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Kenwood FM Transceiver TK-481 Service Manual

800mhz/900mhz fm transceiver.
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Copyright 2006 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, for
any purpose without the prior written permission of Kenwood.
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 contained herein. Kenwood reserves
the right to make changes to any products herein at any time for improvement purposes.


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   Summary of Contents for Kenwood FM Transceiver TK-481

  • Page 1

    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 contained herein. Kenwood reserves...

  • Page 2: Table Of Contents

    800MHz/900MHz FM TRANSCEIVER TK-480/481 SERVICE MANUAL REVISED II This service manual applies to products with 30100001 or subsequent serial numbers. Whip antenna (T90-0636-25) : TK-480 (T90-0640-25) : TK-481 Knob (ENC) (K29-5232-03) Knob (VOL) (K29-5231-03) Knob (PTT) (K29-5157-03) Photo is TK-480/481 K2 type. (Produced in Singapore) ©...

  • Page 3: General

    KPG-35D for those radios. TK-480/481 transceivers with a serial number of 30100001 or greater have a red triangle in the KENWOOD logo label (B43-1139-04) on the front panel. You will also find the model name plate marked as “Ver 2.0” on the rear of the transceiver.

  • Page 4: Operating Features

    1. Operation Features The TK-480/481 is an 800/900MHz band EFJ LTR™-com- patible trunked radio designed to operate in both trunked and conventional modes. The programmable features are summarized. Model Trunking mode Conventional mode This model can handle up to 32 systems with up to 250 groups in each system.

  • Page 5

    TK-480/481 Auto TEL Automatically connects available repeaters that are con- nected to telephone circuits when operating as LTR system. The time allocated to search for available repeaters is 60 seconds, after which connection failure occurs, a DTMF tone is output and the function terminates. If connection to an available circuit is made, only ID 253, EOT or hang-up time-out can terminate the function.

  • Page 6: Scan Operating

    System up/down When the key is pressed each time, the system number to be selected is incremented/decremented and repeats if held for one second or longer. Telephone disconnect Pressing this key ends an RIC connection (disconnects the telephone line). None Sounds error operation beep, and no action will occur.

  • Page 7

    TK-480/481 To unlock a system, select the system and press the key. The Delete ( ) indicator disappears to indicate that the sys- tem has returned to the scan sequence. The revert system is scanned even if it is locked out. If there a locked system, the Delete ( ) indicator flashes during fixed scanning.

  • Page 8

    4-5. Radio password When the password is set in the transceiver, user can not use the transceiver unless enter the correct password. This code can be up to 6 digits from 0 to 9 and input with the keypad or selector, and “S” key. 4-6.

  • Page 9: Option Signalling

    T h e A l p h a n u m e r i c T w o - w a y P a g i n g F u n c t i o n (FleetSync™) is a Kenwood proprietary protocol. It enables a variety of paging functions.

  • Page 10

    Status 80~99 (Special) Status numbers from 80 to 99 are reserved for special purposes. Entering these statuses from the DTMF keypad can be inhibited. Please notice that the following status numbers are used for special purposes; 80~87 : Reserved for future use. 88 : Terminates to emergency mode.

  • Page 11: Audible User Feedback Tones

    TK-480/481 Number of Retries Number of Retries is the maximum number of retry transmission when no acknowledgement is received in the Maximum ACK Wait Time. Increase this item to improve data communication reliability. TX Busy Wait Time TX Busy Wait Time is the maximum amount of time be- fore giving up the data transmission when the channel (or all the repeater channels for Trunking mode) is busy.

  • Page 12

    OPERATING FEATURES / REALIGNMENT 7-16. Intercept Tone This tone indicates that the transceiver is out of range. It indicates that the PTT button is pressed, and transmission has started, but the repeater cannot be connected and talk- ing is not possible. It is output until the PTT button is re- leased.

  • Page 13: Realignment

    TK-480/481 5. PC Mode 5-1. Preface The TK-480/481 transceiver is programmed by using a personal computer, programming interface (KPG-36) and programming software (KPG-49D). The programming software can be used with an IBM PC or compatible. Figure 1 shows the setup of an IBM PC for programming.

  • Page 14: Clone Mode

    Notes: • To start the Firmware Programmer from KPG-49D, the Fpro path must be set up by KPG-49D Setup. • This mode cannot be entered if the Firmware Program- ming mode is set to Disable in the Programming soft- ware (KPG-49D). •...

  • Page 15: Circuit Description

    TK-480/481 1. Overview This transceiver is an 800/900MHz band EFJ LTR™ trunked system compatible FM portable transceiver that can be programmed to operate on both LTR and conventional systems. 2. Circuit Configuration by Frequency The receiver is a double-conversion superheterodyne with a first intermediate frequency (IF) of 44.85MHz and a second IF of 455kHz.

  • Page 16

    3-3. Audio amplifier circuit The demodulated signal from IC9 is amplified by IC8 (2/ 2), high-pass filtered, low-pass filtered, high-pass filtered, band-eliminate filtered,and de-emphasized by IC12. The signal then goes through an AF amplifier IC3 (2/2), an electronic volume control (IC4), and an AF switch (Q310 is on), and is routed to audio power amplifier (IC300), where it is amplified and output to the internal speaker.

  • Page 17

    TK-480/481 The signal from microphone passes through the limitter circuit in D11, and through the high-pass filter, the ALC cir- cuit, the low-pass filter, the high-pass filter, and pre-empha- sis/IDC circuit in IC12. When encoding DTMF, mute switch (Q7) is turned OFF for muting the microphone input signal. The signal passes through the D/A converter (IC4) for the maximum deviation adjustment, and enters the summing amplifier consisting of IC3 (2/2), and is mixed with the low...

  • Page 18

    5. Frequency Synthesizer Unit 5-1. Frequency synthesizer The frequency synthesizer consists of the VCXO (X2), VCO (IC14), PLL IC (IC11) and buffer amplifiers. The VCXO generates 16.8MHz. The frequency stability is 1.5ppm within the temperature range of –30 to +60 C. The frequency tuning and modulation of the VCXO are done to apply a voltage to pin 1 of the VCXO.

  • Page 19

    TK-480/481 6-2. Low battery warning The battery voltage is monitored by the microprocessor (IC15). When the battery voltage falls below the voltage set by the Low Battery Warning adjustment, the red LED flashes to notify the operator that it is time to replace the battery.

  • Page 20

    7-2. Decode • Low-speed data (QT,DQT,LTR) The demodulated signal from the IF IC (IC9) is amplified by IC8 (1/2) and passes through a low-pass filter (IC10) to remove audio components. The signal is input to pin 23 of the CPU. The CPU digitizes this signal, performs processing such as DC restoration, and decodes the signal.

  • Page 21: Semiconductor Data

    TK-480/481 Microprocessor : 30622M8A-4F9GP (TX-RX Unit IC15) Pin function Pin No. Port name I/O LSDOUT Low speed data output. HSDOUT High speed data output. HSDIN Not used. DTMSTD DTMF decode IC data detect input. SELF Not used. BYTE +5V. CNVSS GND.

  • Page 22

    Shift Register 1 : BU4094BCFV (TX-RX Unit IC18) Pin No. Port Port name STRB Strobe DATA Data Clock LEDR Red LED. H : On, L : Off LEDG Green LED. KEYBLT Key backlight. H : On, L : Off MMUTE MIC mute.

  • Page 23: Block Diagram

    TK-480/481 PLL System : SA7025DK (TX-RX Unit IC11) Block diagram CLOCK DATA STROBE TEST Pin description Pin No. Symbol CLOCK Serial clock input. DATA Serial data input. STROBE Serial strobe input. Digital ground. Prescaler positive input. Prescaler negative input. Prescaler positive supply voltage. This pin supplies power to the prescaler and RF input buffer. Reference divider input.

  • Page 24: Description Of Components

    DESCRIPTION OF COMPONENTS DISPLAY UNIT (X54-3210-XX) Ref. No. Use/ Function Operation/Condition IC300 Audio power amplifier IC301 Counter Q300 DC switch Q301 DC switch Q302 Transistor DC switch Q303 Transistor DC switch Q304 Transistor DC switch Q305 Transistor Current driver / Audio amp AVR Q306 Transistor DC switch...

  • Page 25: Parts List

    A02-3658-03 CABINET ASSY (4KEY) A02-3659-03 CABINET ASSY (16KEY) A62-0981-04 PANEL ASSY B09-0363-03 CAP (SP/MIC) B38-0810-05 LCD ASSY B43-1139-04 BADGE (KENWOOD) B46-0470-00 WARRANTY CARD B62-1483-00 INSTRUCTION MANUAL B72-1968-04 MODEL NAME PLATE B72-1969-04 MODEL NAME PLATE E04-0406-05 RF COAXIAL RECEPTACLE (SMA) E23-1049-04...

  • Page 26

    Ref. No. Address Parts No. parts R300 RK73GB1J103J CHIP R R301 RK73FB2A101J CHIP R R302 RK73GB1J470J CHIP R R303 RK73GB1J471J CHIP R R304 RK73GB1J182J CHIP R R305 RK73GB1J104J CHIP R R306 R92-1252-05 CHIP R R307 RK73GB1J821J CHIP R R308 RK73GB1J153J CHIP R R309 R92-1252-05...

  • Page 27

    TK-480/481 TX-RX UNIT (X57-5630-XX) Ref. No. Address Parts No. parts CK73GB1C104K CHIP C CK73GB1C333K CHIP C CK73GB1C104K CHIP C CK73GB1H562J CHIP C CK73GB1E103K CHIP C CC73GCH1H121J CHIP C CK73GB1C683K CHIP C CC73GCH1H101J CHIP C C82,83 CK73GB1H562J CHIP C CC73GCH1H150J CHIP C CK73GB1H272J CHIP C CK73GB1C333K...

  • Page 28

    Ref. No. Address Parts No. parts E40-5890-05 FLAT CABLE CONNECTOR (24P) CN4-9 E23-1002-05 TERMINAL CN10 E23-0342-05 TEST TERMINAL CN11,12 E23-1002-05 TERMINAL F53-0130-05 FUSE (3A) F53-0217-05 FUSE (3A) L79-1072-05 TUNING COIL CF1,2 L72-0924-05 CERAMIC FILTER (455KHZ) CF1,2 L72-0939-05 CERAMIC FILTER (455KHZ) L92-0149-05 FERRITE CHIP L40-1095-34...

  • Page 29

    TK-480/481 TX-RX UNIT (X57-5630-XX) Ref. No. Address Parts No. parts RN73GH1J913D CHIP R RK73GB1J223J CHIP R RK73GB1J334J CHIP R RN73GH1J682D CHIP R RK73GB1J154J CHIP R RK73GB1J101J CHIP R RK73GB1J155J CHIP R RK73GB1J101J CHIP R RN73GH1J683D CHIP R RK73GB1J474J CHIP R RK73GB1J560J CHIP R RN73GH1J682D...

  • Page 30

    Ref. No. Address Parts No. parts R419-422 R92-1252-05 CHIP R R423 RK73GB1J473J CHIP R 1SR154-400 DIODE MA2S111 DIODE MA742 DIODE D4,5 MA2S077 DIODE UDZS4.7B ZENER DIODE HVU131 DIODE MA2S111 DIODE D9,10 MA2S077 DIODE MA742 DIODE MA2S111 DIODE D17,18 DA221 DIODE TA75W01FU IC (BUFFER AMP) RN5VL42C...

  • Page 31: Exploded View

    TK-480/481 21x2 MIC300 TX-RX unit When you repair or exchange the display unit, please exchange the sheet (24) as well. Display unit (B/2) 701 (Chassis) EXPLODED VIEW S/No. label Parts with the exploded numbers larger than 700 are not supplied. 22x2 Display unit (A/2) : N14-0569-04...

  • Page 32: Packing

    7 Warranty card (B46-0470-00) 9 Instruction manual (B62-1483-00) 4 Cap (SP/MIC) (B09-0363-03) 42 Screw set (N99-2004-05) 32 Hook (J29-0658-05) PACKING 47 Whip antenna (T90-0636-25) : TK-480 (T90-0640-25) : TK-481 TK-480/481 50 Battery assy (W09-0900-35) Insulation sheet 28 Packing fixture (H12-3014-02) 29 Item carton case (H52-1096-12) : TK-480 (H52-1097-12) : TK-481...

  • Page 33: Adjustment

    TK-480/481 Test Equipment Required for Alignment Test Equipment 1. Standard Signal Generator (SSG) 2. Power Meter 3. Deviation Meter 4. Digital Volt Meter (DVM) 5. Oscilloscope 6. High Sensitivity Frequency Counter 7. Ammeter 8. AF Volt Meter (AF VTVM) 9. Audio Generator (AG) 10.

  • Page 34

    • Panel tuning 2: RED (RX AF OUTPUT) 3: BLACK (RX AF OUTPUT) 5: WHITE (MIC INPUT) SCREW 6: BROWN (MIC GND) TUBE 7: BLUE (PTT SW) GND 8: YELLOW (PF SW) 10: BROWN (GND) 11: GREEN (5M) BLU (7) To Radio BRN (10) 100 10V...

  • Page 35: Test Mode

    TK-480/481 Test Mode Test mode operating features This transceiver has a test mode. To enter test mode, press [A] key and turn power on. Hold [A] key until test channel No. and test signalling No. appears on LCD. Test mode can be inhibited by programming. To exit test mode, switch the power on again.

  • Page 36

    • Transceiver tuning (To place transceiver in tuning mode) System appears on LCD. Set system according to tuning requirements. LCD display (Test mode) 1 – System No. Group No. Press [S], now in tuning mode. Use [ B] button to write tuning data through tuning modes, and channel selector knob to adjust tuning requirements (1 to 256 appears on LCD).

  • Page 37

    TK-480/481 Common Section Item Condition 1. Setting 1) BATT terminal voltage : 7.5V Standard modulation MOD : 1kHz DEV : 3kHz (TK-480) 1.5kHz (TK-481) 2. VCO lock 1) SYS – GRP : 1 – 1 voltage 2) SYS – GRP : 7 – 1 PTT : ON 3) SYS –...

  • Page 38

    Item Condition 9. DQT BAL 1) SYS – GRP : 4 – adjustment Select BAL in tuning mode. Deviation meter filter setting LPF : 3kHz HPF : OFF PTT : ON 10. MAX DEV 1) SYS – GRP : 4 – adjustment Select MAX in tuning mode.

  • Page 39

    TK-480/481 Item Condition 15. QT DEV 1) SYS – GRP : 4 – adjustment MIC input : OFF Select FQT in tuning mode. Deviation meter filter setting LPF : 3kHz HPF : 50Hz De-emphasis : 750 s PTT : ON 16.

  • Page 40

    Item Condition 22. BATT 1) SYS – GRP : 4 – 1 detection BATT terminal voltage : 5.7V check PTT : ON 2) BATT terminal voltage : 6.5V PTT : ON Note : When the CPU is changed these adjustment values will become suitable values for NPSPAC, the deviations except MAX DEV in NPSPAC band are automatically adjusted.

  • Page 41: Terminal Function

    TK-480/481 CN No. Pin No. Name I/O TX-RX UNIT (X57-5630-XX) : TX-RX section O Power input after passing through the fuse. O Power input after passing through the fuse. Power output after power switch. Power output after power switch. O 5V. Volume level input for audio control.

  • Page 42: Pc Board Views

    DISPLAY UNIT (X54-3210-XX) -10 : K -11 : K2 Component side view S301 D301 J72-0517-22 S302 S303 LAMP LCD ASSY CN302 MIC300 – TK-480/481 PC BOARD VIEWS Ref No. Address D301 D305 D306 D307 D308 D309 D310 J72-0517-22 Component side Pattern 1 Pattern 2 Pattern 3...

  • Page 43

    TK-480/481 PC BOARD VIEWS DISPLAY UNIT (X54-3210-XX) -10 : K -11 : K2 Foil side view J72-0517-22 CN303 CN300 CP300 R306 R325 D320 R324 Q301 C340 R331 R314 R332 C318 Q310 IC300 L301 Q305 SP– L300 Q309 L303 R326 CP303 CP302 R319 D304...

  • Page 44

    DISPLAY UNIT (X54-3210-XX) -10 : K -11 : K2 Component side view + Foil side S301 D321 R300 R302 R304 R303 R305 C302 + CN301 C328 S300 D301 R310 Q303 C305 R307 Q302 J72-0517-22 CN303 S302 S303 LAMP LCD ASSY CN302 R301 R312 R311...

  • Page 45: Tx-rx Unit (x57-5630-xx)

    TK-480/481 PC BOARD VIEW TX-RX UNIT (X57-5630-XX) -10 : TK-480 -11 : TK-481 Component side view R419 MONI R420 LAMP C111 C112 RXEMAI RXWMAO RXAO C100 RXAI RSSI AUXRXD PTTOUT AUXTXD AUDIOBEEP TXAO R148 PTTIN TXAI/MUTE DI/ANI DTA144EE 2SB1132 IMN10 DTC114EE DTC144EE 2SA1832...

  • Page 46

    TX-RX UNIT (X57-5630-XX) -10 : TK-480 -11 : TK-481 R134 C165 C172 R146 CN12 IC21 C164 R143 R131 C170 R145 R144 C171 C161 C139 C132 C193 R105 C129 TK11250BM 30622M8A-4F9GP AT29C020-90TI W29C020C90 TC35453F M68757H SA7025DK M68757L Foil side view C177 C182 C152 R165...

  • Page 47

    TK-480/481 PC BOARD VIEW TX-RX UNIT (X57-5630-XX) -10 : TK-480 -11 : TK-481 Component side view + Foil side R419 MONI R420 LAMP R276 R421 R408 C261 C106 IC17 C111 C112 CP21 CP14 CP11 CP16 CP18 CP13 CP22 CP20 CP15 CP12 CP17 CP19...

  • Page 48: Schematic Diagram

    TK-480/481 SCHEMATIC DIAGRAM Note : Components marked with a dot (·) are parts of pattern 1.

  • Page 49: Block Diagram

    TK-480/481 TK-480/481 BLOCK DIAGRAM...

  • Page 50: Level Diagram (tk-480)

    TK-480/481 LEVEL DIAGRAM (TK-480)

  • Page 51: Level Diagram (tk-481)

    TK-480/481 LEVEL DIAGRAM (TK-481)

  • Page 52: Knb-16a/17a (ni-cd Battery)

    KNB-16A/17A (Ni-Cd BATTERY) / KPG-36 (PROGRAMMING INTERFACE CABLE) / KSC-19 (CHARGER) KNB-16A KNB-17A External View External View KNB-16A KNB-17A Circuit Diagram Circuit Diagram Discharge pin side – Breaker Breaker Breaker (70 5 C) (70 5 C) (80 5 C) Diode Diode Thermister –...

  • Page 53: Specifications

    TK-480/481 General Frequency Range RX ... TK-480 : 851 to 870MHz TX ... TK-480 : 806 to 825MHz (851 to 870MHz : Talk-Around) Systems ... Maximum 32 Groups ... Maximum 250 Conventional Channels ... Maximum 600 Channel Spacing ... TK-480 : 25kHz (PLL channel step 12.5kHz) Battery Voltage ...

  • Page 54


  • Page 55

    Mechelsesteenweg 418 B-1930 Zaventem, Belgium KENWOOD ELECTRONICS FRANCE S.A. 13, Boulevard Ney, 75018 Paris, France KENWOOD ELECTRONICS U.K. LIMITED KENWOOD House, Dwight Road, Watford, Herts., WD1 8EB United Kingdom KENWOOD ELECTRONICS EUROPE B.V. Amsterdamseweg 37, 1422 AC Uithoorn, The Netherlands KENWOOD ELECTRONICS ITALIA S.p.A.

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