TTI TCB-770 Service Manual
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TTI TCB-770 Service Manual

Multi channel am/fm transceiver
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SERVICE
MANUAL
MULTI CHANNEL AM/FM TRANSCEIVER
TCB-770
TTI Tech

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Summary of Contents for TTI TCB-770

  • Page 1 Downloaded from www.cbradio.nl SERVICE MANUAL MULTI CHANNEL AM/FM TRANSCEIVER TCB-770 TTI Tech...
  • Page 2 TABLE OF CONTENTS SECTION SPECIFICATIONS SECTION CIRCUIT DESCRIPTION GENERAL TECHNICAL DESCRIPTION SEMICONDUCTORS AND FUNCTION DESCRIPTION OF FREQUENCY DETERMINING AND STABILIZING CIRCUIT TEST EQUIPMENT SETUP AND ALIGNMENT INSTRUCTIONS SECTION PART LIST SECTION MECHANICAL DISASSEMBLY SECTION BOARD LAYOUT MAIN PCB FRONT PCB LED PCB VOLUME PCB MIC PCB...
  • Page 3 SECTION1 SPECIFICATIONS Channel 40 (See the frequency band chart) Frequency Range 26.96 MHz ~ 27.99125 MHz Operating mode F3E (FM), A3E (AM) Frequency Control PLL Synthersizer Frequency Tolerance 0.002% Operating Temperature Range -10 to + 55 C Microphone Plug-in Type Input Voltage 13.2V DC ±...

  • Page 4: Table Of Contents

    SECTION2 CIRCUIT DESCRIPTION ------------ Contents ------------- General 1-1. Receiver 1.2. Transmitter Technical Description 2-1. General 2-2. Type of emission 2-3. Frequency Table 2-4. RF Power Output 2-5. DC input Voltage and Current with 13.2V DC Input to Power AMP 2-6. Receiver IF and Local Oscillator Frequencies Semiconductors and Function Description of Frequency Determining and Stabilizing Circuit...

  • Page 5: General

    General 1-1. Receiver ① Display : 40 Channels and other functions indication ② Frequency Range : 26.965 to 27.405 [MHz] ③ Frequency Response : 300 to 2,500 [Hz] ④ Power Source : 13.2 [V] DC ⑤ Audio Output Load : 8 [OHM] ⑥...
  • Page 6 Technical Description 2-1. General Model CB-770 is an mobile type AM/FM radio transceiver for use of the Citizen Radio Service. Front Panel Controls ① LCD (Cannel and RX/TX Signal Level Indicator). ② Receiver Audio Control (With Power ON/OFF Control) Volume ③...
  • Page 7 2-3. Frequency Table Channel Frequency (MHz) Channel Frequency (MHz) 26.965 27.215 26.975 27.225 26.985 27.235 27.005 27.245 27.015 27.255 27.025 27.265 27.035 27.275 27.055 27.285 27.065 27.295 27.075 27.305 27.085 27.315 27.105 27.325 27.115 27.335 27.125 27.345 27.135 27.355 27.155 27.365 27.165 27.375...
  • Page 8 Semiconductors and Function 3-1. Transistor -------------------------------------------------------------------------------------------------------------------------------------------- Ref No. Description Manufacturer Function -------------------------------------------------------------------------------------------------------------------------------------------- Q101 KTC3880S RX Amplifier Q102 KTK211 1’st Mixer Q103 KTK211 1’st Mixer Q104 KRC101S RX Band1 Switching Q105 KRC101S RX Band2 Switching Q121 KRC110S Q122 KRC112S RX RSSI Level Control Q151 KTC3875S RX FM AF Amplifier...
  • Page 9 Q951 KTA1241 Back Light LED Control Q952 KTA1241 Back Light LED Control Q953 KRC101S Back Light LED Control Q954 KRC101S Back Light LED Control Q961 KRC110S TX AF Mute at RX Mode Q962 KRC111S MIC AF Path at AM Mode 3-2.

  • Page 10: Receiver

    Description of Frequency Determining and Stabilizing Circuit 4-1. Introduction The Frequencies for transmitter and receiver first local frequencies are all derived from a signal 4.5MHz crystal by means of a phase locked loop(PLL). The first local oscillator frequencies are 16.270MHz(CH1) to 16.710MHz(CH40). The second local frequency is fixed at 10.240MHz to generate second IF 455KHz.
  • Page 11 Transmit CH 1 , 13.4825 MHz 26.965 MHz Transmit CH 40 , 13.7025 MHz 27.405 MHz Since all frequencies are obtained from the crystal controlled PLL oscillator, all outputs are coherent with the crystal oscillator frequency and matching the sample percentage accuracy. Note that the reference frequency of 5KHz(receiver) and 2.5KHz(transmitter) is obtained by dividing the 4.5MHz by 900 times and 1800 times See Table 1 for transmitter/receiver mode VCO frequencies.
  • Page 12 Program Data & Frequency[Table 1] Frequency Channel [MHz] Fvco Fvco 26.965 3254 16.27 5393 13.4825 26.975 3256 16.28 13.4875 5395 26.985 3258 16.29 13.4925 5397 27.005 3262 16.31 13.5025 5401 27.015 3264 16.32 13.5075 5403 27.025 3266 16.33 13.5125 5405 27.035 3268 16.34...

  • Page 13: Introduction

    4-3. Descriptions of Each Block 4-3-1. Introduction The synthesizer is implemented with the following components; PLL IC (IC301) X-TAL (X301) VCO, VARICAP DIODE (D301) IC1301 is CMOS LSI that includes most of PLL block. The Q301, L301, C311, C312, C313, C314, variable capacitance diode D301 are clapping oscillator circuit to operate as a VCO of the IC301.

  • Page 14: Transmitter Doublers

    4-3-7. Transmitter Doublers The output signal of Q302, L302 goes to an amplifier with tuning circuit Q701, L701, L702 which doubles incoming 13MHz signals. 4-3-8. Switching of Turning Capacitor in VCO The VCO circuit must tune with a wide range of frequencies 13.4825MHz ~ 13.7025MHz for transmitter and 16.27MHz ~16.71MHz for receiver.

  • Page 15: Description Of Other Circuits

    4-5. Description of other Circuits 4-5-1. Transmitter RF Amplification RF carrier frequencies are obtained at the output of doublers amplifier Q701 and turning IFT coil L701, L702. The input of VCO frequencies 13MHz is selected at the doublers output, which creates the necessary 27MHz.

  • Page 16: Receiver

    4-5-2. Receiver Overload protection is provided to receiver’s semiconductors by diode D101. These diodes have a little effect on the incoming signal from another CB station; they protect the receiver from stray transmitter energy. In the receiver mode of operation, Q923 transistor is turned on. Also bias voltage is applied to Q101, Q102, Q103, Q106.

  • Page 17: General Section

    Test Equipment Setup and Alignment Instructions General Section 5-1-1 Test Equipment Required • DC power supply(13.2V/3A) • DC Voltmeter or Oscilloscope • RF attenuator (30dB) 5-1-2 Alignment Procedure Step Setting Connection Adjuster Adjust for RX VCO voltage Adj. DC voltmeter to VCO L301 1.5~2.0 V DC Channel &...

  • Page 18: Transmitter Section

    Transmitter Section 5-2-1 Test Equipment Required • RF Power Meter • DC power supply(13.2V/3A) • 50 ohms load (non-inductive) • Spectrum analyzer • RF attenuator (30dB) • Frequency counter • Oscilloscope • Coupler • Audio generator • Modulation meter 5-2-2 Alignment Procedure Step Setting...
  • Page 19 FM Deviation Adj. Connection the audio RV401 1.8KHz ~ Channel & Frequency : generator (set to 1 KHz)to the 2.0KHz 19CH, 27.185MHz microphone. MIC : Transmit Connect the modulation meter Function : FM Mode through the RF attenuator to CB/ANL Off/DX the ANT Connector.

  • Page 20: Receiver Section

    Receiver Section 5-3-1 Test Equipment Required • Standard Signal Generator(SSG) • DC power supply(13.8V/3A) • AC Level Meter • Distortion Meter • Oscilloscope • SINAD Meter • 8 ohm Dummy Load 5-3-2 Alignment Procedure Step Setting Connection Adjuster Adjust for AM Sensitivity Adj.
  • Page 21 RX Signal Meter Adj. Connect RF Signal Generator RV572 Adjust for S-9 Channel & Frequency : to EXT-ANT Connector. on the signal 19CH, 27.185MHz Connect AC Level Meter and meter. MIC : Receive Distortion Meter and SINAD Function : FM Mode Meter across EXT SPK jack CB/ANL Off/DX with 8 ohm Dummy...
  • Page 22 IWS-164-BXWF ITSWELL D959, D965, D966 ECO050511-02 IC EEPROM AT24C02 (SOP-8) ATMEL IC802 IC CPU TMP87PP21DF TOSHIBA IC801 LCD DISPLAY SDM8A2299A FOR TCB-770 SANTECH LCD801 SW801, SW802, SW806, SW807, SW TACT SKTS-1102A SEKWANG SEKWANG SW808 RESONATOR 4.0MHz ZTA4.00MG D.TRON D.TRON X801...
  • Page 23 NAME & DESCRIPTION VENDOE CODE Q'ty Location NO ITEM MAKER VENDOR ASS'Y REMARKS MAIN BODY ASS'Y CONNECTOR CH-239(A)-M SAMWOO J701 ECO050511-02 TRANSISTOR KTA1658 Q911 TRANSISTOR 2SC2078 SANYO YANG WON Q704 KIA7217AP IC201 POWER CODE 2PIN PLUG ASS'Y FINE FINE J900 MAIN PCB AUTO ASS'Y PCB MAIN FR-4 / R-1...
  • Page 24 NAME & DESCRIPTION VENDOE CODE Q'ty Location NO ITEM MAKER VENDOR ASS'Y REMARKS CHIP RESISTOR 1/16W 5% T 1608 PHILIPS R184, R705, R913 R101, R105, R106, R165, R181, CHIP RESISTOR 1/16W 5% T 1608 PHILIPS R236, R931 R138, R223, R406, R704, R915, ECO050412-01 CHIP RESISTOR 4.7K...
  • Page 25 NAME & DESCRIPTION VENDOE CODE Q'ty Location NO ITEM MAKER VENDOR ASS'Y REMARKS C714, C715, C723, C725, C726, CHIP CERAMIC 330PF 1608 PHILIPS/SAMSUNG C729 CHIP CERAMIC 39PF 1608 PHILIPS/SAMSUNG C705 C103, C105, C107, C182, C328, CHIP CERAMIC 47PF 1608 PHILIPS/SAMSUNG C720, C722 CHIP CERAMIC 470PF...
  • Page 26 NAME & DESCRIPTION VENDOE CODE Q'ty Location NO ITEM MAKER VENDOR ASS'Y REMARKS 131 FILM RESISTOR 1/2W 5% ST MINI R953, R954 ECO050418-03 132 FILM RESISTOR 4.7K 1/2W 5% ST MINI R713 133 FILM RESISTOR 5% ST MINI R951, R952 ECO050418-03 134 METAL OXID RESISTOR 5% ST BULK...
  • Page 27 NAME & DESCRIPTION VENDOE CODE Q'ty Location NO ITEM MAKER VENDOR ASS'Y REMARKS 178 CRYSTAL 4.50MHZ 12PF:30PPM HC-49U D.TRON D.TRON X301 179 FILTER CRYSTAL 10L08A 10.695MHZ 49/T-3L D.TRON D.TRON XF101 180 FILTER CERAMIC LT455HTW D.TRON D.TRON CF101 ECO050525-02 181 JACK MINI SKJS-206 SEKWANG SEKWANG...
  • Page 28 NAME & DESCRIPTION VENDOE CODE Q'ty Location NO ITEM MAKER VENDOR ASS'Y REMARKS SCREW Mach(+) 3*8L-TAPTITE, Black, BH Bonso Main PCB + Main body mounting same as TCB880 / same as item 6. M3, SS41 same as TCB880 Bonso TR mounting SPRING WASHER same as TCB880 Bonso...
  • Page 29 SECTION4 MECHANICAL DISASSEMBLY 14 15...
  • Page 30 PART NAME DESCRIPTION REMARK Upper cover SPC 0.75t, Black Bottom cover SPC 0.75t, Black Main body EGI, 1.0t Bracket(Set) SPC 1.6t, Blacke Key PCB 1.6t Main PCB 1.6t Ch knob ABS, Black Vol knob ABS, Black Nut for Mic connector Washer for Mic connector D-Spring SK5, 0.2t, Zn plating...
  • Page 31 SECTION5 BOARD LAYOUT 5-1 Main PCB (Top side)
  • Page 32 Main PCB (Bottom side)
  • Page 33 5-2 Front PCB (Top side)
  • Page 34 Front PCB (Bottom side)
  • Page 35 5-3 LED PCB (Top side)
  • Page 36 LED PCB (Bottom side)
  • Page 37 5-4 Volume PCB...
  • Page 38 5-5 MIC PCB...
  • Page 39 SECTION6 BLOCK DIAGRAM...
  • Page 40 SECTION7 SCHEMATIC...

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