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Kenwood TK-280 Service Manual

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VHF FM TRANSCEIVER
TK-280
SERVICE MANUAL
REVISED
Knob (PTT etc)
(K29-5157-03)
Photo is K3 type with KRA-14
GENERAL ................................................................................. 2
Helical antenna
(T90-0679-05):M
SYSTEM SET-UP ..................................................................... 2
OPERATING FEATURES ......................................................... 3
Knob (ENC)
(K29-5232-03)
REALIGNMENT ...................................................................... 11
CIRCUIT DESCRIPTION ........................................................ 16
Knob (VOL)
SEMICONDUCTOR DATA ..................................................... 22
(K29-5231-03)
DESCRIPTION OF COMPONENTS ....................................... 27
PARTS LIST ............................................................................ 28
EXPLODED VIEW .................................................................. 34
Panel assy
(A62-0535-04)
PACKING ................................................................................ 35
Badge
ADJUSTMENT ........................................................................ 36
(B43-1106-14)
TERMINAL FUNCTION .......................................................... 44
Cabinet assy
(A02-2054-53)
:K,K2,M (4 keys)
(A02-2055-53)
SCHEMATIC DIAGRAM ......................................................... 57
:K3,K4 (16 keys)
BLOCK DIAGRAM .................................................................. 61
LEVEL DIAGRAM ................................................................... 63
OPTINONS ............................................................................. 64
SPECIFICATIONS ............................................... BACK COVER
Packing
(G53-0840-02):K,K2,M (4 keys)
(G53-0841-02):K3,K4 (16 keys)
©
1999-4 PRINTED IN JAPAN
B51-8454-10(S) 1217
This service manual is same at the TK-280(B51-8454-00)
service manual with destination K, K3 and M with the
exception of new destination, K2 and K4.
CONTENTS
DISPLAY UNIT (X54-3210-XX) ........................................... 45
TX-RX UNIT (X57-5740-XX) ............................................... 51
CAUTION
When using an external power connector,
please use with maximum final module
protection of 9V.

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  Summary of Contents for Kenwood TK-280

  • Page 1: Table Of Contents

    SERVICE MANUAL © REVISED 1999-4 PRINTED IN JAPAN B51-8454-10(S) 1217 This service manual is same at the TK-280(B51-8454-00) service manual with destination K, K3 and M with the exception of new destination, K2 and K4. CONTENTS GENERAL ................. 2 Helical antenna (T90-0679-05):M SYSTEM SET-UP ..............
  • Page 2: General

    WE CANNOT guarantee oscillator stability when using applies to all parts : components, kits, or chassis. If the part channel element manufactured by other than KENWOOD or number is not known, include the chassis or kit number of which its authorized agents.
  • Page 3: Operating Features

    (or group number). 1. Operation Features System numbers (or group numbers) not set are skipped. The TK-280 is an VHF FM radio designed to operate in Caution : The FPU (KPG-49D) allows selecting between both trunking format and conventional format. The system selector and group selector.
  • Page 4 TK-280 OPERATING FEATURES 0 S, A, 2 B, and C 3 key (Programmable) the underscore disappears and the AUX ports turns to the deactive level. - DTMF keypad (keypad model only) Press the keys on the telephone keypad to send DTMF 3) Channel up/down (Conventional Format) tones.
  • Page 5 TK-280 OPERATING FEATURES 9) Group up/down previously transmitted DTMF code. Pressing [PTT] at this time, When the key is pressed each time, the group number to transmits the code that is currently displayed. be selected is incremented/decremented and repeats if held for one second or longer.
  • Page 6: Scan Operating

    TK-280 OPERATING FEATURES 25) Telephone disconnect (Trunking Format) or scrambler ( _ ) function. The delete/add indicator shows Pressing this key ends an RIC connection (disconnects the the systems locked out of the scanning sequence. Selective telephone line). call and scrambler are optional functions that can be programmed.
  • Page 7 TK-280 OPERATING FEATURES 7) Group scan operation ● User selectable lockout If the scan lockout feature is programmed to a key, the user Group scan can be programmed for each group. In addition can lock systems out of the scan sequence with the key. To...
  • Page 8 TK-280 OPERATING FEATURES 2 Non-priority channels detects a signal during scan. For the 9) Temporarily Delete/Add channels that can be selected with the group or channel It is possible to delete or add channel temporarily during selector when the scan does not occur, adds an indicator scan.
  • Page 9 TK-280 OPERATING FEATURES 6) Battery Warning selected system (If during scanning, the scan stops). This transceiver has battery warning feature. If the low 4) Transpond voltage is detected during transmission, the transceiver warns it by flashing red "LED". This feature can be programmed to turn on and off for each Then more low voltage is detected during transmission, the group.
  • Page 10: Audible User Feedback Tones

    TK-280 OPERATING FEATURES 3) "TOT" Reset Time Alert/Transpond AF Mute Open The transceiver has "TOT" reset timer. This timer is the Triggers at match with QT/ Triggers at match with QT/ minimum wait time allowed during a transmission that will reset DQT/ID+DTMF(2tone);Both DQT/ID+DTMF(2tone);Both...
  • Page 11: Realignment

    TK-280 OPERATING FEATURES/REALIGNMENT • Group Call Tone • Ringing tone (Trunking Format) The group call tone informs the user of a group call in DTMF/ This tone indicates that the transceiver can use the repeater 2Tone Option Signaling. This tone repeats 7 times.
  • Page 12 4. Set the firmware to be updated by File select (=F1). The KPG-36 is required to interface the TK-280 to the 5. Turn the TK-280 power ON with the [S] switch held down. computer. It has a circuit in its D-subconnector (25-pin) case Hold the switch down for two seconds until the display that converts the RS-232C logic level to the TTL level.
  • Page 13: Clone Mode

    8. Self Programming Mode Write mode for frequency data and signalling etc. Mainly 1. Turn the master TK-280 power ON with the [C] key held used by the person maintaining the user equipment. down. If the password is set to the TK-280, the TK-280 displays "CLONE LOCK".
  • Page 14 TK-280 REALIGNMENT Items set in Channel Setting Mode are as follows. Function settings Display Remarks Channel select CH or GRP X57-5740 RX Frequency RXF [LAMP] : Freq. On/Off switching Foil Side [A] : 2.5kHz/5kHz/6.25kHz/ 7.5kHz/1MHz step switching RX Signalling RXS...
  • Page 15 TK-280 REALIGNMENT 8-3. Function Setting Mode ● Flow Chart This is a mode for using the panel keys to make function settings without using the FPU, that operate on all channels. Self programming mode [LAMP] Pressing the [LAMP] when [SELF PROG] is displayed, sets the Function Setting Mode.
  • Page 16: Circuit Description

    TK-280 CIRCUIT DESCRIPTION 1. Overview D/A converter (IC8). The signal is amplified by RF amplifier (Q24), and passed through the bandpass filter (L31,33) and This transceiver is VHF/FM portable transceiver designed band-eliminate filter (L27,29) to remove the spurious signal to operate in the frequency range of 146 to 174MHz (K, K3, M) again.
  • Page 17 TK-280 CIRCUIT DESCRIPTION Q305 Q304 C266 INT.SP EXT.SP IC12 FM IF SYSTEM Q308 "H" : Wide IC300 "L" : Narrow Q301 Fig. 4 Audio amplifier circuit 3-5. Squelch circuit The output from IC12 enters FM IC again, then passed through a band-pass filter. The noise component output from IC12 is amplified by Q4 and rectified by D4 to produce a DC voltage corresponding to the noise level.
  • Page 18 1 of the VCXO. The output of the VCXO MUTE DTMF EXT. is applied to pin 8 of the PLL IC. IC13 The TK-280’s VCO consists of 2VCO and covers a dual Q300 range of the 190.85~218.85MHz (K,K3,M), 186.85~206.85MHz LIMIT COMP (K2,K4) and the 146~174MHz (K,K3,M), 136~162MHz (K2,K4).
  • Page 19 TK-280 CIRCUIT DESCRIPTION 6-2. Low battery warning The battery voltage is monitored by the microprocessor BUFF drive (TX : Low) (IC19). When the battery voltage falls below the voltage set by the Low Battery Warning adjustment, the red LED flashes to BUFF notify the operator that it is time to replace the battery.
  • Page 20 TK-280 CIRCUIT DESCRIPTION 7-2. Decode 7. Signalling Circuit ● Low-speed data (QT,DQT,LTR) 7-1. Encode The demodulated signal from the IF IC (IC12) is amplified ● Low-speed data (QT,DQT,LTR) by IC4 (2/2) and passes through a low-pass filter (IC11) to Low-speed data is output from pin 1 of the CPU. The signal remove audio components.
  • Page 21 TK-280 CIRCUIT DESCRIPTION 8. Power Supply Circuit 9. Optional Board Terminal Battery +B is supplied via a 3A fuse from the battery terminal Terminals for mounting the option board are provided at connected to the TX-RX unit. After passing through the power the bottom edge of the TX-RX unit.
  • Page 22: Semiconductor Data

    TK-280 SEMICONDUCTOR DATA Microprocesser : 30612M4A-407GP (TX-RX UNIT : IC19) ■ Pin function Port Port Function Function Name Name LSDOUT O Low speed data output. GND. HSDOUT High speed data output. 63~70 A0~A7 Flash memory address bus. HSDIN High speed data input.
  • Page 23: Block Diagram

    TK-280 SEMICONDUCTOR DATA Audio Processor : TC35453F (TX-RX Unit IC13) ■ Block diagram ■ Pin function Port Port Function Function No. Name No. Name RXFO RX audio filter output. Data synchronized clock input. RXGS RX audio signal level setting amplifier...
  • Page 24 TK-280 SEMICONDUCTOR DATA D/A Converter : M62364FP (TX-RX Unit IC8) ■ Block diagram ■ Pin function Pin No. Pin code I/O Function Pin No. Pin code I/O Function D/A converter input. 10,11 VO3,VO4 8-bit resolution D/A. VO1,VO2 8-bit resolution D/A.
  • Page 25: Pin Description

    TK-280 SEMICONDUCTOR DATA PLL System : SA7025DK (TX-RX Unit IC14) Audio Power Amplifier : TDA7053AT ■ Block diagram (Display Unit IC300) ■ Block diagram ■ Pin description ■ Pin description Pin No. Symbol Description Pin No. Symbol Description CLOCK Serial clock input.
  • Page 26 TK-280 SEMICONDUCTOR DATA VCO System : X58-4580-XX (SUB Unit : A1) Voltage Detector : RN5VL42C ■ Circuit diagram (TX-RX Unit IC3) ■ Block diagram (CMOS output) ■ Pin function Pin No. Pin code Function Output. Power supply. Ground. Counter : MC74HC4017F (Display Unit IC301) ●...
  • Page 27: Description Of Components

    TK-280 DESCRIPTION OF COMPONENTS DISPLAY UNIT (X54-3180-XX) Ref. No. Use/Function Operation/Condition Ref. No. Use/Function Operation/Condition IC300 Audio power amplifier Transistor Ripple filter IC301 Counter /Key scan Transistor DC switch / W/N audio amplitude adjust Q300 DC switch / INT MIC on/off...
  • Page 28: Parts List

    Parts No. Description Destination Address Parts No. Description Destination Ref. No. Ref. No. parts parts S70-0414-05 TACT SWITCH (AUX SW) TK-280 (Y50-487) A02-2054-53 CABINET ASSY(4 KEYS) K,K2,M T07-0347-05 SPEAKER A02-2055-53 CABINET ASSY(16 KEYS) K3,K4 T90-0679-05 HELICAL ANTENNA ACSY A62-0535-04 PANEL ASSY...
  • Page 29 TK-280 PARTS LIST DISPLAY UNIT (X54-3210-XX) TX-RX UNIT (X57-5740-XX) TX-RX UNIT (X57-5740-XX) Ref. No. Address Parts No. Description Destination Ref. No. Address Parts No. Description Destination parts parts R318 RK73GB1J104J CHIP R 100K J 1/16W CK73FB1A105K CHIP C 1.0UF R319...
  • Page 30 TK-280 PARTS LIST TX-RX UNIT (X57-5740-XX) Ref. No. Address Parts No. Description Destination Ref. No. Address Parts No. Description Destination parts parts C104 CK73GB1H102K CHIP C 1000PF K C187 CC73GCH1H270J CHIP C 27PF C105 CK73GB1E103K CHIP C 0.010UF K C189...
  • Page 31 TK-280 PARTS LIST TX-RX UNIT (X57-5740-XX) Ref. No. Address Parts No. Description Destination Ref. No. Address Parts No. Description Destination parts parts C245 CK73GB1H102K CHIP C 1000PF K L40-3371-36 SMALL FIXED INDUCTOR(33NH/8) C246 CC73GCH1H130J CHIP C 13PF L34-4568-05 AIR-CORE COIL(8T)
  • Page 32 TK-280 PARTS LIST TX-RX UNIT (X57-5740-XX) Ref. No. Address Parts No. Description Destination Ref. No. Address Parts No. Description Destination parts parts R123 RK73GB1J183J CHIP R J 1/16W RN73GH1J913D CHIP R D 1/16W R124 R92-1252-05 CHIP R 0 OHM RN73GH1J683D...
  • Page 33 TK-280 PARTS LIST TX-RX UNIT (X57-5740-XX) SUB UNIT (X58-4580-10) TX-RX UNIT (X57-5740-XX) Ref. No. Address Parts No. Description Destination Ref. No. Address Parts No. Description Destination parts parts Q13 -15 2SK1824 R284 R92-1252-05 CHIP R 0 OHM 2SC5108(Y) TRANSISTOR R294...
  • Page 34: Exploded View

    TK-280 EXPLODED VIEW Parts with the exploded numbers larger than 700 are not supplied.
  • Page 35: Packing

    TK-280 PACKING 6 Warranty card (B46-0470-00):K,K2,K3,K4 7 Instrution mamual 36 Carton Board (B62-0967-00):K,K2,K3,K4 (H13-1072-04) (B62-0988-00):M 3 Cap (B09-0363-03) 48 Screw set (N99-2004-05) 35 Packing fixture (H12-3014-02) ANT Helical antenna (T90-0679-05):M 40 Hook (J29-0618-15) 37 Item carton case (H52-1225-02) UPC code label...
  • Page 36: Adjustment

    TK-280 ADJUSTMENT Test Equipment Required for Alignment Test Equipment Major Specifications Standard Signal Generator Frequency Range 136 to 174MHz (SSG) Modulation Frequency modulation and external modulation. Output -127dBm/0.1µV to greater than -47dBm/1mV Power Meter Input Impedance 50Ω. Operation Frequency 136 to 174MHz or more.
  • Page 37 ADJUSTMENT • Panel tuning Repair Jig (Chassis) Use jig (part No.: A10-1383-14) for repairing the TK-280. The jig facilitates the voltage check and protects the module when the voltage on the flow side of the TX-RX unit is checked 2: RED (RX AF OUTPUT) during pepairs.
  • Page 38: Test Mode

    TK-280 ADJUSTMENT ■ Frequency and signalling Test Mode The set has been adjusted for the frequencies shown in the ■ Test mode operating features following table. When required. re-adjust them following the This transceiver has a test mode. To enter test mode, adjustment procedure to obtain the frequencies you want in press [A] key and turn power on.
  • Page 39 TK-280 ADJUSTMENT LCD display (Test mode) LCD display (Tuning mode) channel No. Signalling No. FREQ Adjustment item Adjustment (1~256) Panel Tuning Mode VHF-F1 K,K3,M Press [S], now in tuning mode. Use [2 B] button to write TEST Ch RX frequency (MHz)
  • Page 40 TK-280 ADJUSTMENT Common Section Measurement Adjustment Specifications/ Item Condition Remark Test equipment Unit Terminal Unit Parts Method 1. Setting 1) BATT terminal voltage:7.5V 2) SSG Standard modulation [Wide] MOD:1kHz, DEV:3kHz [Narrow] MOD:1kHz, DEV:1.5kHz 2. VCO lock [Panel Test Mode] voltage...
  • Page 41 TK-280 ADJUSTMENT [Panel Tuning Mode except when Panel TEST Mode is specified.] Measurement Adjustment Specifications/ Item Condition Remark Test equipment Unit Terminal Unit Parts Method 7. Max DEV 1) Adj item [MAX] Power meter Panel Panel Encoder 3.8kHz ±50Hz Adjust Adjust [∗∗∗]...
  • Page 42 TK-280 ADJUSTMENT [Panel Tuning Mode except when Panel TEST Mode is specified.] Measurement Adjustment Specifications/ Item Condition Remark Test equipment Unit Terminal Unit Parts Method 12.LTR 1) Adj item [FLTR] Power meter Panel Panel Encoder 1.0kHz ±0.1kHz Deviation Adjust [∗∗∗]...
  • Page 43 TK-280 ADJUSTMENT Receiver Section [Panel Tuning Mode except when Panel TEST Mode is specified.] Measurement Adjustment Specifications/ Item Condition Remark Test equipment Unit Terminal Unit Parts Method 1. Sensitivity 1) Adj item [SENS] Panel Panel Encoder Adjust for 14dB SINAD or Adjust Adjust [∗∗∗]...
  • Page 44: Terminal Function

    TK-280 TERMINAL FUNCTION CN No. Pin No. Name I/O Function CN No. Pin No. Name I/O Function TX-RX UNIT (X57-5740-XX): TX-RX section PTT signal output. Not use. Power input after passing through LCD driver chip select input. the fuse. Audio mute signal input.
  • Page 45: Pc Board Views

    TK-280 PC BOARD VIEW DISPLAY UNIT (X54-3210-XX) (-10) : K, K2, M (-11) : K3, K4 Component Side View DISPLAY UNIT (X54-3210-XX) X54-3210-XX (B/2) S301 S302 S303 J72-0517-12 LAMP LCD ASSY CN302 ∗ D301 X54-3210-XX (A/2) – J72-0517-12 Component side...
  • Page 46 TK-280 PC BOARD VIEW DISPLAY UNIT (X54-3210-XX) (-10) : K, K2, M (-11) : K3, K4 Foil Side View CN303 X54-3210-XX (B/2) J72-0517-12 DISPLAY UNIT (X54-3210-XX) D321 R300 R302 R304 CN301 CN300 R303 R305 R301 C302 R311 R312 Q300 R306...
  • Page 47 TK-280 PC BOARD VIEW DISPLAY UNIT (X54-3210-XX) (-10) : K, K2, M (-11) : K3, K4 Component Side + Foil Side View CN303 X54-3210-XX (B/2) S301 S302 S303 J72-0517-12 LAMP DISPLAY UNIT (X54-3210-XX) D321 R300 R302 R304 LCD ASSY CN301...
  • Page 48: Tx-Rx Unit (X57-5740-Xx)

    TK-280 PC BOARD VIEW PC BOARD VIEW TX-RX UNIT (X57-5740-XX) (-10) : K, K3, M (-11) : K2, K4 Component Side View TX-RX UNIT (X57-5740-XX) MONI R267 C244 LAMP C247 R271 IC100 C223 C224 X57-5740-XX R258 C101 J72-0613-02 C217 C237...
  • Page 49 TK-280 PC BOARD VIEW TX-RX UNIT (X57-5740-XX) (-10) : K, K3, M (-11) : K2, K4 Foil Side View TX-RX UNIT IC16 R100 (X57-5740-XX) C246 R114 R109 R304 C119 R116 R123 R305 C256 IC17 C136 R295 R253/R310 C120 X57-5740-XX CN10...
  • Page 50 TK-280 PC BOARD VIEW TX-RX UNIT (X57-5740-XX) TX-RX UNIT (X57-5740-XX) (-10) : K, K3, M (-11) : K2, K4 Component Side + Foil Side View IC16 R100 MONI R267 C244 C246 LAMP C247 IC100 R271 R114 R109 R304 C119 R116...
  • Page 51: Block Diagram

    TK-280 TK-280 BLOCK DIAGRAM...
  • Page 52: Level Diagram

    TK-280 LEVEL DIAGRAM...
  • Page 53 TK-280 KNB-16A/17A (Ni-Cd BATTERY) / KPG-36 (PROGRAMMING INTER- FACE CABLE) / KSC-19 (CHARGER) / KRA-14 (HELICAL ANTENNA) KNB-16A KNB-17A KPG-36 External View External View External View KNB-16A KNB-17A KSC-19 External View Circuit Diagram Circuit Diagram Discharge pin side Discharge pin side...
  • Page 54: Specifications

    TK-280 KMC-25 (SPEAKER MICROHONE) Circuit Diagram External View Specifications Microphone Impedance ......2kΩ Sensitivity ........ -65dB±4.0dB at 1kHz Speaker Impedance ......16Ω Input ........0.5W Maximum input ......1.5W Dimensions ........62W x 81 H x 29 D (mm) Weight (With plug cord) ....Approx. 0.17kg...
  • Page 55 KENWOOD ELECTRONICS FRANCE S.A. 13, Boulevard Ney, 75018 Paris, France KENWOOD ELECTRONICS TECHNOLOGIES(S) PTE LTD. KENWOOD ELECTRONICS U.K. LIMITED Sales Marketing Division 1 Ang Mo Kio Street 63, Singapore 569110 KENWOOD House, Dwight Road, Watford, Herst., WD1 8EB United Kingdom...