IC718.pdf

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1、S-13701MZ-C1 2000 Icom Inc.6-9-16, Kamihigashi, Hirano-ku, Osaka 547-0002, Japan Count on us! HF TRANCEIVER iC-718 iC-718 KB2LJJ Radio Mods Database and Manuals REPAIR NOTES 1. Make sure a problem is internal before disassembling the transceiver. 2. DO NOT open the transceiver until the transceiver

2、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 insulated tuning tool MUST be used for all adjustments. 5. DO NOT keep power ON for a long time when the transceiver is defective

3、. 6. DO NOT transmit power into a signal generator or a sweep generator. 7. ALWAYS connect a 50 dB or 60 dB attenuator between the transceiver and a deviation meter or spectrum analyser when using such test equipment. 8. READ the instructions of test equipment thoroughly before connecting equipment

4、to the transceiver. To upgrade quality, all electrical or mechanical parts and internal circuits are subject to change without notice or obligation. DANGER NEVER connect the transceiver to an AC outlet or to a DC power supply that uses more than 16 V. This will ruin the transceiver. DO NOT expose th

5、e transceiver to rain, snow or any liq- uids. DO NOT reverse the polarrities of the power supply when connecting the tranceiver. DO NOT apply an RF signal of more than 20 dBm (100 mW) to the antenna connector. This could damage the transceivers front end. ORDERING PARTS Be sure to include the follow

6、ing four points when ordering replacement parts: 1. 10-digit order numbers 2. Component part number and name 3. Equipment model name and unit name 4. Quantity required 1110001810 S.ICTA7368FIC-718 MAIN UNIT 1 piece 8810009650 Screw FH BT M3 8 NI-ZU IC-718 CHASSIS6 pieces Addresses are provided on th

7、e inside back cover for your convenience. INTRODUCTION This service manual describes the latest service information for the IC-718 HF TRANCEIVER at the time of publication. MODEL IC-718 VERSION U.S.A. Europe Italy France Spain Other Korea U.S.A. SYMBOL USA EUR ITA FRA ESP OTH KOR USA-1 6-9-16, Kamih

8、igashi, Hirano-ku, Osaka 547-0002, Japan Phone : 06 6793 5302 Fax: 06 6793 0013 URL: http:/www.icom.co.jp/world/index.html Communication Equipment Himmelgeister Str. 100, D-40225 Dsseldorf, Germany Phone: 0211 346047Fax : 0211 333639 URL: Unit 9, Sea St., Herne Bay, Kent, CT6 8LD, U.K. Phone: 01227

9、741741 Fax : 01227 741742 URL: http:/www.icomuk.co.uk Zac de la Plaine, Rue Brindejonc des Moulinais BP 5804, 31505 Toulouse Cedex, France Phone: 561 36 03 03Fax : 561 36 03 00 URL: http:/www.icom- Crta. de Gracia a Manresa Km. 14,750 08190 Sant Cugat del Valles Barcelona, SPAIN Phone: (93) 590 26 7

10、0 Fax : (93) 589 04 46 URL: 2380 116th Avenue N.E., Bellevue, WA 98004, U.S.A. Phone: (425) 454-8155Fax : (425) 454-1509 URL: Phone: (425) 454-7619 Glenwood Centre #150-6165 Highway 17 Delta, B.C., V4K 5B8, Canada Phone: (604) 952-4266Fax : (604) 952-0090 URL: A.C.N. 006 092 575 290-294 Albert Stree

11、t, Brunswick, Victoria, 3056, Australia Phone: 03 9387 0666Fax : 03 9387 0022 URL: .au 6F No. 68, Sec. 1 Cheng-Teh Road, Taipei, Taiwan, R.O.C. Phone: (02) 2559 1899Fax : (02) 2559 1874 TABLE OF CONTENTS SECTION 1 SPECIFICATIONS SECTION 2INSIDE VIEWS SECTION3 DISASSEMBLY INSTRUCTIONS SECTION 4CIRCUI

12、T DESCRIPTION 4 1 RECEIVER CIRCUITS . 4 1 4 2 TRANSMITTER CIRCUITS . 4 4 4 3 PLL CIRCUIT . 4 5 4 4 LOGIC CIRCUITS . 4 6 4 5 REGULATOR CIRCUITS. 4 6 SECTION 5ADJUSTMENT PROCEDURES 5 1 PREPARATION BEFORE SEVICING . 5 1 5 2 PLL ADJUSTMENTS. 5 2 5 3 TRANSMITTER ADJUSTMENTS . 5 4 5 4 RECEIVER ADJUSTMENTS

13、 . 5 8 5 5 SET MODE ADJUSTMENT . 5 6 SECTION 6PARTS LIST SECTION 7 MECHANICAL PARTS AND DISASSEMBLY SECTION 8SEMI-CONDUCTOR INFORMATIONS SECTION 9 BOARD LAYOUTS 9 1 MAIN UNIT . 9 1 9 2 PLL UNIT . 9 2 9 3 LOGIC UNIT . 9 3 9 4 PHONE BOARD. 9 3 9 5 MIC BOARD. 9 3 9 6 VR BOARD . 9 3 9 7 FILTER UNIT. 9 5

14、 9 8 PA UNIT . 9 7 SECTION 10 BLOCK DIAGRAM SECTION 11 WIRING DIAGRAM SECTION 12 VOLTAGE DIAGRAMS SECTION 1SPECIFICATIONS 1 - 1 I GENERAL Frequency coverage: Receive0.03029.999999 MHz*1 Transmit1.8001.999 MHz*23.5003.999 MHz*2 7.0007.300 MHz10.10010.150 MHz 14.00014.350 MHz18.06818.168 MHz 21.00021.

15、450 MHz24.89024.990 MHz 28.00029.700 MHz *1Guaranteed range: 0.529.999999 MHz. *2Varies accoding to version. Mode: USB, LSB, CW, AM, RTTY (FSK) No. of memory Ch.: 101 (99 regular, 2 scan edges) Freq. resolution: 1 Hz Frequency stability: Less than 200 Hz from 1 min. to 60 min. after power ON. After

16、that rate of stability less than 30 Hz/hr at +25C (+77F). Temperature fluctuations 0C to 50C (+32F to +122F) less than 350 Hz. Power supply requirement: 13.8 V DC 15 % (negative ground) Current consumption: Transmitmax. power20.0 A Receivestand-by1.3 A max. audio2.0 A Usable temp. range: 10C to +60C

17、 (14F to 140F) Antenna connector: SO-239 (50 ) Dimensions: 240 (W) 95(H) 239(D) mm (projection not included)9716(W) 334(H) 91332(D) in Weight: 3.8 kg (8 lb 6 oz) ACC connector: 13-pin REMOTE connector: 2-conductor 3.5(d) mm (18) I TRANSMITTER Modulation system: SSBBalanced modulation AMLow level mod

18、ulation Output power: SSB/CW/RTTY/FM2100 W AM240 W Spurious emission: Less than 50 dB below peak out- put power * spurious frequency ; below 30 MHz: 50 dB, above 30 MHz: 60 dB Carrier suppression: More than 40 dB Unwanted sideband suppression: More than 50 dB Mic. connector: 8-pin connector (600 ) K

19、EY connector: 3-conductor 6.5(d) mm (14) SEND connector: Phono (RCA) ALC connector: Phono (RCA) I RECEIVER Receive system: Double-conversion superheterodyne Sensitivity (10 dB S/N): SSB, CW, RTTY0.16 V*1(1.829.999999 MHz) AM13 V (0.51.799999 MHz) 2.0 V*1(1.829.999999 MHz) *1Pre-amp 1 ON Squelch sens

20、itivity: Less than 5.6 V (SSB) Selectivity: SSB, CW, RTTYMore than 2.1 kHz/6 dB Less than 4.5 kHz/60 dB AM More than 6.0 kHz/6 dB Less than 20.0 kHz/40 dB Spurious and image rejection ratio: More than 70 dB (1.829.999999 MHz) Audio output power: More than 2.0 W (at 13.8 V DC)at 10 % distortion with

21、an 8 load RIT variable range: 1200 Hz PHONES connector: 3-conductor 6.5(d) mm (14) EXT SP connector: 2-conductor 3.5(d) mm (18) 8 All stated specifications are subject to change without notice or obligation. 2 - 1 SECTION 2INSIDE VIEWS Filter unitPA unit MAIN unit PLL unit Top view (PA AND FILTER UN

22、ITS) Bottom view (MAIN AND PLL UNITS) Rx RF preamplifier (Q1401, Q1402: 2SK2171) Tx Mixer (Q101, Q102: 3SK131) 1st Lo amplifier (Q201: 2SC4673) Rx 1st mixer circuit (64.455 MHz) DDS gate allay IC (IC6: SC-1245A) Reference oscillator circuit (Q9: 2SC2714, X1: CR-337, 32.000 MHz) +5V Reg. (IC1: TA7805

23、) BFO DDS (IC2: SC-1287) Rx 1st IF amplifier (Q1201: 3SK131) 2nd mixer circuit (D401: HSB88WSTR, Rx; 455 kHz, Tx; 64.455 kHz) Predrive amplifier (Q1: 2SC1971) Tx/Rx switching relay (RL13: AG201344) Drive amplifier (Q2, Q3: 2SC3133) Power amplifier (Q4, Q5: 2SC2904) Tx 1st IF amplifier (Q151: 2SK882)

24、 MIC amplifier (IC2201: PC5023) Tx 455 kHz Modulator (IC2301: MC1495) USB, LSB, CW, RTTY filter (FI611: FL-65) Rx 2nd IF amplifier (Q1301: 3SK131) Tx 2nd IF amplifier (Q502: 2SK882) FAN control-2 (Q3601: 2SD1664) FAN control-1 (IC2101: NJM2058M) SWR detector (L13: LR-391) Tx low-pass filters (L13: L

25、R-391) 3 - 1 SECTION 3DISASSEMBLY INSTRUCTIONS Removing the covers Remove 14 screws from the top and bottom covers. Removing the Front unit Remove 4 screws from the front panel. How to connect the coaxial cable Connect the coaxial cable as shown in below. J6 J3 to MAIN unit PA unit FILTER unit J1 J7

26、01 MAIN unit PLL unit J3 from FILTER unit J6 from PA unit J701 J1 SECTION 4CIRCUIT DESCRIPTION 4 - 1 4-1 RECEIVER CIRCUITS 4-1-1 RF SWITCHING CIRCUIT (FILTER AND MAIN UNITS) The RF switching circuit leads receive signals to bandpass filters from the antenna connector while receiving. While transmitt

27、ing, this circuit leads signals from the RF power amplifier to the antenna connector. This circuit includes a 20 dB RF attenuator circuit to prevent distortion from very strong signals. RF signals from the antenna connector pass through the transmit/receive switching relay (RL13), and low-pass filte

28、r (L14, C14C16), and are then applied to the MAIN unit via J3 (MAIN unit; J701). The signals from the FILTER unit are either bypassed or are attenuated at the 20 dB attenuator (D701, R703). The sig- nals are then applied to RF filters. 4-1-2 RF BANDPASS FILTER CIRCUIT (MAIN UNIT) RF bandpass filters

29、 pass only the desired band signals and suppress any undesired band signals. The RF circuit has 7 RF bandpass filters (BPF) for signals above 1.6 MHz and 1 low-pass filter (LPF) for signals and suppress any undesired band signals. (1) 0.031.6 MHz The signals pass through the low-pass filter (L821, L

30、822, C822C824) to suppress unwanted frequencies. The fil- tered signals are bypassed a pre-amplifier by a BPF control signal (B0) and preamp control signal (PROF), and are then applied to the 1st mixer circuit (Q1101Q1104). (2) 1.62.0 MHz The signals pass through a bandpass filter (L831L833, L835, L

31、836, C831C834, C837C840) to suppress unwant- ed frequencies. The filtered signals are then applied to the pre-amplifier circuit. (3) 2.030.0 MHz The signals pass through a high pass filter (L811L814, C811C817) to suppress excessively strong signals below 2.0 MHz, such as from broadcasting stations.

32、The filtered signals are applied to a low-pass filter and one of 5 band- pass filters depending on their frequencies and are then applied to the pre-amplifier circuit. 4-1-3 PRE-AMPLIFIER CIRCUIT (MAIN UNIT) The pre-amplifier circuit uses two 2SK2171s to obtain 10 dB of gain over a wideband frequenc

33、y range. When the pream- plifier is turned ON, the signals above 1.6 MHz are applied to the pre-amplifier circuit. Q1401 and Q1402 are connected in parallel to easily match the impedance to 50 . IC3003 (pins 11, 12) switches the signals from a bandpass filter, either to be bypassed, or to be applied

34、 to the pre-amplifier, depending on the PREAMP switch condition. Amplified or bypassed signals are applied to the 1st mixer circuit (Q1102Q1104) 4-1-4 1ST MIXER CIRCUIT (MAIN UNIT) The 1st mixer circuit mixes the receive signals with the 1st LO signal to convert the receive signal frequencies to a 6

35、4.455 MHz 1st IF signal. Used RF filter Band 0.031.6 MHz 1.62 MHz 24 MHz 48 MHz Band 811 MHz 1115 MHz 1522 MHz 2230 MHz Control signal B4 B5 B6 B7 Control signal B0 B1 B2 B3 Input diode D80212 D80212 D803 D810 Input diode D804 D811 D805 D812 RECEIVER CONSTRUCTION ANT 1st mixer Q1101Q1104FI301A/B BFO

36、2nd LO1st LO Crystal filter 2nd mixer D401IC2001 64.455 MHz SSB, CW, RTTY Ceramic BPF 455 kHz Ceramic BPF AF selector AM detector to AF amplifier SQL controll AM FI611 SSB-N, CW-N, RTTY-N (OPTION) Crystal BPF 4 - 2 The signals from the pre-amplifier circuit, or signals which bypass the pre-amplifier

37、, pass through a low-pass filter (L902, L903, C902C907). This low-pass filter suppresses signals above 30 MHz to eliminate direct receiving of signals at 64.455 MHz and image interference at 130160 MHz. The signals are then applied to the 1st mixer (Q1102Q1104). The 1st LO signal (64.48594.455 MHz)

38、enters the MAIN unit from the PLL unit via J201 (PLL unit; J4). The LO signal is amplified at Q201 and then applied to the 1st mixer. The 1st mxer (Q1101Q1104) uses four 2SK1740s to pro- duce high level mixing with a high intercept point. 4-1-5 1ST IF CIRCUIT (MAIN UNIT) The 1st IF circuit filters a

39、nd amplifies the 1st IF signals. The 1st IF signals from the 1st mixer circuit are applied to MCF (Monolithic Crystal Filter: Fl301) to suppress out-of-band signals. The passband width of FI301 is 7.5 kHz/6 dB. The filtered signals are applied to the 1st IF amplifier (Q1201). AGC voltage is supplied

40、 to the 2nd gate of Q1201. 4-1-6 2ND MIXER CIRCUIT (MAIN UNIT) The 2nd mixer circuit mixes the amplified 1st IF signals and 2nd LO signal (64.00 MHz) to convert the 1st IF signals into a 2nd IF signal. The amplified 1st IF signals from Q1201 are converted into 455 kHz 2nd IF signal at the 2nd mixer

41、(D401). D401 is a DBM (Double Balanced Mixer). The 2nd LO level is approx. 0 dBm. The 2nd IF signals are applied to FI1301 to suppress unde- sired signals such as the 2nd LO signal, and are then applied to the NB circuit. 4-1-7 NOISE BLANKER CIRCUIT (MAIN UNIT) The noise blanker circuit detects puls

42、e type noise, and turns OFF the signal line when noise appears. The 2nd IF signals from FI1301 are applied to the noise blanker gate (D1301, D1302). A portion of the signals from FI1301 is amplified at the noise amplifiers (Q1501, Q1502, Q1503), then detected at the noise detector (D1501). The detected signal from the noise detector is applied to the noise blanker control (Q1508, Q1509). A portion of the detected signals from the