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144MHz FM TRANSCEIVER
TH-K2AT/K2E/K2ET
SERVICE MANUAL
© 2003-8 PRINTED IN JAPAN
B51-8658-00 (S) 836
Helical Antenna Helical Antenna
(T90-1018-25) (T90-1018-25)
Knob (ENC) Knob (ENC)
(K29-5159-03) (K29-5159-03)
Knob (VOL) Knob (VOL)
(K29-5150-03) (K29-5150-03)
Front glass Front glass
Knob (B10-2746-03) Knob (B10-2746-03)
(PTT/LAMP/MON) (PTT/LAMP/MON)
(K29-9274-03) (K29-9274-03)
Cap Cap
(SP/MIC/DC IN) (SP/MIC/DC IN)
(B09-0675-03) (B09-0675-03)
Cabinet assy Cabinet assy
(16key) (4key)
Key top (4key
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TH-K2AT/K2E/K2ET DISASSEMBLY FOR REPAIR How to remove the case assembly from the chassis c x 1. Remove two screws (z) holding the chassis. 2. Pull out two knobs (x) and remove two round nuts (c). x 3. Pull out the SP and MIC parts of the cap from jacks (v). c 4. Turn the unit over with the bottom of the chassis facing upwards, and remove the chassis (n) from the case assembly (b). 5. Remove the speaker lead (m) from the connector (CN2) of v the TX-RX PC board (TX-RX unit A/3). m b How to remove
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TH-K2AT/K2E/K2ET DISASSEMBLY FOR REPAIR 4. Apply the tips of soldering irons to all the four pins of the final Soldering the antenna terminal FET at the same time (c), heat them sufficiently, and remove 1. With the shield cover removed from the antenna terminal the final FET (v). (Two persons should be required to do this.) section, install two screws on the PC board and bring the PC board into contact with the chassis (z). 2. Solder the antenna terminal with a soldering iron (x). v c x z 5. Rem
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TH-K2AT/K2E/K2ET DISASSEMBLY FOR REPAIR (2)By pressing the LCD hardware fixture from the component Special care and attention required for assembly side of the TX-RX PCB, you must bent all 4 tabs of the LCD 1. Gluing to the key top (MIC element section) hardware fixture being visible from the foil side until the You must also glue on the speaker storage area and heap bases of each tabs are folded at least 45 degrees (Fig. 3). If the glue up until wealthy glued on the speaker storage area the be
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PTT LOW LAMP TH-K2AT/K2E/K2ET DISASSEMBLY FOR REPAIR 4. Packing (G53-1572-02) TX/BUSY lamp installation 6. Cautions for installing the chassis on the case assembly procedure (1) Verify that the packing (G53-1572-02) TX/BUSY lamp section (1)To assure waterproofing, install the packing in the chassis is has been past through the hole in the illumination guide groove as shown in Fig. 5. (z) section on the top of the case assembly. (Fig. 7) (2)Install the packing TX/BUSY lamp section on the chassis.
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TH-K2AT/K2E/K2ET CIRCUIT DESCRIPTION A tuning voltage corresponding to the desired signal is Frequency Configuration applied to each varicap through the BPF/APC terminal (pin 6) The frequency configuration is shown in Figure 1 and of the MPU (IC8) to tune to the receive frequency. Table 1. RX : 136.000~173.995MHz(K,K2,M,M2) ■ First Mixer 144.000~145.995MHz(E,E3) TX : 144.000~147.995MHz(K,K2) 450kHz The received signal passing through the band-pass filter 136.000~173.995MHz(M,M2) CF ANT 144.000~1
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TH-K2AT/K2E/K2ET CIRCUIT DESCRIPTION ■ IF Circuit FM IC and band-pass filter consisting of R125, R126, R135, The first IF signal (38.85 MHz) amplified by the IF amplifier (Q24) C173, C174. The noise component is rectified in the FM IC to and the second IF signal (38.4 MHz) generated by tripling the 12.8 produce a DC voltage, which is output from the N-REC terminal MHz reference oscillator frequency of the TCXO (X1) by Q23, are (pin 14) of the FM IC as squelch voltage. mixed in the FM IC to prod
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TH-K2AT/K2E/K2ET CIRCUIT DESCRIPTION Transmitter System The transmission/reception switching circuit consists of D10, L19, D12 and D13. These diodes are turned ON in transmit ■ Microphone Amplifier Circuit mode and OFF in receive mode to switch signals. The audio signal from the microphone passes through a Q2 Q9 high-pass filter (IC5) and enters a microphone amplifier (IC16). MIC IC5 IC16 Q1 RF AMP RF AMP The signal passes through a pre-emphasis circuit, limiter MIC HPF VCO amplifier and splatte
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TH-K2AT/K2E/K2ET CIRCUIT DESCRIPTION The APC voltage controls the gate voltage of Q11 and Q12, amplifying VCO output with an RF amplifier (Q6) and dividing and keeps transmission output stable. it with the PLL IC. The MPU detects power supply voltage and controls Q58 The PLL synthesizer with 5 kHz and 6.25 kHz step is by transmission power supply voltage and transmission power. configured by comparing phases of the reference frequency For example, if the power supply voltage during transmission,
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TH-K2AT/K2E/K2ET CIRCUIT DESCRIPTION Power Supply Circuit ■ Power Supply Switching Circuit The voltage supplied through the battery terminal or DC IN ■ Charging Circuit terminal is branched in the power supply switching circuit as When an external power supply is connected to the DC IN shown in Fig.10 and then supplied to the required components. terminal, the constant-current circuit consisting of Q33 and D31 provides a constant current of approx. 110 mA to the Ni- ■ Battery Type Recognition Ci
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TH-K2AT/K2E/K2ET CIRCUIT DESCRIPTION ■ Voltage Detection Circuit ■ LED Drive Circuit Various voltages are input to the A/D port of the MPU (IC8) The LCD and key illumination LEDs are lighted by controlling for processing. Q51 for the LCD and Q50 for keys according to the output Battery voltage is divided with resistors (R240, R241) and voltage from the AF/LAMP AVR (Q37). enters the BATT terminal (pin 52) of the MPU. The BUSY and TX illumination LEDs are lighted by controlling Battery voltage is
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TH-K2AT/K2E/K2ET CIRCUIT DESCRIPTION ■ Key and Encoder Input Circuit The POWER key is assigned to the interrupt port (pin 95) of Other keys composes a matrix and key presses are detected the MPU. by scanning them by software. The PTT key is assigned to the dedicated port (pins 13, 14) The encoder reads data using the interrupt port (pins 35 of the MPU. and 36) of the MPU. 16 key (K, K2, M, M2 and E3 types) IC8 MPU KIN0 KIN1 KIN2 KIN3 KIN4 KOUT0 KOUT1 KOUT2 KOUT3 PWRSW PTTI PTTE ENCB ENCA 95 14 1
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TH-K2AT/K2E/K2ET CIRCUIT DESCRIPTION ■ CTCSS/DCS ■ DTMF The encode signal is generated by the MPU (IC8) and output The DTMF signal is generated by the MPU (IC8) and is from the TONE terminal (pin 41) of the MPU. output from the DTMF/BEEP terminal (pin 40) of the MPU. The unwanted high-frequency components of the encode The DTMF signal is mixed with an audio signal at the input signal output from the MPU are removed with a low-pass filter, side of the AF amplifier (IC6), and is output as a monito
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TH-K2AT/K2E/K2ET SEMICONDUCTOR DATA MPU : 90522BPFFG139 (IC8) ■ Pin function Pin Pin Pin Pin I/O Function I/O Function No. Name No. Name 1 CLOCK O Common serial clock output 48 SQ I Noise voltage input for squelch (A/D) 2 DATA O Common serial data output 49 SM I RSSI voltage input for S-meter (A/D) 50 VOXIN I Microphone voltage input for VOX (A/D) 3 EEPDI I Data input from EEPROM 4 EEPCS O Chip select output to EEPROM 51 THERM I TX temperature compensation input(A/D) 52 BATT I Battery voltage in
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TH-K2AT/K2E/K2ET SEMICONDUCTOR DATA / COMPONENTS DESCRIPTION Pin Pin COMPONENTS DESCRIPTION I/O Function No. Name DC IN detection interrupt input ( ) ↓ TX-RX UNIT (X57-674X-XX) 98 DCDET I L:DC IN connected Ref. No. Use/Function Operation/Condition/Compatibility 99 RXLED O Busy LED output H:ON IC1 PLL IC 100 BSFT O Beat shift swiching output H:ON APC differential IC2 101 PLLEN O Serial enable output to PLL IC amplifier 102 PLLLD I Lock detection input from PL
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TH-K2AT/K2E/K2ET COMPONENTS DESCRIPTION Ref. No. Use/Function Operation/Condition/Compatibility Ref. No. Use/Function Operation/Condition/Compatibility Q33 operation Reverse current Q34 On when charging D33 Battery switch prevention Q35 DC IN detection H: DC IN detection AVR D34 Ni-MH temperature On when temperature detection is constant-voltage Q36 detection activated Reverse current D35 Battery AF amplifier/ prevention Q37 Lamp AVR Reverse current D36 DC IN Q37 operation On when the speaker ou
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TH-K2AT/K2E/K2ET PARTS LIST L: Scandinavia K: USA P: Canada ∗ New Parts. indicates safety critical components. Y: PX (Far East, Hawaii) T: England E: Europe Parts without Parts No. are not supplied. Y: AAFES (Europe) X: Australia M: Other Areas Les articles non mentionnes dans le Parts No. ne sont pas fournis. Teile ohne Parts No. werden nicht geliefert. TH-K2AT/K2E/K2ET (Y50-580X-XX) TX-RX UNIT (X57-674X-XX) New New Ref. No. Address Parts No. Description Destination Ref. No. Address Parts
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TH-K2AT/K2E/K2ET PARTS LIST TX-RX UNIT (X57-674X-XX) New New Ref. No. Address Parts No. Description Destination Ref. No. Address Parts No. Description Destination parts parts C33 C92-0002-05 CHIP-TAN 0.22UF 35WV C136 CC73HCH1H100D CHIP C 10PF D C34 C92-0714-05 TANTALUM 4.7UF 6.3WV C137 CC73HCH1H050C CHIP C 5.0PF C C35 C92-0001-05 CHIP-C 0.1UF 35WV C138 CK73HB1H102K CHIP C 1000PF K C37 CK73HB1H102K CHIP C 1000PF K C141,142 CK73HB1H102K CHIP C 1000PF K C38 CK73HB1C103K CHIP C 0.010UF K C145 CC73HC
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TH-K2AT/K2E/K2ET PARTS LIST TX-RX UNIT (X57-674X-XX) New New Ref. No. Address Parts No. Description Destination Ref. No. Address Parts No. Description Destination parts parts C230 CK73FB1C105K CHIP C 1.0UF K C359,360 CK73HB1A104K CHIP C 0.10UF K C231,232 CK73HB1H102K CHIP C 1000PF K C366 ∗ CC73GCH1H101G CHIP C 100PF G C235,236 CK73HB1C103K CHIP C 0.010UF K C500,501 CC73HCH1H1R5B CHIP C 1.5PF B C237 C92-0628-05 CHIP-TAN 10UF 10WV C502 CC73HCH1H030B CHIP C 3.0PF B C238-241 CK73HB1H102K CHIP C 1000
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TH-K2AT/K2E/K2ET PARTS LIST TX-RX UNIT (X57-674X-XX) New New Ref. No. Address Parts No. Description Destination Ref. No. Address Parts No. Description Destination parts parts L55 L41-1078-14 SMALL FIXED INDUCTOR R70-72 RK73EB2ER39K CHIP R 0.39 K 1/4W L56 ∗ L41-2278-14 SMALL FIXED INDUCTOR R74,75 RK73HH1J104D RESISTOR 100K D 1/16W L58 ∗ L41-8285-14 SMALL FIXED INDUCTOR R76-79 RK73HH1J154D RESISTOR 150K D 1/16W L63 L92-0140-05 FERRITE CHIP R80 RK73HB1J103J CHIP R 10K J 1/16W L64 L40-4795-85 SMALL
