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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.
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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 •...
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‘ ‘ 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...
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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)
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...
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.
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.
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;...
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...
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: 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 •...
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.
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[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...
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...
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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)
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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...
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...
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...
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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...
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