Icom PMR446 Service Manual
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Icom PMR446 Service Manual

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SERVICE
MANUAL
PMR446 FM TRANSCEIVER

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Summary of Contents for Icom PMR446

  • Page 1 SERVICE MANUAL PMR446 FM TRANSCEIVER...
  • Page 2 INTRODUCTION This service manual describes the latest service information for the IC-446S PMR446 FM TRANSCEIVER at the time of publication. VERSION SYMBOL BODY COLOR BLACK Europe EUR-1 YELLOW BLACK General GEN-1 YELLOW To upgrade quality, all electrical or mechanical parts and internal circuits are subject to change without notice or oblig- ation.

  • Page 3: Table Of Contents

    TABLE OF CONTENTS SECTION SPECIFICATIONS SECTION INSIDE VIEWS SECTION DISASEMBLY INSTRUCTION SECTION CIRCUIT DESCRIPTION RECEIVER CIRCUITS ........... . .4-1 TRANSMITER CIRCUITS .
  • Page 4 SECTION 1 SPECIFICATIONS ‘ ‘ GENERAL ‘ ‘ CHANNEL FREQUENCY LIST Channel Frequency Channel Frequency Number of channels : 8 ch (MHz) (MHz) Type of emission : 8K50F3E 446.00625 446.05625 Frequency stability : ±2.5 kHz 446.01875 446.06875 446.03125 446.08125 Frequency resolution : 12.5 kHz 446.04375 446.09375...
  • Page 5 SECTION 2 INSIDE VIEWS • MAIN UNIT TOP VIEW BOTTOM VIEW AF amplifier (IC9: NJM2070M) T+3 Current amplifier EEPROM Q27: 2SC4081 (IC3: AT24C02N) Q28: 2SB798 Q101: UMZ1N D5: 1SS355 (IC1: µPD753036GK) R+3 Current amplifier (Q18: 2SA1586) +3 Regurator (IC6: S-81230SG) •...

  • Page 6: Disasembly Instruction

    SECTION 3 DISASEMBLY INSTRUCTION • • REMOVING THE MAIN UNIT REMOVING THE REAR PANEL 1 Unscrew 2 screws, E. 1 Unscrew 1 screw A , and 4 screws B. 2 Remove the PTT rubber, F. 2 Remove the rear panel in the direction of the arrow. 3 Unsolder 2 points, G, and remove the MAIN unit.

  • Page 7: Circuit Description

    SECTION 4 CIRCUIT DESCRIPTION 4-1 RECEIVER CIRCUITS 4-1-4 2ND MIXER AND DEMODULATOR CIRCUITS (RF UNIT) 4-1-1 ANTENNA SWITCHING CIRCUIT (RF UNIT) The 2nd mixer circuit converts the 1st IF signal into a 2nd IF Received signals from the antenna connector are passed signal.

  • Page 8: Transmitter Circuits

    4-1-6 SQUELCH CIRCUIT (RF AND MAIN UNITS) 4-2-2 MODULATION CIRCUIT (RF UNIT) • NOISE SQUELCH The modulation circuit modulates the VCO oscillating signal The noise squelch circuit cuts out AF signals when no RF (RF signal) using the microphone AF signals. signals are received.

  • Page 9: Power Supply Circuits

    4-4 POWER SUPPLY CIRCUITS Port Description number name VOLTAGE LINE Outputs data signals to the PLL IC (RF LINE DESCRIPTION PLLDA unit; IC1). BATT The voltage from the connected battery cells. Outputs strobe signals for the PLL IC Common 3 V converted from the BATT line at PLLST (RF unit;...

  • Page 10: Adjustment Procedures

    SECTION 5 ADJUSTMENT PROCEDURES 5-1 PREPARATION REQUIRED TEST EQUIPMENT EQUIPMENT GRADE AND RANGE EQUIPMENT GRADE AND RANGE Output voltage : 4.5 V DC Frequency range : 300–3000 Hz DC power supply Audio generator Current capacity : 1 A or more Measuring range : 1–500 mV Frequency range...

  • Page 11: Pll And Transmitter Adjustments

    5-2 PLL AND TRANSMITTER ADJUSTMENTS ADJUSTMENT MEASUREMENT POINT ADJUSTMENT ADJUSTMENT CONDITION VALUE UNIT LOCATION UNIT ADJUST REFERENCE • Operating channel : Ch 01 Loosely couple a fre- 466.00625 MHz FREQUENCY • Transmitting panel quency counter to the antenna. OUTPUT • Operating channel : Ch 01 Connect an RF power 470 mW R206...

  • Page 12: Receiver Adjustment

    5-3 RECEIVER ADJUSTMENT MEASUREMENT ADJUSTMENT ADJUSTMENT CONDITION VALUE ADJUSTMENT UNIT LOCATION SQUELCH • Operating channel : Ch 04 Front Push and hold • Connect an SSG to J1 on the RF unit panel [MODE] and set as: [DOWN] keys for Frequency : 446.04375 MHz 1 sec.
  • Page 13 SECTION 6 PARTS LIST [MAIN UNIT] [MAIN UNIT] ORDER ORDER DESCRIPTION DESCRIPTION 1140008770 S.IC µPD753036GK-559-BE9 7210001970 VARIABLE RV-244 1110002820 S.IC NJM2100M-T1 7030003680 S.RESISTOR ERJ3GEYJ 104 V (100 kΩ) ERJ3GEYJ 470 V (47 Ω) 1140008350 S.IC AT24C02N-10SI-2.7 7030003280 S.RESISTOR 1110004710 S.IC S-80928ANMP-DDR-T2 7030003680 S.RESISTOR ERJ3GEYJ 104 V (100 kΩ)
  • Page 14 [MAIN UNIT] [RF UNIT] ORDER ORDER DESCRIPTION DESCRIPTION 4030006880 S.CERAMIC C1608 JB 1H 472K-T-A 1130007610 S.IC µPD3140GS-E1 (DS8) 4030011600 S.CERAMIC C1608 JB 1C 104KT-N 1110003200 S.IC TA31136FN (EL) 4030006860 S.CERAMIC C1608 JB 1H 102K-T-A 4030011600 S.CERAMIC C1608 JB 1C 104KT-N 4030006900 S.CERAMIC C1608 JB 1E 103K-T-A 1530002600 S.TRANSISTOR...
  • Page 15 [RF UNIT] [RF UNIT] ORDER ORDER DESCRIPTION DESCRIPTION 7030003550 S.RESISTOR ERJ3GEYJ 822 V (8.2 kΩ) 4030007020 S.CERAMIC C1608 CH 1H 120J-T-A ERJ3GEYJ 681 V (680 Ω) 7030003420 S.RESISTOR 4030007050 S.CERAMIC C1608 CH 1H 220J-T-A 7030003640 S.RESISTOR ERJ3GEYJ 473 V (47 kΩ) 4030007050 S.CERAMIC C1608 CH 1H 220J-T-A ERJ3GEYJ 221 V (220 Ω)

  • Page 16: Mechanical Parts And Disassembly

    SECTION 7 MECHANICAL PARTS AND DISASSEMBLY [CHASSIS PARTS] [UNPACKING] REF. NO. ORDER NO. QTY. REF. NO. ORDER NO. QTY. DESCRIPTION DESCRIPTION 8930045331 2045 belt clip-1 2510000960 Speaker K036NA500-26 8820001040 2045 screw 3310002110 Antenna 2123 ANT 8210015181 2045 front panel-1 [BLACK] 8210016101 2045 front panel (A)-1 [YELLOW] 8210015191 2045 rear panel-1...
  • Page 17 EP1 (C) MP11 (C) MP22 (C) MP24 (C) MP8 (C) MP23 (C) MP30 (C) MP9 (C) MP14 (C) MP2 (RF) MP5 (RF) MP25 (C) MP20 (C) MP1 (RF) MP19 (C) MP3 (C) MP13 (C) MP7 (C) MP16 (C) RF unit MP24 (C) DS2 (M) MP17 (C)

  • Page 18: Semi-Conductor Information

    SECTION 8 SEMI-CONDUCTOR INFORMATION • TRANSISTOR AND FET’S • DIODES 1SS355 TE-17 1SV284 MA2S077 MA2S728 MA77 2SA1362-GR 2SA1586-GR 2SB798-T2 DK 2SC3356 R24-T2B 2SC4081 T107S (Symbol: AEG) (Symbol: SG) (Symbol: DK) (Symbol: R24) (Symbol: BS) (Symbol: A) (Symbol: TL ) (Symbol: S) (Symbol: B) (Symbol: 4B) 2SC4213-B...

  • Page 19: Board Layouts

    SECTION 9 BOARD LAYOUTS 9-1 MAIN UNIT • TOP VIEW R201 Q101 R200 D101 9 - 1...
  • Page 20 • BOTTOM VIEW to RF unit J2 R106 R112 R100 R101 R103 TEST B5420B 9 - 2...

  • Page 21: Rf Unit

    9-2 RF UNIT • TOP VIEW to MAIN unit J4 R302 R303 R310 L211 Q14 Q13 R215 R305 R205 D103 R213 R202 R209 C206 C202 C207 L204 9 - 3...
  • Page 22 • BOTTOM VIEW B5421B C217 R311 R208 L210 C218 Q203 C216 C102 R206 L206 9 - 4...
  • Page 23 SECTION 10 BLOCK DIAGRAM CHASSIS UNT RF UNIT D7: MA2S077 TA31136FN D101: MA2S077 CDBCA450CX24 Q3: 2SC5194 Q1: 2SC4215 D102: MA2S077 FI3:CFWM450G FI2: FL-297 FI1: NSVS647 2nd MIX 3SK284 1st IF: 21.7 MHz CERAMIC XTAL Q13: 2SC4081 1st MIX Q14: 2SA1586 TX/RX: Frequency D8 : 1SS355 2nd.Lo: 21.25 MHz...

  • Page 24: Main Unit

    SECTION 11 VOLTAGE DIAGRAM 11-1 MAIN UNIT : COMMON : TX R117 R100 R101 R102 : RX 100 k 100 k 100 k 100 k 100 k 100 k 100 k SO : SQL OPEN SHIFT SC : SQL CLOSE BATT LON : LIGHT ON DATA...

  • Page 25: Rf Unit

    11-2 RF UNIT CHASSIS T: 0 T: 0 T: 0 T: 0 T: 0 T: 0 T: 0.85 R: 1.83 R: 0.72 R: 2.19 R: 0.27 R: 2.28 R: 0.77 R: 0 C219 L206 R310 FL-297 0.001 82 k 12 nH 18 nH 330 k 2SC4226 R25...
  • Page 26 290-294 Albert Street, Brunswick, Victoria, 3056, Australia : http://www.icomuk.co.uk Phone : 03 9387 0666 Fax : 03 9387 0022 : http://www.icom.net.au Zac de la Plaine, Rue Brindejonc des Moulinais BP 5804, 31505 Toulouse Cedex, France 6F No. 68, Sec. 1 Cheng-Teh Road, Taipei, Taiwan, R.O.C.
  • Page 27 S-136007II-CD 6-9-16, Kamihigashi, Hirano-ku, Osaka, 547-0002, Japan © 1999 Icom Inc.

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