TTI Freequency TCB-770 Service Manual Download

Page: 8 / 40

Semiconductors and Function

3-1. Transistor

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Ref

No.

Description

Manufacturer

Function

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Q101

KTC3880S

KEC

Amplifier

Q102

KTK211 KEC

1’st

Mixer

Q103

KTK211 KEC

1’st

Mixer

Q104

KRC101S

KEC

Band1

Switching

Q105

KRC101S

KEC

Band2

Switching

Q121

KRC110S

KEC

Q122

KRC112S

KEC

RSSI

Level

Control

Q151

KTC3875S

KEC

Amplifier

Q152

KRC112S

KEC

FM AF Mute at AM Mode

Q153

KRC101S

KEC

FM AF Mute at AM Mode

Q154

KRC112S

KEC

RX AF Mute at TX Mode

Q161

KTC3880S

KEC

Amplifier

Q162

KTC3880S

KEC

Amplifier

Q163

KRA102S

KEC

B+

Q164

KTA1504S

KEC

Automatic

Noise

Level

Control

Q181

KTC3875S

KEC

RX RF Mute at TX Mode

Q182

KTC3875S

KEC

AGC

Q183

KTC3875S

KEC

AGC

Q201

KRC101S

KEC

Mute

Q202

KRC111S

KEC

Path

Q233

KTA1504S

KEC

Automatic

Level

Control

Q234

KTC3875S

KEC

Automatic

Level

Control

Q301

KTC3880S

KEC

VCO

Q302

KTC3880S

KEC

RX/TX

VCO

Buffer

Q303

KTC3880S

KEC

VCO

Buffer

Q305

KRC101S

KEC

VCO

Control

Q311

KRC101S

KEC

VCO

Band1

Switching

Q312

KRC101S

KEC

VCO

Band2

Switching

Q313

KRC101S

KEC

VCO

Band3

Switching

Q502

KRC111S

KEC

FM TX AF Mute at AM TX

Q701

KTC3880S

KEC

Doublers

Q702

KTC3880S

KEC

Pre-Amplifier

Q703

KTC1006

KEC

Driver

Amplifier

Q704

2SC2078

SANYO TX

Power

Amplifier

Q742

KTC3875S

KEC

TX RF Mute at RX Mode

Q801

KRC104S

KEC

CPU

Reset

Q802

KRC101S

KEC

CPU

RX/TX

Control

Q803

KRA101S

KEC

MIC

Lock

Control

Q911

KTA1658

KEC

Main

Regulator

Q912

KRA1504S

KEC

Main

Regulator

Q913

KRC112S

KEC

Main

Regulator

Control

Q914

KRC102S

KEC

Power

Low

Control

Q921

KTC3875S

KEC

8.2V

Regulator

Q923

KTC3875S

KEC

B+

Q924

KRA1504S

KEC

B+

Q931

KTC3875S

KEC

Main

Regulator[5.6V]

Q941

KRC111S

KEC

Mute

Summary of Contents for Freequency TCB-770

Page 1: ...SERVICE MANUAL MULTI CHANNEL AM FM TRANSCEIVER TCB 770 TTI Tech Downloaded from www cbradio nl ...

Page 2: ...N 4 DESCRIPTION OF FREQUENCY DETERMINING AND STABILIZING CIRCUIT 5 TEST EQUIPMENT SETUP AND ALIGNMENT INSTRUCTIONS SECTION 5 3 LED PCB 3 PART LIST SECTION 5 1 MAIN PCB 5 2 5 4 VOLUME PCB 5 5 MIC PCB FRONT PCB 4 MECHANICAL DISASSEMBLY SECTION 5 BOARD LAYOUT SECTION 6 BLOCK DIAGRAM SECTION 7 SCHEMATIC TABLE OF CONTENTS ...

Page 3: ...nge without prior notice T R A N S M I T T E R R E C E I V E R G E N E R A L 40 See the frequency band chart 26 96 MHz 27 99125 MHz F3E FM A3E AM PLL Synthersizer 0 002 10 to 55 C Plug in Type 13 2V DC 15 140 W x 186 L x 37 H 990 g Antenna Connector Duty cycle 10 4 Watts 13 8V DC AM from 85 to 95 FM 1 8KHz 0 2KHz 300Hz to 3000Hz 50ohms Unbalanced More than 36dBm AM Full Mod 1 6A Max Dual conversio...

Page 4: ...2 Basic Synthesis Scheme 4 3 Descriptions of Each Block 4 3 1 Introduction 4 3 2 Reference Frequency 4 3 3 VCO 4 3 4 Programmable Divider and its Control 4 3 5 Phase Detector and VCO Control 4 3 6 Transmitter Receiver Buffer AMP 4 3 7 Transmitter Doublers 4 3 8 Switching of Turning Capacitor in VCO 4 3 9 Receiver Local Oscillator Outputs 4 4 Frequency Stability 4 5 Description of other Circuits 4 ...

Page 5: ... 0 3 uV to 100 uV Sensitivity FM 20 dB SINAD under 1 0 uV RF Signal or less AM 10 dB S N under 1 0 uV RF Signal or less Intermediate Frequency 1st IF 10 695 MHz 2nd IF 455 KHz 1 2 Transmitter Carrier Power Conducted AM 1 W FM 4 W Current Drain 13 2 V Supply Voltage No Modulation 1 000 mA Max Modulation 1 400 mA Modulation Capabilities AM 90 FM 1 8 KHz Dev Spurious Radiation Less then 72 dBc Antenn...

Page 6: ...ver Audio Control With Power ON OFF Control Volume Squelch Control Volume RF Gain Control Volume MIC GAIN Control Volume CHANNEL UP DOWN Rotary Switch EMG Emergency Channel Select Key AM FM Select Key Scan Key Q CHANNEL UP Key Q CHANNEL DOWN Key z Accessorily Connectors Antenna Socket External Speaker Jack External Signal Meter Jack Microphone Condenser Microphone 2 2 Type of emission AM A3E FM F3...

Page 7: ...345 15 27 135 35 27 355 16 27 155 36 27 365 17 27 165 37 27 375 18 27 175 38 27 385 19 27 185 39 27 395 20 27 205 40 27 405 2 4 RF Power Output z AM 1 0 W z FM 4 0 W 2 5 DC Iinput Voltage and Current with 13 2V DC Input to Power AMP z Transmitter Power Amp Voltage 12 5 V Current 727 mA z Transmitter Driver Amp Voltage 12 5 V Current 120 mA 2 6 Receiver IF and Local Oscillator Frequencies z First I...

Page 8: ...EC AF Path Q233 KTA1504S KEC Automatic Level Control Q234 KTC3875S KEC Automatic Level Control Q301 KTC3880S KEC VCO Q302 KTC3880S KEC RX TX VCO Buffer Q303 KTC3880S KEC VCO Buffer Q305 KRC101S KEC TX VCO Control Q311 KRC101S KEC VCO Band1 Switching Q312 KRC101S KEC VCO Band2 Switching Q313 KRC101S KEC VCO Band3 Switching Q502 KRC111S KEC FM TX AF Mute at AM TX Q701 KTC3880S KEC TX Doublers Q702 K...

Page 9: ... at AM Mode 3 2 IC Ref No Description Manufacturer Function IC101 TK144889V TOKO IF IC IC102 KIA358F KEC AGC Squelch Control IC201 KIA7217AP KEC AF Power Amplifier IC301 LC7152NM SANYO PLL IC401 KIA4558F KEC FM TX AF IC801 TMP87PP21DF TOSHIBA CPU IC802 24WC02 ATMEL EEPROM 3 3 Manufacture Information z KEC KEC Co LTD z SANYO SANYO Semiconductor Co LTD z TOKO TOKO Inc z TOSHIBA Toshiba Semiconductor...

Page 10: ...hesis Scheme The crystal frequency 4 5MHz is divided by 1800 times to make 2 5KHz which is fed to one side of the phase detector The VCO output is divided by a programmable divider and fed to other side of the phase detector Pin 9 10 of IC301 Passing the phase detector output closes the feedback loop through an active low pass filter and using the output to control the VCO frequency through varica...

Page 11: ... 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: ...27 165 3294 16 47 5433 13 5825 18 27 175 3296 16 48 5435 13 5875 19 27 185 3298 16 49 5437 13 5925 20 27 205 3302 16 51 5441 13 6025 21 27 215 3304 16 52 5443 13 6075 22 27 225 3306 16 53 5445 13 6125 23 27 255 3312 16 56 5451 13 6275 24 27 235 3308 16 54 5447 13 6175 25 27 245 3310 16 55 5449 13 6225 26 27 265 3314 16 57 5453 13 6325 27 27 275 3316 16 58 5455 13 6375 28 27 285 3318 16 59 5457 13 ...

Page 13: ...ta Pin 12 PLL Enable Pin 13 of IC801 Each input signal to control the PLL IC is done with provide key input Pin 18 19 25 26 27 28 29 32 33 34 35 37 For each key input an internal code converts EEPROM appropriate control to the programmable divider for that channel Since the change transmit and receive and additional bit is required at Pin 8 of IC801 to allow the ROM to recognize the status TX or R...

Page 14: ... IF mixer section z SECOND MIXER The output of 10 24MHz oscillator circuit with X101 is injected into the IF IC IC101 internally Incoming IF signal and 10 24MHz signal are mixed inside the IF IC to extract 2 nd IF signal 455KHz FM audio Signals are recovered with the way of quadrature detector AM signals are recovered with envelope detector 4 4 Frequency Stability Let Fo Crystal oscillator frequen...

Page 15: ...r reading is changed 1W under LOW state The turning is adjustment so that the actual power is from 3 8W to 4 0W There are no other additional controls for adjusting the TX output power D Modulation Control Modulation of the RF is a process that begins with the audio picked up by the microphone FM The microphone input is fed to mic audio amplifier IC401 that drives modulation vricap diode D302 in t...

Page 16: ...ystal filter CF101 The first IF is again mixed with a second local oscillator of 10 24MHz With the 10 240MHz signal IC101 FM IF IC converts the incoming signals to generate 2 nd IF signal and recovered audio signals 2 nd IF is filtered by a razor sharp ceramic filter CF101 coupled The 455KHz signal from the 2 nd IF filter was amplified and limits internally After amplification the signals fed to t...

Page 17: ...n Adjuster Adjust for 1 RX VCO voltage Adj Channel Frequency 1CH 26 956 MHz Mic Receive Volume Optional Squelch Optional RF Gain Optional Mic Gain Optional DC voltmeter to VCO Test point Figure 1 L301 1 5 2 0 V DC 2 TX VCO voltage Adj Channel Frequency 1CH 26 956 MHz Mic Transmit No Mod Volume Optional Squelch Optional RF Gain Optional Mic Gain Optional DC voltmeter to VCO Test point Figure 1 L301...

Page 18: ...nel Frequency 19CH 26 956 MHz Function AM or FM Mode CB ANL Off DX Mic Transmit No Mod Volume Optional Squelch Optional RF Gain Optional MIC Gain Optional Connect dummy load and Frequency Counter through Coupler to RF Power Meter Connect RF Power Meter to EXT ANT connector on the set Figure 2 CT302 Be sure that the indication of the transmitter frequency is 27 185MHz 300 Hz on the Frequency Counte...

Page 19: ...o signal level to obtain by 1KHz deviation When you increase the audio signal by 20 dB the deviation should not exceed 2 0KHz deviation Figure 3 RV401 1 8KHz 2 0KHz 5 TX Signal Meter Adj Channel Frequency 19CH 27 185MHz MIC Transmit Function FM Mode CB ANL Off DX Volume Optional Squelch Optional RF Gain Optional MIC Gain Minimum Connected through Dummy load to RF Power Meter Connect RF Power to EX...

Page 20: ...SG until the audio output becomes about 10dB S N 2 FM Sensitivity Adj Channel Frequency 19CH 27 185MHz MIC Receive Function FM Mode CB ANL Off DX SSG 27 185MHz 1KHz 67dBm 1 5KHz Dev Volume Optional Squelch Minimum RF Gain Maximum Connect RF Signal Generator to EXT ANT Connector Connect AC Level Meter and Distortion Meter and SINAD Meter across EXT SPK jack with 8 ohm Dummy Load Figure 4 L109 Audio...

Page 21: ...DX SSG 27 185MHz 1KHz 62dBm 1 5KHz Dev Volume Optional Squelch Maximum RF Gain Maximum Connect RF Signal Generator to EXT ANT Connector Connect AC Level Meter and Distortion Meter and SINAD Meter across EXT SPK jack with 8 ohm Dummy Load Figure 4 RV572 Adjust for S 9 on the signal meter Figure 4 ...

Page 22: ... T 1608 PHILIPS SMD 5 R805 R806 R807 R811 R814 18 CHIP RESISTOR 100K 1 16W 5 T 1608 PHILIPS SMD 1 R804 19 CHIP RESISTOR 1M 1 16W 5 T 1608 PHILIPS SMD 1 R803 20 CHIP RESISTOR 2 2K 1 16W 5 T 1608 PHILIPS SMD 5 R832 R833 R834 R835 R836 21 CHIP RESISTOR 220K 1 16W 5 T 1608 PHILIPS SMD 1 R808 22 CHIP RESISTOR 47K 1 16W 5 T 1608 PHILIPS SMD 11 R812 R816 R831 R851 R852 R853 R854 R857 R859 R862 R864 23 CH...

Page 23: ...100K 1 16W 5 T 1608 PHILIPS SMD 9 R140 R142 R159 R186 R188 R202 R233 R309 R311 49 CHIP RESISTOR 2M 1 16W 5 T 1608 PHILIPS SMD 1 R405 ECO050422 02 ECO050715 02 50 CHIP RESISTOR 1 5K 1 16W 5 T 1608 PHILIPS SMD 2 R742 R924 51 CHIP RESISTOR 15K 1 16W 5 T 1608 PHILIPS SMD 3 R155 R166 R235 52 CHIP RESISTOR 150K 1 16W 5 T 1608 PHILIPS SMD 1 R701 53 CHIP RESISTOR 2 2 1 16W 5 T 1608 PHILIPS SMD 1 R711 53 C...

Page 24: ...235 C323 C412 C415 C501 C502 C503 C504 C506 C703 C704 C708 C713 C901 C902 C903 C911 C922 C924 C932 79 CHIP CERAMIC 0 1UF 1608 PHILIPS SAMSUNG SMD 23 C122 C123 C132 C134 C135 C137 C138 C168 C169 C180 C186 C205 C236 C308 C322 C325 C330 C401 C402 C405 C413 C571 C573 ECO050715 02 80 CHIP CERAMIC 1UF 1608 PHILIPS SAMSUNG SMD 2 C159 C961 81 CHIP CERAMIC 0 022UF 1608 PHILIPS SAMSUNG SMD 5 C166 C203 C214 ...

Page 25: ...50412 01 111 CHIP TRANSISTOR KRC102S SOT 23 KEC SMD 1 Q914 112 CHIP TRANSISTOR KRC110S SOT 23 KEC SMD 3 Q121 Q960 Q961 ECO050715 02 113 CHIP TRANSISTOR KRC111S SOT 23 KEC SMD 3 Q202 Q502 Q962 ECO050412 01 114 CHIP TRANSISTOR KRC112S SOT 23 KEC SMD 4 Q122 Q152 Q154 Q913 115 CHIP TRANSISTOR KTA1504S SOT 23 KEC SMD 4 Q164 Q233 Q912 Q924 116 CHIP TRANSISTOR KTC3875S SOT 23 KEC SMD 9 Q151 Q181 Q182 Q18...

Page 26: ...1 C960 149 ELECT CAPACITOR 47UF KR1 16V470MA 5X11 DONGXIANG MAN 5 C143 C185 C206 C233 C933 150 DISK 100P MAN 1 C735 151 DIP TRIMMER 20PF KCVN620 FOKITS MAN 1 CT301 ECO050325 04 152 TRANSFORMER CHOKE T1 FINE FINE MAN 1 T901 ECO050509 02 153 TRANSFORMER EI 24 MOD T2 FINE FINE MAN 1 T201 ECO050509 02 154 IFT COIL RF FREE TX 27MHz TX1 FINE FINE MAN 2 L701 L702 155 IFT COIL 37MHz TX TX2 FINE FINE MAN 1...

Page 27: ... Front case plastic 10 BEZEL ACRYL CLEAR Bonso 1 11 DOUBLE TAPE BEZEL 3M 0 16t ECO 050402 01 Hankyung 1 For Bezel 12 VOL KNOB ABS BLACK Bonso 2 For Rf On off 13 DUAL KNOB ABS BLACK Bonso 2 For Rf On off 14 CH KNOB ABS BLACK same as TCB880 Vol knob Bonso 1 For Channel 15 D SPRING SK5 0 2t Zn plating TTI 2 For Rf On off 16 KEY PAD SILICONE CLEAR PU coating ECO 050328 07 Hankyung 1 17 LCD BRACKET SPT...

Page 28: ...X shield can 2 44 Cu Tape 1 Cu 49 9 0 1t ECO 050328 05 Bonso 1 For TX shield can 1 45 Cu Tape 2 Cu 77 15 0 1t ECO 050328 05 Same as TCB880 Bonso 1 For TX shield can 1 ACCESSORY 1 MIC ASS Y same as TCB880 Hankyung 1 2 BRACKET SET Hankyung 1 3 STUD BOLT ABS M6 8L BLACK same as TCB880 Hankyung 2 4 BRACKET MIC SUS304 1 0t same as TCB880 Hankyung 1 5 PACKING RUBBER PACKING RUBBER same as TCB880 Hankyun...

Page 29: ... 1 51 x2 x2 x2 9 8 11 12 14 15 x3 7 13 x3 x4 34 31 x3 51 4 32 29 x2 30 3 25 2 35 29 33 29 42 41 36 40 39 38 37 51 54 50 x2 x3 x2 x3 53 x3 55 x3 x2 x2 x2 48 52 51 44 43 50 26 51 47 52 56 46 49 28 45 27 51 SECTION4 MECHANICAL DISASSEMBLY ...

Page 30: ...ca 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 SPC 0 75t Black SPC 0 75t Black EGI 1 0t SPC 1 6t Blacke 1 6t 1 6t ABS Black ABS Black SK5 0 2t Zn plating ABS Black BsBm Ni plating Acryl 0 16t ABS Black 0 16t Acryl Acryl Silicone PU coating SPTE 0 3t Acryl Acryl Silicone ABS BsBm NBR S...

Page 31: ...5 1 Main PCB Top side SECTION5 BOARD LAYOUT ...

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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TTI Freequency TCB-770, Service Manual

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