Icom IC-91A Service Manual
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Icom IC-91A Service Manual

Vhf/uhf digital transceiver
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SERVICE
MANUAL
VHF/UHF FM TRANSCEIVER
VHF/UHF DIGITAL TRANSCEIVER
S-14230HZ-C1
May. 2006

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Summary of Contents for Icom IC-91A

  • Page 1 SERVICE MANUAL VHF/UHF FM TRANSCEIVER VHF/UHF DIGITAL TRANSCEIVER S-14230HZ-C1 May. 2006...
  • Page 2 8. READ the instructions of test equipment thoroughly before connecting equipment to the transceiver. Icom, Icom Inc. and logo 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 UT-121 UNINSTALLATION SECTION CIRCUIT DESCRIPITON RECEIVER CIRCUITS............5-1 TRANSMITTER CIRCUITS .

  • Page 4: Specifications

    25/30/50/100/125 and 200 kHz : 50 Ω (SMA type) • Antenna impedance • Power supply : 10.0–16.0 V DC for external DC power, or specifi ed Icom’s battery pack † • Digital transmission speed : 4.8 kbps † • Voice coding speed : 2.4 kbps...
  • Page 5 SECTION 2 INSIDE VIEWS • LOGIC UNIT • UT-121 (Optional Product ; CODEC UNIT for IC-91AD) Reference (TOP VIEW) frequency oscillator (X1: CR-774) GMSK modem IC (IC202: CMX589AD5) RS-232C interface (IC52: MAX3221IPWR) AMBE audio codec IC (IC101: AMBE-2020) Linear codec IC (IC1: HD64F2238RTF13V) (IC350: AD73311ARSZ) Reset IC...

  • Page 6: Logic Unit

    SECTION 3 DISASSEMBLY INSTRUCTIONS • Removing the rear panel • Removing the RF unit 1 Unscrew 2 screws A and remove the plate B. 1 Unsolder 2 points A. 2 Remove the CODEC unit (UT-121) if installed. (See the 2 Unsolder 3 points B and remove the shield plate C. 3 Unscrew 4 screws D and remove the RF unit from the page 4-1 “2”...
  • Page 7 SECTION 4 UT-121 UNINSTALLATION RECOMMENDATION: Critical technique is necessary for the UT-121 uninstallation, therefore, we recommend you to uninstall it at your dealer or service center. q Turn the power OFF, and remove the battery pack. w Unscrew 2 screws to remove the unit cover. 2 screws Unit cover e Insert the tweezers into the notches of the UT-121, and remove it as shown below.

  • Page 8: Receiver Circuits

    SECTION 5 CIRCUIT DESCRIPTION - 76–118 MHz or 174–260 MHz - 5-1 RECEIVER CIRCUITS This transceiver has two receiving lines called A_BAND and B_ from the D303 D302 antenna BAND for dualwatch capability. A_BAND corresponds to FM/WFM/ AM mode receiving within 0.495–999 MHz range, and B_BAND 174-260 MHz corresponds to FM/FM-N/AM/DV mode receiving within 118–174 D301...
  • Page 9 • While receiving 350–470 MHz While receiving 260–999 MHz band signals, the 1st LO signals are The 350–470 MHz band signals are passed through the LPF (L1– generated at UHF BAND VCO (VCO UNIT; Q101, D101, D104). L3, C1–C6), HPF (L4, C7–C9) and attenuator (D7), then applied If the receiving frequency is 600 MHz or higher, the VCO output to the RF amplifier (Q600) via the band switch (D600) and HPF signal is doubled at the doubler circuit (RF UNIT;...
  • Page 10 5-1-3 2ND IF AND DEMODULATOR CIRCUITS 5-1-3-2 DEMODULATOR CIRCUITS (MAIN UNIT) • FM/WFM mode The amplified IF signal from the limiter amplifier in the IF IC is The 1st IF signal is converted into the 2nd IF signal and FM-demodulated at the quadrature detector (IC100, pins, 10, 11, demodulated in the IF IC.
  • Page 11 • B_BAND 2ND IF AND DEMODULATOR CIRCUITS (FM/AM) Q202 D202 2nd IF signal to the AM demodulator (Q203, Q204) D203 FI200 45.9 MHz TCXO 2nd LO signal Q450 FI201 Q451 (FM-N) X450 Noise Noise Amplifier Detector Limitter Quadrature Amplifier Detector RSSI B_BAND IF IC (IC200) 1st IF signal from the 1st IF amplifier (Q200)

  • Page 12: Transmitter Circuits

    , the MIC signals are output from pin 7 and applied to switching circuit and transmit filters. the IDC (IC302, pin 5) via the ALC amplifier (IC300, pins 3, 5). † Available for IC-91AD or when the optional UT-121 is installed into IC-91A. 5 - 5...

  • Page 13: Pll Circuits

    5-2-4 APC CIRCUIT (RF UNIT) 5-3 PLL CIRCUITS The APC (Automatic Power Control) circuit stabilizes transmit output 5-3-1 VCO CIRCUITS (VCO UNIT AND MAIN UNIT) power and controls it High or Low. The APC of this transceiver is a This transceiver has 5 VCOs; BC BAND VCO, VHF BAND VCO, current monitoring type that detects the transmit signal current of UHF BAND VCO, B_BAND VBVCO and B_BAND UBVCO.
  • Page 14 5-3-2 PLL CIRCUITS (RF AND MAIN UNITS) The phase difference is output from pin 2 as a pulse type signal after being passed through the internal charge pump. The output The PLL circuit provides stable oscillation of the transmit frequency signal is applied to the BC/VHF/UHF BAND VCOs (VCO UNIT) and receive 1st LO frequency.
  • Page 15 • B_BAND PLL CIRCUIT applied to the B_BAND VBVCO/UBVCO (MAIN UNIT) after being The buffer amplified signals from the buffer amplifier (MAIN UNIT; converted into the DC voltage (lock voltage) at the loop filter (MAIN Q353) are applied to the PLL IC (MAIN UNIT; IC400, pin 8). The UNIT;...

  • Page 16: Power Supply Circuits

    “Low”=While the transceiver’s power is OFF. Outputs TX mute signal to the mode switch MUTE (IC301). “High”=While the transmitting is muted. CTCOUT Outputs CTCSS/DTCS signals. † Available for the IC-91AD or when UT-121 is installed into IC-91A. 5 - 9...
  • Page 17 Outputs data signal to the PLL IC’s (MAIN UNIT; PLLDATA IC400, RF UNIT; IC800). Outputs strobe signal to the PLL IC (MAIN BPLSTB UNIT; IC400). † Available for the IC-91AD or when UT-121 is installed into IC-91A. 5 - 10...

  • Page 18: Adjustment Procedures

    SECTION 6 ADJUSTMENT PROCEDURES 6-1 PREPARATION When adjusting IC-91A/AD, these test equipments, OPC-254L and the JIG cables (see the illust below) are required. ¤ REQUIRED TEST EQUIPMENTS EQUIPMENT GRADE AND RANGE EQUIPMENT GRADE AND RANGE Output voltage : 5.0–13.5 V DC...
  • Page 19 ¤ KEY ASSIGNMENTS FOR ADJUSTMENT MODE CAUTION!: BACK UP the originally programmed memory data in the transceiver before starting the adjustment. [DIAL] There is possiblity of losing original memory data when the adjustment is finished. ¤ ENTERING ADJUSTMENT MODE q Turn the power OFF. w Connect the JIG cables (see page 6-1) to the [SP] and [MIC] jacks.

  • Page 20: Transmitter Adjustment

    6-2 TRANSMITTER ADJUSTMENT • Set the specified value using [DIAL], and push [BAND] to store the set value. Then push [2] to move to the next adjustment item. NOTE: “REFERENCE FREQUENCY” should be adjusted before “FM DEVIATION” and “RXBPF.” Otherwise, these adjustments will not be adjusted properly.
  • Page 21 (DTCS, UHF) • Transmitting *Displayed on the function display. †The output level of the standard signal generator (SSG) is indicated as the SSG’s open circuit. ‡Necessary for the IC-91AD or when UT-121 is installed into the IC-91A. 6 - 4...

  • Page 22: Receiver Adjustment

    6-3 RECEIVER ADJUSTMENT • Set the specified value using [DIAL], and push [BAND] to store the set value. Then push [2] to move to the next adjustment item. ADJUSTMENT ITEM ADJUSTMENT CONDITION VALUE RXBPF (A_BAND) • Connect an SSG to the ANT connector and set as; 6T# Dev.
  • Page 23 6-4 RECEIVER ADJUSTMENT (continued) ADJUSTMENT ITEM ADJUSTMENT CONDITION VALUE WFM S-METER • Connect an SSG to the ANT connector and set as; 5# Dev. : 3.5 kHz [S3A] : 1 kHz 1.0–145 MHz bands • Set the SSG as; Frequency : Specified frequencies* †...
  • Page 24 145.0 (146.0)* 40.1 435.0 (445.0)* 60.1 [DTMF] 145.0 (146.0)* 87.5 435.0 (445.0)* 145.1 *[USA] version. 220.1 †Necessary for the IC-91AD or when UT-121 is installed into 305.1 IC-91A. 435.1 535.1 800.1 FM S-METER 145.1 (B_BAND) [S3B] 435.1 6 - 7...

  • Page 25: Logic Unit

    SECTION 7 PARTS LIST • IC-91AD/A [LOGIC UNIT] [LOGIC UNIT] ORDER DESCRIPTION LOCATION ORDER DESCRIPTION 7030005530 S.RES ERJ2GEJ 100 X (10) 37.8/83.7 LOCATION 7030005160 S.RES ERJ2GEJ 105 X (1 M 37.4/85.5 1140013020 S.IC HD64F2238RTF13V 29.9/78.2 7030008010 S.RES ERJ2GEJ 123 X (12 k 40.9/83.1 1130013010 S.IC SN74AHC1G08DCK3...
  • Page 26 [LOGIC UNIT] [LOGIC UNIT] ORDER ORDER DESCRIPTION DESCRIPTION LOCATION LOCATION R323 7030007340 S.RES ERJ2GEJ 153 X (15 k 35.9/52 4030017620 S.CER ECJ0EC1H100C 51.2/69.8 R324 7030007340 S.RES ERJ2GEJ 153 X (15 k 32.8/50 C100 4030017460 S.CER ECJ0EB1E102K 50/38 R325 7030007340 S.RES ERJ2GEJ 153 X (15 k 21.4/47.7 C101 4030011600 S.CER C1608 JB 1E 104K-T...

  • Page 27: Main Unit

    [MAIN UNIT] [LOGIC UNIT] ORDER ORDER DESCRIPTION DESCRIPTION LOCATION LOCATION IC50 1110005230 S.IC µPC2757TB-E3 24.3/17.8 C346 4550007730 S.TAN TEESVJ 0J 106M8R 18.7/46.7 IC100 1110003201 S.IC TA31136FNG (EL) 47.3/27.4 C347 4030017460 S.CER ECJ0EB1E102K 21.2/39.8 IC150 1110005330 S.IC NJM12904V-TE1 18.3/29.3 C348 4030018860 S.CER ECJ0EB0J105K 17.6/46.2 IC200 1110003201 S.IC...
  • Page 28 [MAIN UNIT] [MAIN UNIT] ORDER ORDER DESCRIPTION DESCRIPTION LOCATION LOCATION L200 6200003540 S.COL MLF1608D R22K-T 41.6/34.8 R220 7030005100 S.RES ERJ2GEJ 154 X (150 k 18.2/19.6 L201 6200003540 S.COL MLF1608D R22K-T 42.2/33 R221 7030005240 S.RES ERJ2GEJ 473 X (47 k 15.3/23 L202 6200003540 S.COL MLF1608D R22K-T 41.4/20.9...
  • Page 29 [MAIN UNIT] [MAIN UNIT] ORDER ORDER DESCRIPTION DESCRIPTION LOCATION LOCATION C155 4550000460 S.TAN TEESVA 1C 105M8R 11.8/32.1 R650 7030005160 S.RES ERJ2GEJ 105 X (1 M 20.3/9.7 C156 4030016930 S.CER ECJ0EB1A104K 15.8/26 R651 7030005050 S.RES ERJ2GEJ 103 X (10 k 21.3/8.5 C157 4030016930 S.CER ECJ0EB1A104K 13.9/29.2...
  • Page 30 [MAIN UNIT] [MAIN UNIT] ORDER ORDER DESCRIPTION DESCRIPTION LOCATION LOCATION C407 4030017420 S.CER ECJ0EC1H470J 31.4/4.1 C708 4030017420 S.CER ECJ0EC1H470J 28.6/45.7 C408 4030017420 S.CER ECJ0EC1H470J 29.7/6.6 C709 4030017420 S.CER ECJ0EC1H470J 21.6/47.7 C409 4030017420 S.CER ECJ0EC1H470J 28.1/4.6 C710 4030017420 S.CER ECJ0EC1H470J 19.9/46.6 C410 4030016930 S.CER ECJ0EB1A104K 31.5/11.6...

  • Page 31: Rf Unit

    [RF UNIT] [RF UNIT] ORDER ORDER DESCRIPTION DESCRIPTION LOCATION LOCATION D309 1790001260 S.DIO MA2S077-(TX) 3.2/31.6 IC100 1110005590 S.IC µPC2762TB-E3 34/14.3 D310 1790001240 S.DIO MA2S728-(TX) 4.1/26.3 IC150 1110004050 S.IC NJM3404AV-TE1 43.8/34.7 D311 1790001621 S.DIO 1SV308 (TPL3) 2.7/24.5 IC800 1130013000 S.IC LMX2313USLDX/NOPB 20.6/21.9 D400 1790001621 S.DIO...
  • Page 32 [RF UNIT] [RF UNIT] ORDER ORDER DESCRIPTION DESCRIPTION LOCATION LOCATION L204 6200002041 S.COL NLV25T-101J 11.6/33.1 R153 7030005110 S.RES ERJ2GEJ 224 X (220 k 44.5/33.9 L250 6200004590 S.COL MLF1608D R18K-T 8.6/30.3 R154 7030005160 S.RES ERJ2GEJ 105 X (1 M 49.1/35.1 L251 6200004600 S.COL MLF1608D R15K-T 8.2/29.1 R155...
  • Page 33 [RF UNIT] [RF UNIT] ORDER ORDER DESCRIPTION DESCRIPTION LOCATION LOCATION R830 7030010090 S.RES ERJ2GEJ 180 X (18) 18.8/24.6 R458 7030005090 S.RES ERJ2GEJ 104 X (100 k 24.1/26.9 R831 7030010090 S.RES ERJ2GEJ 180 X (18) 17.1/24 R459 7030005530 S.RES ERJ2GEJ 100 X (10) 20.2/27.3 R832 7030010090 S.RES ERJ2GEJ 180 X (18)
  • Page 34 [RF UNIT] [RF UNIT] ORDER ORDER DESCRIPTION DESCRIPTION LOCATION LOCATION C114 4030017460 S.CER ECJ0EB1E102K 48.1/24.7 C315 4030017380 S.CER ECJ0EC1H050B 12/36 C116 4030017640 S.CER ECJ0EC1H150J C316 4030016790 S.CER ECJ0EB1C103K 11.5/38.8 [USA], [USA-1] only T 48.5/25.9 C317 4030017460 S.CER ECJ0EB1E102K 6.4/37.6 C117 4030017460 S.CER ECJ0EB1E102K 41/20.3 C318...
  • Page 35 [RF UNIT] [RF UNIT] ORDER ORDER DESCRIPTION DESCRIPTION LOCATION LOCATION C822 4340000260 S.MLR ECPU1C104MA5 11.8/21.5 C517 4030017640 S.CER ECJ0EC1H150J 31.4/17.5 C823 4550007120 S.TAN F92 1D 224MPA 11.9/18.5 C518 4030017460 S.CER ECJ0EB1E102K 30.9/37.9 C826 4030017420 S.CER ECJ0EC1H470J 15.6/17.8 C519 4030017630 S.CER ECJ0EC1H120J 31.7/35.3 C830 4030017440 S.CER ECJ0EC1H221J...
  • Page 36 [VCO UNIT] [VCO UNIT] ORDER ORDER DESCRIPTION DESCRIPTION LOCATION LOCATION 1530003560 S.TR 2SC5195-T1 10.4/16.5 4030017460 S.CER ECJ0EB1E102K 3.1/13.6 1590003280 S.TR UNR9211J-(TX) 4.6/15.1 4030017690 S.CER ECJ0EC1H121J 9.1/17.9 1530003560 S.TR 2SC5195-T1 14/9.6 4030016790 S.CER ECJ0EB1C103K 7.9/17.6 1590003280 S.TR UNR9211J-(TX) 18.1/17.4 4030016790 S.CER ECJ0EB1C103K 5.5/17 Q101 1530003260 S.TR...
  • Page 37 [MAIN UNIT] • UT-121 (Optional product; [CODEC UNIT] for IC-91AD) ORDER DESCRIPTION [MAIN UNIT] LOCATION C110 4030017420 S.CER ECJ0EC1H470J 29.1/7.3 ORDER DESCRIPTION C111 4030017460 S.CER ECJ0EB1E102K 22.9/16.2 LOCATION C112 4030016930 S.CER ECJ0EB1A104K 26.4/19 1180002371 S.REG R1111N321B-TR-F 30.6/13.6 C113 4030016930 S.CER ECJ0EB1A104K 24.1/18.4 IC101 1130010920 S.IC...
  • Page 38 8210022570 2888 front panel assembly [IC-91AD] 8930068290 2888 jack cap (incl. MP7) 8930068300 2888 PTT rubber 8210022960 2888 front panel (A) assembly [IC-91A] 8930068350 2888 PTT plate (incl. MP7) 8930069020 O-ring (BG) 8310066690 2888 window plate (A) [IC-91A] MP10 8930068360...
  • Page 39 MP22 (L) MP9 (L) LOGIC UNIT CODEC UNIT MP9 (L) MP3 (C) MP9 (L) MP4 (L) MP2 (C) MP6 (C) MP9 (L) DS1 (L) MP9 (L) MP4 (C) MP23 (L) MP10 (L) MC300 MP16 (C) MP23 (C) MP15 (C) MP19 (C) MP18 (C) MP24 (C) MP21 (L)
  • Page 40 SECTION 9 SEMICONDUCTOR INFORMATION • TRANSISTORS AND FET'S • DIODES 2SA1362 GR 2SB1132 T100 R 2SB1201 S 2SB1462 R 2SC4081 T106 S 1SS362 1SS364 1SV271 1SV286 1SV307 (Symbol: AEG) (Symbol: BAR) (Symbol: B1201) (Symbol: AR) (Symbol: BS) (Symbol: C3) (Symbol: BF) (Symbol: TG) (Symbol: T7) (Symbol: TX)
  • Page 41 SECTION 10 BOARD LAYOUTS 10-1 LOGIC UNIT 10-2 MAIN UNIT EXT MIC EXT SP • TOP VIEW • TOP VIEW 10-4 UT-121 ( Optional Product ; CODEC UNIT for IC-91AD) • TOP VIEW J702 EXTMIC INTSP CLONE ANOIS DIUD BNOIS DICK BRSSI S-LV...
  • Page 42 • BOTTOM VIEW (MAIN UNIT) VOL/DIAL • BOTTOM VIEW (LOGIC UNIT) • BOTTOM VIEW (UT-121 ( Optional Product ; CODEC UNIT for IC-91AD)) J401 EXTMIC INTSP CLONE ANOIS to LOGIC unit J400 DIUD BNOIS DICK BRSSI S-LV INTPTT ATONE DATA DAFOUT BTONE IOSTB3...
  • Page 43 SECTION 11 BLOCK DIAGRAM Q602: 2SB1132 Q600: 2SB1132 Q603: XP1501 Q601: XP1501 MAINR3 MAINR3, MAINR3A, MAINR3B Q1: 2SC5195 BC: 62.145-131.645MHz Q604: XP1115 RF UNIT Q2: UNR9211 RFR3 Q800: XP1115 D1: 1SV325 Q801: UNR9115 D2: 1SV308 Q200: 2SC5006 IC701: CD4094 D3: 1SV325 D4: 1SS400 Q1: UNR9211 Q803: 2SB1132...
  • Page 44 SECTION 12 VOLTAGE DIAGRAMS 12-1 LOGIC UNIT LOGIC UNIT IC52 MAX3221IPWR DATA 0.22 FORCEOFF READY EP50 IC560 0.22 EP53 T1OUT XC6202P502PR 5.07V J200 FORCEON 0.22 C200 T1IN INVALID EP51 MUTE ON: 0V IC550 C201 7.39V OFF: 6.07V R1OUT R1IN NJM2070M C202 Q105 R553...
  • Page 45 12-2 MAIN UNIT MAIN UNIT A FM RX: 2.42V A TONE ON: 3.25V TX: 0.46V OFF: 0.50V A WFM RX: 0V MAINR3A B FM RX: 2.41V J703 Q150 R129 C132 Q105 Q101 D100 C131 C127 UNR9115J 0.001 UNR9115J R121 0.47 R120 UNR9215J C106...
  • Page 46 12-3 RF UNIT RF UNIT R162 AR3C NTCG16 TTEMP RX: 0V Q800 TX: 2.96V C176 XP1115 0.001 R167 VAVCOC 220K R165 EP104 C172 C173 R163 C177 R166 NTCG10 D101 220P 220P 0.001 C174 C175 MA132WK J800 470P 470P C803 C840 3.37V Q105 0.001...

  • Page 47: Vco Unit

    12-4 VCO UNIT VCO UNIT A: 3.38V B: 2.41V C: 2.39V L203 LOOUT UVCO3 Q202 L202 C208 C207 2SC5006 PLLOUT 8.2N 0.001 0.001 C213 L201 to RF C211 C210 C209 unit J800 BCVCO3 R208 VSHIFT VVCO3 C206 R207 0.001 BCLV 1SS400 C200 0.001...

  • Page 48: Ut-121 (Optional Product; Codec Unit For Ic-91Ad)

    12-5 UT-121 (Optional Product ; CODEC UNIT for IC-91AD) CODEC UNIT AMBECLK AMBERES Explanatory notes DCEL AMBESTB VOLTAGE LINE RXDT AMBEEPR TX LINE RXCK RX LINE R1111N321B TXDT COMMON LINE VOUT TXCK to LOGIC DMOD unit J400 AMODIN DAFOUT RX DV: 5.06V AMBETXD RX FM: 5.08V BTONE...
  • Page 49 Phone : +34 (93) 590 26 70 Fax : +34 (93) 589 04 46 Glenwood Centre #150-6165 : http://www.icomspain.com Highway 17 Delta, B.C., V4K 5B8, Canada E-mail : icom@icomspain.com Phone : +1 (604) 952-4266 Fax : +1 (604) 952-0090 : http://www.icomcanada.com E-mail : info@icomcanada.com Unit 9, Sea St., Herne Bay, Kent, CT6 8LD, U.K.
  • Page 50 S-14230HZ-C1 1-1-32, Kamiminami, Hirano-ku, Osaka 547-0003, Japan © 2006 Icom Inc.

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