Icom IC-446S Service Manual Download Page 20

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R87

C72

C59

Q23

IC9

IC3

Q10

R58

R88

R86

C21

C47

R54

C44

R106

C82

R112

C86

IC1

TEST

B5420B

R68

R81

R72

C61

C46

R63

C45

R79

C87

R97

R99

C85

C99

R30

R39

C73

R40

R64

R53

C24

C98

C93

R52

R51

C83

Q12

Q29

R32

R35

C28

C91

C10

R14

C51

R62

R103

R101

R117

R105

R203

R108

R100

R96

R57

C26

R34

C40

R95

C11

R33

C27

C29

IC2

R59

R66

R65

R70

R71

R67

C92

C94

R94

C56

C54

R69

SHIFT

DATA

STB

SQL

SENS

PSC

BATT

MOD

T+3

VOL

R+3

GND

to RF unit J2

•

BOTTOM VIEW

Summary of Contents for IC-446S

Page 1: ...SERVICE MANUAL PMR446 FM TRANSCEIVER ...

Page 2: ...O M2x6 ZK IC 446S Chassis 10 pieces Addresses are provided on the inside back cover for your convenience 1 Make sure a problem is internal before disassembling the transceiver 2 DO NOT open the transceiver until the transceiver is disconnected from its power source 3 DO NOT force any of the variable components Turn them slowly and smoothly 4 DO NOT short any circuits or electronic parts An insulat...

Page 3: ... SUPPLY CIRCUITS 4 3 4 5 PORT ALLOCATIONS 4 3 SECTION 5 ADJUSTMENT PROCEDURES 5 1 PREPARATION 5 1 5 2 PLL AND TRANSMITTER ADJUSTMENTS 5 2 5 3 RECEIVER ADJUSTMENT 5 3 SECTION 6 PARTS LIST SECTION 7 MECHANICAL PARTS AND DISASSEMBLY SECTION 8 SEMI CONDUCTOR INFORMATION SECTION 9 BOARD LAYOUTS 9 1 MAIN UNIT 9 1 9 2 RF UNIT 9 3 SECTION 10 BLOCK DIAGRAM SECTION 11 VOLTAGE DIAGRAM 11 1 MAIN UNIT 11 1 11 ...

Page 4: ...ving system Double conversion superheterodyne Intermediate frequency 1st 21 7 MHz 2nd 450 kHz Sensitivity 12 dB SINAD Less than 0 25 µV 12 dBµV Adjcent chnnel selectivity 55 dB Spurious response 65 dB Intermoduration 60 dB Audio output power 100 mW at 10 distortion at 4 5 V DC with an 8 Ω load External SP connector 2 conductor 3 5 d mm 1 8 8 Ω CHANNEL FREQUENCY LIST CTCSS FREQUENCY LIST SECTION 1 ...

Page 5: ...amplifier IC9 NJM2070M EEPROM IC3 AT24C02N CPU IC1 µPD753036GK 3 Regurator IC6 S 81230SG TOP VIEW BOTTOM VIEW 1st mixer Q2 3SK284 Reference oscilletor X1 CR 669 21 25MHz PLL IC IC1 µPD3140GS TOP VIEW BOTTOM VIEW VCO circuit FM IF IC IC2 TA31136FN 1st IF filter FI2 FL 297 1st IF amplifier Q1 2SC4215 2nd IF filter FI3 CFWN450G RF amplifier Q3 2SC4226 ...

Page 6: ...EL 1 Unscrew 1 screw A and 4 screws B 2 Remove the rear panel in the direction of the arrow REMOVING THE RF UNIT 1 Remove 1 knob C and unscrew 1 nut D 2 Then remove the RF unit REMOVING THE MAIN UNIT 1 Unscrew 2 screws E 2 Remove the PTT rubber F 3 Unsolder 2 points G and remove the MAIN unit ...

Page 7: ...en applied to the 2nd mixer circuit 4 1 4 2ND MIXER AND DEMODULATOR CIRCUITS RF UNIT The 2nd mixer circuit converts the 1st IF signal into a 2nd IF signal A double conversion superheterodyne system which converts receive signals twice improves the image rejection ratio and obtains stable receiver gain The 1st IF signal from the IF amplifier Q1 is applied to the 2nd mixer section in the FM IF IC IC...

Page 8: ...rcuit modulates the VCO oscillating signal RF signal using the microphone AF signals The filtered audio signals from the MAIN unit are passed through the deviation adjustment pot R50 and are then applied to the modulation circuit D4 D5 to modulate trans mit signals at the VCO circuit Q6 The modulated signal is applied to the drive amplifier circuit 4 2 3 DRIVE POWER AMPLIFIER CIRCUITS RF UNIT The ...

Page 9: ...EEPROM IC3 Outputs data signals to the EEPROM IC3 Output port for power save function applied to VCO regurator circuit RF unit Q13 Q14 D8 D9 Outputs the R 3 regulator control sig nal Q25 D4 Outputs the T 3 regulator control sig nal Q27 Q28 Q101 D5 Outputs control signal for LCD back light Low While LCD backlight is ON Outputs internal microphone control signal High While internal PTT switch is pus...

Page 10: ... millivoltmeter External speaker Attenuator GRADE AND RANGE Frequency range 300 3000 Hz Measuring range 1 500 mV Frequency range 0 1 600 MHz Output level 0 1 µV 32 mV 127 to 17 dBm Frequency range DC 20 MHz Measuring range 0 01 10 V Measuring range 10 mV 10 V Input impedance 8 Ω Capacity 300 mW or more Power attenuation 30 or 40 dB Capacity 1 W or more ENTERING THE ADJUSTMENT MODE q Turn the trans...

Page 11: ...tor to the MIC jack and set as 1 kHz 100 mV rms Set an FM deviation meter as HPF OFF LPF 20 kHz or 15 kHz De emphasis OFF Detector P P 2 Transmitting Set group No OFF Set an audio generator output level until the deviation is 1 75 kHz Transmitting Top panel RF RF Loosely couple a fre quency counter to the antenna Connect an RF power meter to the RF test port J1 Connect an FM devia tion meter to th...

Page 12: ... UNIT LOCATION Audio signal disappears 1 2 Operating channel Ch 04 Connect an SSG to J1 on the RF unit and set as Frequency 446 04375 MHz Level 0 14 µV 124 dBm Modulation OFF Receiving Set an SSG as Level OFF Receiving Front panel Internal speaker Push and hold MODE and DOWN keys for 1 sec Verify ...

Page 13: ...ERJ3GEYJ 104 V 100 kΩ R63 7030003530 S RESISTOR ERJ3GEYJ 562 V 5 6 kΩ R64 7030003590 S RESISTOR ERJ3GEYJ 183 V 18 kΩ R65 7030003590 S RESISTOR ERJ3GEYJ 183 V 18 kΩ R66 7030003590 S RESISTOR ERJ3GEYJ 183 V 18 kΩ R67 7030003590 S RESISTOR ERJ3GEYJ 183 V 18 kΩ R68 7030003590 S RESISTOR ERJ3GEYJ 183 V 18 kΩ R69 7030003590 S RESISTOR ERJ3GEYJ 183 V 18 kΩ R70 7030003660 S RESISTOR ERJ3GEYJ 683 V 68 kΩ R...

Page 14: ...0003620 S RESISTOR ERJ3GEYJ 333 V 33 kΩ RF UNIT MAIN UNIT S Surface mount C34 4030006880 S CERAMIC C1608 JB 1H 472K T A C35 4030011600 S CERAMIC C1608 JB 1C 104KT N C36 4030006860 S CERAMIC C1608 JB 1H 102K T A C40 4030011600 S CERAMIC C1608 JB 1C 104KT N C42 4030006900 S CERAMIC C1608 JB 1E 103K T A C44 4030011600 S CERAMIC C1608 JB 1C 104KT N C45 4030009650 S CERAMIC C1608 CH 1H 240J T A C46 403...

Page 15: ...IC C1608 JB 1H 471K T A C30 4030006980 S CERAMIC C1608 CH 1H 070D T A C31 4030006980 S CERAMIC C1608 CH 1H 070D T A C32 4030006970 S CERAMIC C1608 CH 1H 060D T A C35 4030006860 S CERAMIC C1608 JB 1H 102K T A C36 4030006990 S CERAMIC C1608 CH 1H 080D T A C42 4030007010 S CERAMIC C1608 CH 1H 100D T A C43 4030007040 S CERAMIC C1608 CH 1H 180J T A C44 4030007060 S CERAMIC C1608 CH 1H 270J T A C46 4030...

Page 16: ...930045220 2045 BATT seal 1 MP14 8930046280 2045 ANT termainal 1 MP15 8930045350 2045 A terminal 1 MP16 8930045360 2045 B terminal 1 MP17 8930045370 2045 C terminal 2 MP19 8930045740 2045 sheet 1 MP20 8830001370 2045 VR nut 1 MP22 8930045750 Seal O ring X 1 MP23 8830000110 Nut M4 1 MP24 8810009560 Screw PH BO 2x6 ZK BT 4 MP25 8810008640 Screw FH BO 2x4 NI ZU BT 2 MP27 8830001390 2045 insert nut 1 M...

Page 17: ...T RF RF UNIT MP1 C SP1 C MP10 C MP12 C EP1 M DS2 M MP7 C MP5 C MAIN unit MP20 C MP25 C MP4 RF MP14 C MP17 C MP2 RF MP16 C MP23 C MP5 RF MP11 C MP13 C MP4 C MP2 C MP15 C MP25 C MP9 C MP8 C RF unit MP24 C MP30 C MP24 C MP22 C EP1 C MP19 C MP3 C MP1 RF ...

Page 18: ...bol K1 3SK284 Symbol U1 2SC4215 O Symbol QO 2SC4226 T2 R25 Symbol R25 2SC4228 T2 R44 Symbol R44 2SC5006 T1 Symbol 24 2SA1586 GR Symbol SG 2SB798 T2 DK Symbol DK 2SC3356 R24 T2B Symbol R24 2SC4081 T107S Symbol BS DTA144EUA T106 Symbol 16 B E C B E C B E C B E C E C B E C B E C B E C B E C B B E C S D G B E C E C B E C B E C B E1 B1 C2 C1 B2 E2 E1 B1 B2 C1 E2 C2 E C B E B C E D S G2 G1 S D S G 1SS35...

Page 19: ... C74 R49 R200 R201 R114 R115 R119 R204 W3 R98 C53 C60 C81 R74 R76 C63 R23 R80 R78 C88 W7 C90 C62 R102 R12 C35 C34 R10 C25 C3 R9 R31 R202 R118 R110 R45 R36 C36 C31 R42 R41 C32 R38 R46 C7 R13 C4 C79 R50 C5 R43 R37 C89 C65 R77 C57 IC6 IC5 C55 Q14 Q27 DS2 Q101 Q11 D101 D5 DS1 Q28 D2 C48 C18 C52 C17 C8 Q7 Q3 Q6 MC1 C80 Q25 D4 C67 Q18 C64 ...

Page 20: ...9 C85 C99 R2 R30 C1 R39 C73 R40 R64 W2 R5 R53 C24 C98 C93 R52 R51 C83 Q2 Q12 Q1 Q29 R32 R35 C28 C91 C10 R14 C51 R62 R103 R101 R117 R105 R203 R108 R100 R96 R57 C26 R34 C40 R95 C11 R33 C27 R7 R6 C29 C6 IC2 W6 R4 R59 R66 R65 R70 R71 R67 C92 C94 R94 C56 C54 R69 SHIFT CK DATA STB SQL SENS AF PSC BATT MOD T 3 VOL R 3 GND 1 13 2 J4 14 to RF unit J2 BOTTOM VIEW ...

Page 21: ...3 D8 C86 C48 C61 C69 R10 W5 L15 R45 C16 C26 C23 R27 R64 R302 R215 R205 D103 C206 R209 R202 C202 W202 L205 C207 C208 L201 W201 C201 C203 C204 L202 R213 R305 L208 R313 R306 C67 R12 C70 R65 R93 R62 C87 R19 R86 C36 C90 R69 R67 R4 C46 C72 C65 C9 C11 C31 D7 R303 R310 R304 C212 L211 AF SENS SQL STB DATA CK SHIFT GND R 3 VOL T 3 MOD BATT PSC 13 1 14 J2 2 to MAIN unit J4 ...

Page 22: ...50 R206 Q12 C84 Q7 C56 Q6 C51 D4 D5 L13 L12 C32 R70 J1 FI3 FI2 B5421B R72 C6 L3 R7 R75 R76 Q16 R74 C93 C92 C91 D102 D101 C210 C209 R207 C205 R301 L206 R83 C5 C95 R73 R16 R25 C7 L4 R30 R29 C20 L11 C53 C54 C50 C52 R31 R34 R59 C217 R311 L210 R208 C218 C102 C216 Q203 R312 L209 C219 C101 EP2 R56 R54 R6 C76 R57 R1 R61 C83 C1 C2 C47 Q1 X2 R3 R2 X1 C79 C63 ...

Page 23: ...144EU LPF IDC 3V IC2A NJM2100M Q6 2SK1829 MIC MUTE IC2B NJM2100M Q23 2SJ144 R58 AF VOL VOL MUTE MC1 KUC3523 PTT SENSE MIC SW MIC R 3 CURRENT AMP R 3 T 3 3V CURRENT AMP Q25 UMZ2N D4 1SS355 3V to LOGIC 3 REG IC6 S 81230SG Q18 2SA1586 Q27 2SC4081 Q28 2SB798 Q101 UMZ1N D5 1SS355 T 3 CURRENT AMP D2 1SS355 PROTECTOR Q29 DTC114EU Q2 UN9214 Q3 DTA123JUA AF MUTE BATT BATTERY J3 COMON LINE TX LINE RX LINE D...

Page 24: ... COM0 COM1 COM2 COM0 COM1 COM2 DS2 LD BU10503J R65 18 k R66 18 k R64 18 k 3 V SHIFT VOL CK DATA STB AF SENS SQL MOD PSC R 3 T 3 BATT 1 2 3 4 5 6 7 8 9 10 11 12 13 14 J4 8 IC2a NJM2100M R30 15 k C73 0 0033 T ID 1 3 2 4 C1 0 0027 C99 0 0033 R2 82 k R203 8 2 k R39 82 k C29 150 P R40 100 k Q2 UN9214 Q3 DTA123JUA Q1 DTA144EU C6 1 PTT2 Q6 2SK1829 RMUTE AFON BEEP Q18 2SA1586 GR R81 10 k R74 10 k C61 0 1 ...

Page 25: ...4 6 P T 3 C23 7 P R202 22 k D2 MA77 C70 470 P D1 MA77 R12 1 k R208 1 k R37 22 k C102 2 P C88 10 C16 470 P R305 3 9 k C62 0 033 R45 8 2 k C68 0 68 R306 8 2 k R10 8 2 k C17 0 033 C61 5 P R88 4 7 k R313 10 R302 10 k VCC1 1 IN1 2 ENB 3 CLK 4 DATA 5 T1 6 LOK 7 CP1 8 FI1 9 FO1 10 FO2 11 FI2 12 CP2 13 GND2 14 XO 15 XI 16 XB 17 VCC2 18 IN2 19 GND1 20 IC1 µPD3140GS R27 100 k R55 15 k R56 15 k R59 15 K C76 ...

Page 26: ...com france com Crta de Gracia a Manresa Km 14 750 08190 Sant Cugat del Valles Barcelona SPAIN Phone 93 590 26 70 Fax 93 589 04 46 URL http www icomspain com Corporate Headquarters 2380 116th Avenue N E Bellevue WA 98004 U S A Phone 425 454 8155 Fax 425 454 1509 URL http www icomamerica com Customer Service Phone 425 454 7619 A C N 006 092 575 290 294 Albert Street Brunswick Victoria 3056 Australia...

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