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Icom IC-4088SR Service Manual

Pmr446 fm transceiver
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SERVICE
MANUAL
PMR446 FM TRANSCEIVER

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Summary of Contents for Icom IC-4088SR

  • Page 1 SERVICE MANUAL PMR446 FM TRANSCEIVER...
  • Page 2 8. READ the instructions of test equipment thoroughly before connecting equipment to the transceiver. Icom, Icom Inc. and are registered trademarks of Icom Incorporated (Japan) in the United States, the United Kingdom, Germany, France, Spain, Russia and/or other countries.

  • Page 3: Table Of Contents

    TABLE OF CONTENTS SECTION SPECIFICATIONS SECTION INSIDE VIEWS SECTION DISASSEMBLY INSTRUCTIONS SECTION CIRCUIT DESCRIPITON RECEIVER CIRCUITS ........... . . 4-1 TRANSMITER CIRCUITS .
  • Page 4 SECTION 1 SPECIFICATIONS ‘ ‘ GENERAL • Number of channel : 8 channels (simplex; 446.00625–446.09375 MHz) • Type of emission : 8K50F3E (FM) • Frequency stability : ±2500 Hz (±5.6 ppm) • Frequency resolution : 12.5 kHz : 50 Ω •...
  • Page 5 ‘ ‘ CHANNEL FREQUENCY LIST Frequency (MHz) Channel No. Frequency (MHz) Channel No. 446.00625 446.05625 446.01875 446.06875 446.03125 446.08125 446.04375 446.09375 ‘ ‘ CTCSS FREQUENCY LIST Channel No. Frequency (Hz) Channel No. Frequency (Hz) Channel No. Frequency (Hz) 67.0 107.2 167.9 71.9 110.9...
  • Page 6 SECTION 2 INSIDE VIEWS • MAIN UNIT TOP VIEW BOTTOM VIEW T+3 Regulator Audio amplifier (Q308: 2SB798) (IC305: NJM2070) R+3 Regulator (Q304: 2SA1586) EEPROM (IC300: BR24C02) (IC301: PD78F9407AGK) +3 Regulator (IC303: R1121N301B) • RF UNIT TOP VIEW BOTTOM VIEW 2nd IF filter FM IF IC (Fl3: CFWM450G) (IC1: TA31136FN)

  • Page 7: Section 3 Disassembly Instructions

    SECTION 3 DISASSEMBLY INSTRUCTIONS • • REMOVING THE RF UNIT REMOVING THE REAR PANEL 1 Unscrew 1 screw A, and 5 screws B. 1 Unscrew 2 screws H. 2 Remove the rear panel in the direction of the arrow. 2 Unsolder 2 points I, and remove the RF unit. RF unit Rear panel Main unit...

  • Page 8: Receiver Circuits

    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 to a 2nd IF Received signals from the antenna are passed through the signal.

  • Page 9: Transmiter Circuits

    4-1-6 SQUELCH CIRCUIT (RF AND MAIN UNITS) 4-2-3 DRIVE/POWER AMPLIFIER CIRCUITS (1) NOISE SQUELCH (RF UNIT) The noise squelch circuit cuts out AF signals when no RF The drive/power amplifier circuit amplifies the VCO oscillat- signals are received. By detecting noise components in the ing signal to the output power level.

  • Page 10: Power Supply Circuits

    4-4 POWER SUPPLY CIRCUITS Port Description VOLTAGE LINE number name LINE DESCRIPTION Input port for the PLL unlock signal from the PLL IC (RF unit; IC2). UNLK The voltage from the connected battery or Low : During unlock. power supply from DC IN (J302). Input port for the PTT switch from the Common 3 V converted from the VCC line at the external mic jack (MAIN unit;...

  • Page 11: Section 5 Adjustment Procedures

    SECTION 5 ADJUSTMENT PROCEDURES 5-1 PREPARATION • When adjusting the IC-4088SR, *HM-75A (modified HM-75A see illustration at JIG MICROPHONE OPTIONAL SPEAKER-MICROPHONE; page5-2) is required. • All adjustment items must be preformed at “ADJUSTMENT MODE”. (See below in detail) ‘ ‘ REQUIRED TEST EQUIPMENT...
  • Page 12 : HM-75A’s [A] key • Change the adjustment channel : IC-4088SR’s [UP]/[DN] keys • Change the adjustment group : IC-4088SR’s [MODE]+ [UP]/[DN] keys ADJUSTMENT ITEMS ‘ ‘ When entering adjustment mode, displayed adjustment items indicator on LCD as follow. • Reference frequency adjustment : Displayed •...

  • Page 13: Adjustment Mode Adjustments

    5-2 ADJUSTMENT MODE ADJUSTMENTS The following adjustment must be performed at “ADJUSTMENT MODE”. ADJUSTMENT ADJUSTMENT CONDITION MEASUREMENT VALUE HM-75A’s KEY REFERENCE • Operating channel : Ch 8 Loosely couple a fre- [∫]/[√] 446.09375 MHz FREQUENCY • Transmitting quency counter to the [Fr] antenna.

  • Page 14: Section 6 Parts List

    SECTION 6 PARTS LIST [MAIN UNIT] [MAIN UNIT] ORDER ORDER DESCRIPTION DESCRIPTION IC300 1130011230 S.IC BR24C02FV-WE2 R369 7030007570 S.RESISTOR ERJ2GEJ 122X (1.2 kΩ) IC301 1140011430 S.IC µPD789407AGK-A81-9EU (FX2624A3) R373 7030005080 S.RESISTOR ERJ2GEJ 823 X (82 kΩ) IC302 1110005820 S.IC R3112N281A-TR R374 7030009140 S.RESISTOR...
  • Page 15 [MAIN UNIT] [MAIN UNIT] ORDER ORDER DESCRIPTION DESCRIPTION C332 4030017460 S.CERAMIC ECJ0EB1E102K W305 7030010040 S.RESISTOR ERJ2GE-JPW C333 4030017730 S.CERAMIC ECJ0EB1E471K W307 7030010040 S.RESISTOR ERJ2GE-JPW C334 4030016930 S.CERAMIC ECJ0EB1A104K C335 4030017440 S.CERAMIC ECJ0EC1H221J C336 4030017450 S.CERAMIC ECJ0EB1E271K 0910056431 B 6003A C337 4030011810 S.CERAMIC C1608 JB 1A 224K-T...
  • Page 16 [RF UNIT] [RF UNIT] ORDER ORDER DESCRIPTION DESCRIPTION 6200003640 S.COIL MLF1608E 100K-T 4030017730 S.CERAMIC ECJ0EB1E471K 6200003640 S.COIL MLF1608E 100K-T 4030017630 S.CERAMIC ECJ0EC1H120J 6200005720 S.COIL ELJRE 33NG-F 4030017600 S.CERAMIC ECJ0EC1H080C 6200006980 S.COIL ELJRE R10G-F 4030017460 S.CERAMIC ECJ0EB1E102K 6200005710 S.COIL ELJRE 27NG-F 4030016950 S.CERAMIC ECJ0EB1A473K...
  • Page 17 [RF UNIT] ORDER DESCRIPTION 7030010040 S.RESISTOR ERJ2GE-JPW 7030010040 S.RESISTOR ERJ2GE-JPW 7030003860 S.RESISTOR ERJ3GE JPW V 7030010040 S.RESISTOR ERJ2GE-JPW 0910056422 B 5925B 6910013310 S.BEAD MMZ1608D121B M.=Mounted side (T: Mounted on the Top side, B: Mounted on the Bottom side) S.=Surface mount 6 - 4...

  • Page 18: Cabinet Parts

    SECTION 7 MECHANICAL PARTS AND DISASSEMBLY 7-2 ACCESSORIES 7-1 CABINET PARTS [CHASSIS PARTS] REF. NO. ORDER NO. QTY. REF. NO. ORDER NO. QTY. DESCRIPTION DESCRIPTION 8930045332 2045 Belt clip-2 2510001120 Speaker SDRS-3650P-008 3310003060 Antenna 2628 ANT [EUR] 3310003120 Antenna 2628 SHORT ANT M [EUR-1] 8210019370 2628 Front panel 8110007900 2628 Rear cover...
  • Page 19 MP301 (M) Antenna marking here. Back side DS300 (M) EP1 (C) MP302 (M) L: for IC-4088E MP1 (RF) M: for IC-4088SR H: for IC-4088S or IC-4088A EP303 (M) MP20 (C) R406 (M) MP36 (C) J301 (M) MP32 (C) MP303 (M)
  • Page 20 SECTION 8 SEMI-CONDUCTOR INFORMATION • TRANSISTOR AND FET’S 2SA1362 GR 2SA1586 GR 2SB798 DK 2SB1132Q 2SC3356 (Symbol: AEG) (Symbol: SG) (Symbol: DK) (Symbol: BA) (Symbol: R22) 2SC4116GR 2SC4117GR 2SC4213 B 2SC4215 O 2SC4226 R25 (Symbol: LG) (Symbol: DG) (Symbol: AB) (Symbol: QO) (Symbol: R25) 2SC4228 R44...

  • Page 21: Section 9 Board Layouts

    SECTION 9 BOARD LAYOUTS 9-1 MAIN UNIT • TOP VIEW J300 to the RF unit J2 J303 J301 R396 C364 C354 C347 J300 C343 Q307 C361 R376 C324 J300 R374 R365 R392 R384 R366 R394 R433 R357 C339 R378 C348 C335 C346 C317...
  • Page 22 • BOTTOM VIEW EP306 R401 R405 R404 C378 C382 Q316 C349 R403 C381 W301 EP304 C368 C374 R349 C319 Q308 C341 R410 R343 R377 R422 C392 C402 R379 C393 R369 D303 C350 R414 W307 C325 C383 C326 R334 R327 C313 C394 EP302 IC301...

  • Page 23: Rf Unit

    9-2 RF UNIT • TOP VIEW B5925B C120 C102 C118 9 - 3...
  • Page 24 • BOTTOM VIEW to the MAIN unit J300 C111 C110 C112 C117 9 - 4...

  • Page 25: Block Diagram

    SECTION 10 BLOCK DIAGRAM ANTENNA FI3: CFWM450G FI2: FL-297 FI4: NSVS647 CDBC450CX24 1st MIX 1st IF: 21.7MHz TX/RX CERAMIC XTAL Q2: 3SK320 Q3: 2SC4215 Q1: 2SC4228 D1, D2, D3, D4: 1SV308 × 4 TX/RX: 446.00625 – 446.09375MHz 2nd Lo: D6, D7: MA2S077 21.25MHz VCO3 VCO3...

  • Page 26: Voltage Diagram

    SECTION 11 VOLTAGE DIAGRAM NOTES : Voltage line C: COMMON C: COMMON EXT DC: Using external power supply BP: Using the battery Common line T: TX TX line R: RX CHG: While charging the battery 11-1 MAIN UNIT RX line R399 R403 *: EXT-PTT...

  • Page 27: Rf Unit

    11-2 RF UNIT NOTES : ANTENNA Voltage line C: COMMON C: COMMON Common line T: TX TX line R: RX RX line CFWM450G R: 1.87 470 P T: 0.00 R: 0.18 T: 0.00 C112 FL-297 NSVS647 82 k 2SC4228R45 12 nH 18 nH 17 nH 17 nH...
  • Page 28 Unit 9, Sea St., Herne Bay, Kent, CT6 8LD, U.K. Phone : +44 (01227) 741741 Fax : +44 (01227) 741742 : http://www.icomuk.co.uk Icom (Australia) Pty. Ltd. E-mail : info@icomuk.co.uk A.B.N. 88 006 092 575 290-294 Albert Street, Brunswick, Victoria, 3056, Australia Icom France S.a...
  • Page 29 S-13914IZ-C1-q 1-1-32, Kamiminami, Hirano-ku, Osaka, 547-0003, Japan © 2003–2004 Icom Inc.

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