 H:1.47V FINAL L:1.38V ANT SW H:7.34V L118 R:0V H:7.31V Q106 L:7.42V L191 HVC131 L79-1468-05 R120 T:0.83V L:7.41V RD07MUS2BT122 R152 C169 D103 C183 C185 C175 C177 H:1.25V L119 1.2n...

  • Page 76: Block Diagram

    NX-420 BLOCK DIAGRAM TX-RX unit (X57-8370-10) Q403 2SC5383-T111 D410 HSC119 Ripple 50CS Filter X600 L77-3015-05 Q404 EM6M1 IC606 18.432MHz Q406 FJ330301 IC400 SM5023CNDH-G SKY72310-362 PCK_DSP TCXO /PCS_DSP PLL MOD Loop Filter IC600 IC603 TCXO 33MDSP Flash IC601 15MDSP SRAM X400 16.8MHz IC404 (1/2) TC75W51FK(F) SD01...
  • Page 77 NX-420 BLOCK DIAGRAM TX : 806 - 825MHz TA : 851 - 870MHz /T_R Q407 Q408 D411,D412 Q101 Q102 Q104 Q106 D102,103 HVC131 L118 2SC5636 2SC5636 RN142S*2 2SC5636 2SK3077 RD01MUS1-T113 RD07MUS2BT122 D104,105 RN142S L79-1468-05 BUFF Pre-Drive Drive Final Doubler Q405 2SC5636 Q108 FJ330301...
  • Page 78 NX-420 BLOCK DIAGRAM...

  • Page 79: Specifications

    Audio Distortion ..........Less than 3% Modulation ..........16K0F3E, 11K0F3E, 8K30F1E, 8K30F1D, 8K30F7W, 4K00F1E, 4K00F1D, 4K00F7W, 4K00F2D Analog measurements made per TIA/EIA 603 and specifi cations shown are typical. Kenwood reserves the right to change specifi cations without prior notice or obligation.
  • Page 80 NX-420...
  • Page 81 NX-420 NX-420 PC BOARD PC BOARD DISPLAY UNIT (X54-3760-XX) -10: K3 -12: K DISPLAY UNIT (X54-3760-XX) -10: K3 -12: K Component side view (J79-0312-09) Component side view (J79-0312-09) J79-0312 -09 C/3 – CP10 CP11 CP13 CP12 CP14 J79-0312-09 A/3 Side1 Ref.
  • Page 82 NX-420 NX-420 PC BOARD PC BOARD DISPLAY UNIT (X54-3760-XX) -10: K3 -12: K DISPLAY UNIT (X54-3760-XX) -10: K3 -12: K Foil side view (J79-0312-09) Foil side view (J79-0312-09) MIC+ J79-0312-09 MIC– J79-0312-09 A/3 Ref. No. Address Ref. No. Address Component side J79-0312-09 B/3 Layer 1 Layer 2...
  • Page 83 NX-420 NX-420 PC BOARD PC BOARD TX-RX UNIT ( X57-8370-10 ) TX-RX UNIT ( X57-8370-10 ) Component side view (J79-0388-09) Component side view (J79-0388-09) Q107 CN902 D501 R149 Q509 C651 R507 D500 R531 Q502 IC603 C147 C548 IC501 CN604 IC600 R612 C161 C652...
  • Page 84 NX-420 NX-420 PC BOARD PC BOARD TX-RX UNIT ( X57-8370-10 ) TX-RX UNIT ( X57-8370-10 ) Foil side view (J79-0388-09) Foil side view (J79-0388-09) L307 L213 R207 C226 R801 C228 L118 L217 L212 C227 XF300 C238 C237 C229 R211 L214 L116 L117 L119...
  • Page 85 TX-RX UNIT(X57-8370-10) ✽ L CD X54-3760-XX R65 R66 R67 R71 R72 ✽ X54-3760-XX 7.50V 4.97V L102 F500 L502 50CS 50CS 50CS 50CS C171 L115 3.3k 3.3k 3.3k 3.3k 6.8k 2.2k CN501 C427 DRIVE ✽ 3.3k L601 2.5A C113 Q104 D102,D103 100p Li-ion REVERSE...
  • Page 86 TX-RX unit (X57-8370-10) Q403 2SC5383-T111 D410 HSC119 Ripple TX : 806 - 825MHz 50CS Filter X600 TA : 851 - 870MHz L77-3015-05 Q404 EM6M1 IC606 /T_R 18.432MHz Q406 FJ330301 SM5023CNDH-G IC400 Q407 Q408 D411,D412 Q101 Q102 Q104 Q106 D102,103 HVC131 L118 SKY72310-362 2SC5636...

This manual is also suitable for:

Nx-420 seriesNx-420 k3

Table of Contents