Copyright 2011 by JVC KENWOOD Corporation. All While every precaution has been taken in the preparation rights reserved. of this manual, JVC KENWOOD Corporation assumes no No part of this manual may be reproduced, translated, responsibility for errors or omissions. Neither is any liability...
TH-K20A/K20E DISASSEMBLY FOR REPAIR 3. Removing the Rear Panel 1. Raise the rear panel on the chassis ( k ). Antenna terminal CLONE MODE Programming data can be transferred from one trans- Note: ceiver to another by connecting them via their SP/MIC con- •...
TH-K20A/K20E CIRCUIT DESCRIPTION 1. Frequency Confi guration The PLL circuit in the transmitter generates the neces- sary frequencies. The receiver utilizes double conversion. The first IF is 38.85MHz and the second IF is 450kHz. The fi rst Local os- cillator is supplied from the PLL circuit.
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TH-K20A/K20E CIRCUIT DESCRIPTION 2-3. IF Amplifi er Circuit 3. Transmitter System The fi rst IF signal is passed through a four-pole mono- 3-1. Microphone Amplifi er Circuit lithic crystal fi lter (XF200) to remove the adjacent channel The signal from microphone amplifi ed by IC301 and goes signal.
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TH-K20A/K20E CIRCUIT DESCRIPTION 4. Frequency Synthesizer Circuit Realign the transceiver after replacing the EEPROM. 4-1. Frequency Synthesizer The frequency synthesizer consists of the TCXO (X1), 6. Signaling Circuit VCO, PLL IC (IC1) and buffer amplifi ers. 6-1. Encode The TCXO generates 19.2MHz. The frequency stability is 5.0 ppm within the temperature range of –30 to +60°C.
TH-K20A/K20E SEMICONDUCTOR DATA MCU: R5F2L3ACCKEKA (TX-RX unit IC401) Pin No. Port Name Function [MONI] key switch input Pin No. Port Name Function MONI L: Active KEYIT Type detection Common serial clock output KEYIS Type detection DATA Common serial data output...
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TH-K20A/K20E SEMICONDUCTOR DATA PLL IC: MB15E03SL-E1 (TX-RX unit IC1) D/A Converter IC: R2A20178NP (TX-RX unit IC300) Pin No. Port Name Function Programmable reference divider Pin No. Port Name Function OSCIN input Vin2 FROM AF fi lter signal input OSCOUT Oscillator output Power supply voltage (5.0V)
TH-K20A/K20E COMPONENTS DESCRIPTION TX-RX unit (X57-821X-XX) Ref. No. Use/Function Operation/Condition/Compatibility Power supply Ref. No. Use/Function Operation/Condition/Compatibility Q304 Active ON (5MSC: L) (5MS) switch PLL system Frequency control Speaker mute Q305 for AF signal line Active ON 2nd mixer, IF amplifi er, FM...
TH-K20A/K20E PARTS LIST 2 2 0 CC45 Color* 010 = 1pF 0 = 22pF 1 = Type ... ceramic, electrolytic, etc. 4 = Voltage rating 100 = 10pF 2 = Shape ... round, square, etc. 5 = Value 101 = 100pF Multiplier 3 = Temp.
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CC73HCH1H050C CHIP C 5.0PF CC73GCH1H220J CHIP C 22PF X57-8210-12 TX-RX UNIT (FOR SERVICE) C101 CC73HCH1H220J CHIP C 22PF X57-8210-21 TX-RX UNIT (FOR SERVICE) X57-8212-72 TX-RX UNIT (FOR SERVICE) C102 CK73HB1H102K CHIP C 1000PF M: TH-K20A(M) K : TH-K20A(K) E : TH-K20E(E)
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CHIP C 1000PF C231 CC73HCH1H050C CHIP C 5.0PF C351,352 CK73HB1H102K CHIP C 1000PF C232 CC73HCH1H101J CHIP C 100PF C353 CK73HB1C473K CHIP C 0.047UF C233 CK73HB1H102K CHIP C 1000PF C354 CK73HB1H102K CHIP C 1000PF M: TH-K20A(M) K : TH-K20A(K) E : TH-K20E(E)
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SMALL FIXED INDUCTOR (10UH) RK73HB1J100J CHIP R 1/16W L40-1285-71 SMALL FIXED INDUCTOR (120NH) M: TH-K20A(M) If a part reference number is listed in a shaded box, that part does not come with the PCB. K : TH-K20A(K) E : TH-K20E(E)
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RK73HB1J104J CHIP R 100K 1/16W R372 RK73HB1J473J CHIP R 1/16W R241 RK73HB1J184J CHIP R 180K 1/16W R374 RK73HB1J103J CHIP R 1/16W R243 RK73HB1J105J CHIP R 1.0M 1/16W R376 RK73HB1J000J CHIP R 1/16W M: TH-K20A(M) K : TH-K20A(K) E : TH-K20E(E)
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RB521S-30 DIODE D304 RB521S-30 DIODE D305 DZ2S068(M) ZENER DIODE D401 DZ2S036(0) ZENER DIODE M: TH-K20A(M) If a part reference number is listed in a shaded box, that part does not come with the PCB. K : TH-K20A(K) E : TH-K20E(E)
TH-K20A/K20E EXPLODED VIEW Cx13 S418 MIC300 J301 J300 VR300 TX-RX unit S419 A : N09-2438-05 B : N80-2606-43 C : N83-2005-48 Parts with the exploded numbers larger than 700 are not supplied. If a part reference number is listed in a box on the exploded view of the PCB, that part does not come with the PCB.
56 HELICAL ANTENNA (T90-1018-35): M 61 CHARGER (W08-1249-35) 37 PACKING FIXTURE (H12-4324-02): K 42 Belt clip (J29-0756-05) 41 ITEM CARTON CASE M: TH-K20A(M) (H52-2486-02): K K: TH-K20A(K) E: TH-K20E(E) Parts with the exploded numbers larger than 700 are not supplied.
TH-K20A/K20E ADJUSTMENT Note: Required Test Equipment • When performing the TH-K20 adjustment, a personal 1. Stabilized Power Supply computer, programming interface cable (KPG-22A/22U), 1) The supply voltage can be changed between 3V and 16V tuning cable (E30-3216-05) and tuning software (MCP-5T) and the current is 3A or more.
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TH-K20A/K20E ADJUSTMENT Frequency and Signaling Preparations for Tuning the Transceiver The transceiver has been adjusted for the frequencies Before attempting to tune the transceiver, connect the shown in the following table. When required, re-adjust them unit to a suitable power supply.
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TH-K20A/K20E ADJUSTMENT Common Section Measurement Adjustment Item Condition Specifi cations / Remarks Test- Unit Terminal Unit Parts Method equipment 1. Setting 1) BATT terminal voltage: 7.5V 2) SSG standard modulation [Wide] MOD: 1kHz, DEV: 3kHz [Narrow] MOD: 1kHz, DEV: 1.5kHz 2.
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TH-K20A/K20E ADJUSTMENT Measurement Adjustment Item Condition Specifi cations / Remarks Test- Unit Terminal Unit Parts Method equipment 7. Battery 1) BATT terminal voltage: 7.1V Power TX-RX ANT Check Segment display: 4 dots Detection PTT: ON meter BATT Check TX Power: Low...
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TH-K20A/K20E TH-K20A/K20E PC BOARD PC BOARD TX-RX UNIT (X57-821X-XX) 0-11: K 0-20: M 2-71: E TX-RX UNIT (X57-821X-XX) 0-11: K 0-20: M 2-71: E Component side view (J79-0325-09) Component side view (J79-0325-09) J79-0325-09 D415 R366 R443 D419 D418 C372 MIC300...
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TH-K20A/K20E TH-K20A/K20E PC BOARD PC BOARD TX-RX UNIT (X57-821X-XX) 0-11: K 0-20: M 2-71: E TX-RX UNIT (X57-821X-XX) 0-11: K 0-20: M 2-71: E Foil side view (J79-0325-09) Foil side view (J79-0325-09) S417 S418 MONI C108 C105 R107 R444 L104...