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1、COMMUNICATIONS RECEIVER iC-r20 SERVICE MANUAL INTRODUCTION DANGER This service manual describes the latest service information for the IC-R20 COMMUNICATIONS RECEIVER at the time of publication. This service manual covers each versions. MODEL IC-R20 VERSION USA, EXP-01, CAN EUR, EXP-02 UK, SEA AC ada

2、pter BC-149A BC-149D ORDERING PARTS Be sure to include the following 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 1110003200S.ICTA31136FNIC-R20 RF UNIT5 pieces 8930062430Key2699 Key

3、boardIC-R20 Chassis12 pieces Addresses are provided on the inside back cover for your convenience. NEVER connect the receiver to an AC outlet or to an exter- nal DC power supply that uses more than 6.3 V.This will ruin the receiver. DO NOT expose the receiver to rain, snow or any liquids. DO NOT rev

4、erse the polarities of the power supply when connecting the receiver. DO NOT apply an RF signal of more than 20 dBm (100 mW) to the antenna connector. This could damage the receivers front end. REPAIR NOTES 1. Make sure a problem is internal before disassembling the receiver. 2. DO NOT open the rece

5、iver until the receiver 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 turning tool MUST be used for all adjustments. 5. DO NOT keep power ON for a long time when the

6、receiver is defective. 6. READ the instructions of test equipment thoroughly before connecting equipment to the receiver. To upgrade quality, any electrical or mechanical parts and internal circuits are subject to change without notice or obligation. Icom, Icom Inc. andare registered trademarks of I

7、com Incorporated (Japan) in the United States, the United Kingdom, Germany, France, Spain, Russia and/or other countries. SECTION1SPECIFICATIONS SECTION2INSIDE VIEWS SECTION3DISASSEMBLY INSTRUCTIONS SECTION4CIRCUIT DESCRIPTION 4-1RECEIVER CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . .

8、. . . . . . . . . . . . . . . . . 4 - 1 4-2PLL CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 7 4-3OTHER CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 10 4-4POWER SUPPLY CIRCUITS.

9、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 11 4-5PORT ALLOCATIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 12 4-6BC-156 CIRCUIT DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 14 S

10、ECTION5ADJUSTMENT PROCEDURES 5-1PREPARATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 1 5-2SOFTWARE ADJUSTMENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 3 SECTION6PARTS LIST SECTION7MECHANICAL PARTS AND

11、DISASSEMBLY SECTION8SEMI-CONDUCTOR INFORMATION SECTION9BOARD LAYOUTS 9-1RF UNIT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 - 1 9-2LOGIC UNIT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12、. . . . 9 - 3 9-3REC UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 - 5 9-41STAVCO BOARD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 - 7 9-51STBVCO BOARD . . . . . . . . . . . . . . . .

13、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 - 7 9-62NDCVCO BOARD. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 - 7 9-72NDDVCO BOARD. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 - 7 9-8DOW

14、NCONV BOARD. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 - 7 SECTION10BLOCK DIAGRAM SECTION11VOLTAGE DIAGRAM 11-1 RF UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 - 1 11-2 LOGIC UNIT . . . .

15、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 - 3 11-3 REC UNIT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 - 4 11-4 1STAVCO BOARD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

16、 . . . . . . . . . . . . . . . 11 - 5 11-5 1STBVCO BOARD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 - 5 11-6 2NDCVCO BOARD. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 - 6 11-7 2NDDVCO BOARD. . . . . . .

17、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 - 6 11-8 DOWNCONV BOARD. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 - 7 SECTION12BC-156 BATTERY CHARGER UNIT 12-1 DISASSEMBLY INFORMATION . . . . . . . . . . . . . . . . . . .

18、. . . . . . . . . . . . . . . . 12 - 1 12-2 BC-156 BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 - 1 12-3 BC-156 VOLTAGE DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 - 2 12-4 BC-156 BOARD LAYOUTS . . . . . . . .

19、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 - 3 TABLE OF CONTENTS 1 - 1 SECTION 1SPECIFICATIONS IC-R20 MGENERAL Frequency coverage: Mode: FM, WFM, AM, SSB, CW No. of memory channel: 1250 channel (incl. scan edge and auto memory write ch.) Frequency stability: 6 ppm max. Tuning

20、steps: 0.01, 0.1, 1, 5, 6.25, 8.33*, 9*, 10, 12.5, 15, 20, 25, 30, 50 and 100 kHz *selectable depending on the operating frequency band. Antenna Impedance: 50 Power supply requirement: 3 AA(R6) alkaline cells, BP-206 or external power supply (BC-149/A/D, CP-18) Polarity: Negative ground Current drai

21、n (at 3.7 V, backlight is OFF) : Rated audio150 mA typical Standby100 mA typical Power saved35 mA typical (Power save ratio is 1 : 4) Usable temperature range: 10C to +60C ( 14F to +140F) Dimensions: 60(W) 142(H) 34.8(D) mm; (projections not included)238(W) 51932(H) 138(D) in Weight (with antenna an

22、d BP-206): Approx. 320 (g); 111932(oz) External SP connector: 3-conductor 3.5(d) mm (18”) / 8 Audio output power (at 3.7 V) : 100 mW typical at 10 % distortion with an 8 load BP-206 charging time: Approx. 8 hours Charging current: 400 mA typical MRECEIVER Receiver system: Triple super heterodyne and

23、 down convertor Intermediate frequency : 1st266.7 and 429.1 MHz 2nd19.65 MHz 3rd450 kHz Sensitivity* : Single mode receiving; Except spurious point (Unit; V) *FM and WFM is measured at 12 dB SINAD. AM, SSB and CW are measured at 10 dB S/N. Squelch Sensitivity: (except spurious points) Selectivity: S

24、SB/CWMore than 1.8 kHz / 6 dB AM / FMMore than 12 kHz / 6 dB Less than 30 kHz / 60 dB WFMMore than 150 kHz / 6 dB All stated specifications are subject to change without notice or obligation. Version EUR, UK, SEA, CAN EXP-01, EXP-02 USA FRA Receive coverage (MHz) 0.1503304.999 0.150821.999, 851.0008

25、66.999, 896.0001304.999, 1305.0003304.999 0.15029.999, 50.20051.200, 87.500108.000, 144.000146.000 430.000440.000, 1240.0001300.000 Frequency (MHz) 0.495 1.619 1.620 4.999 5.000 29.999 30.000 49.999 50.000 53.999 54.000 75.999 76.000 108.000 108.001 117.999 118.000 135.999 136.000 146.999 147.000 17

26、4.999 175.000 221.999 330.000 469.999 470.000 769.999 770.000 832.999 833.00 1304.999 1330.000 2304.999 2330.000 2999.999 FM 0.56 0.4 0.56 0.71 5.6 18 WFM 1.8 1.8 2.5 AM 2.2 1.4 1.4 SSB/CW 0.4 0.25 0.25 0.25 0.32 Frequency (MHz) 0.495 1.619 1.620 4.999 5.000 29.999 30.000 75.999 76.000 108.000 108.0

27、01 117.999 118.000 135.999 136.000 174.999 175.000 221.999 330.000 469.999 470.000 769.999 770.000 832.999 833.000 1304.999 1330.000 2304.999 2333.000 2999.999 FM 0.56 V 0.4 V 0.56 V 0.71 V 5.6 V 18 V WFM 18 V 18 V 18 V AM 2.2 V 1.4 V 1.4 V 1 - 2 BC-156 Input voltage: 8.016.0 V Charging current: 0.9

28、61.44 A (Rapid charging) Usable temperature: 0C to +35C (+32F to +95F) Timer device: 192288 minutes (Rapid charging) 1218 minutes (Reserve charging) Protect function: FUNCTIONBP-206 CONDITIONBC-156 ACTIONLED CONDITION Over dischargeBecomes 1.5 VCharging stopBlinking orange Over chargeBecomes 4.5 VCh

29、arging stopBlinking orange OvercurrentShorten BP-206 and GNDCharging stopBlinking orange Full chargeBecomes 4.2 VCharging stopLighting green Normal chargingBecomes 3.5 VChargingLighting orange 2 - 1 SECTION 2INSIDE VIEWS 2-1 RF UNIT Top view Bottom view Highpass filter circuit (C854, C856, C858) 470

30、833 MHz RF amplifier (Q24: 2SC5008) 1G RF amplifier (Q26: 2SC5624) B-BAND RF amplifier (IC18: PC2746TB) B-BAND 1st mixer (IC15: PC2757TB) B-BAND 1st IF filter (266.7 MHz) (FI1: EFCH266MKQP1) B-BAND 2nd mixer (IC16: PC2757TB) SSB AF amplifier (Q532: 2SK1069) SSB IF amplifier 450 kHz (Q531: 2SC4617) B

31、FO mixer (D115, D116: RB876W) B-BAND 3rd Lo amplifier (Q555: 2SC5006) B-BAND 2nd IF amplifier (Q542: 2SC5006) A-BAND IF IC (IC2: TA31136FN) A-BAND 2nd IF amplifier (Q5: 2SC5006) A-BAND 3rd Lo amplifier (Q540: 2SC5006) A-BAND 2nd IF filter (19.65 MHz) (FI3: FL-293) A-BAND 2nd mixer (IC10: PC2757TB) A

32、-BAND 1st IF filter (429.1 MHz) (FI4: EFCH429MKQP4) A-BAND 1st mixer (IC1: PC2757 TB) A-BAND RF amplifier (IC19: PC2757 TB) 30300 MHz RF amplifier (Q36: 2SC5006) A-UHF RF amplifier (Q35: 2SC5006) B-UHF RF amplifier (Q548: 2SC5006) Lowpass filter circuit (L123L125) A/B-UHF (pre-amplifier (Q551: PA805

33、T) PLL reference oscillator circuit Oscilktes 19.200 MHz B-BAND FM IF IC (IC17: TA31136FN) X1: CR-593, D171: HVC350B Q556: 2SC4617 B-BAND AM detector and AGC amplifier (Q545: XP6501) A-BAND AM detector and AGC amplifier (Q4: XP6501) A/B-VHF pre-amplifier (Q550: FH102) A-VHF A-band RF amplifier (Q14:

34、 2SC5006) MF/HF-L/HF-H RF amplifier circuit Q505: 2SC4226, D163, D164: MA2S728 B-BAND IF amplifier (Q544: XP6501) A-BAND IF amplifier (Q1: XP6501) DOWNCONV BOARD 1STBVCO BOARD 1STAVCO BOARD Bar antenna 2NDDVCO BOARD 2NDCVCO BOARD 2 - 2 2-2 LOGIC UNIT Top view Bottom view BFO circuit IC6: SN74AHC1GU0

35、4DBVR X2: CSBFB543K AF amplifier regulator (Q7: XP1501 Q9: 2SB1132) AF amplifier (IC15: TA31056F Q8: 2SA1588) AF pre-amplifiers (Q12, Q16: 2SC4617) +3 regulators (Q10, Q15: 2SA1362) Reset IC (IC2: BD5228G) Main CPU (IC3: M30620MCP-129GP OTHER, M30620MCP-130GP USA) B-BAND AF circuit Q24: XP6501, Q27:

36、 2SJ144, Q22: 2SC4617, IC7: SM6451B A-BAND AF circuit Q25: XP6501, Q26: 2SJ144, Q23: 2SC4617, IC7: SM6451B +3V reg. (Q17: 2SA1588) Battery daging regulators (Q30: 2SB1201, Q32: 2SC4617, Q33: 2SB1132) LCD (DS12: M3-0243TIY) +3SC reg. (Q13: XP6501) +3S reg. (Q14: 2SA1588) 3V reg. IC (IC8, IC9: R1111N3

37、21B) Recording/playback IC (IC7: ML2302TB) +3V regulator (IC1: BD5228G, IC10: R1111N321B) Mute (when SQL off) (IC8, IC9: SN74AHC1G66HDBVR) USB interface IC (IC3: FT245BM) Sub CPU (IC2: M30620FCPGP) Flash memory for recording/playback (IC6: K9F5608UOC-YCBO) 2-3 REC UNIT Top view Bottom view SECTION 3

38、DISASSEMBLY INSTRUCTIONS (1) REMOVING THE REAR PANEL q Unscrew 4 screws, A (2 115 mm, black). w Unscrew 2 screws, B (2 8 mm, black). e Unplug W1 and J8 (LOGIC unit) to separate the front and the rear panels. (3) REMOVING THE REC UNIT q Unscrew 4 flat-head screws, H (2 4 mm, silver). w Unsolder 1 poi

39、nt, I. e Remove the REC unit in the direction of the arrow. (4) REMOVING THE RF UNIT q Unscrew 3 flat-head screws, J (2 4 mm, silver). w Unsolder 2 points, K. e Remove the RF unit in the direction of the arrow. Front panel Rear panel LOGIC unit Speaker W1 J8 A B H I REC unit RF unit J K K J1 LOGIC u

40、nit J5 C D E F G (2) REMOVING THE LOGIC UNIT q Remove 2 knobs, C, and unscrew 2 nuts, D. w Unscrew 2 flat-head screws, E (2 4 mm, silver), and 1 pan-head screw, F (2 4 mm, black). e Unsolder 10 points, G. r Unplug J5 (bottom side of LOGIC unit) and J1 (RF unit) to separate the LOGIC unit. t Remove t

41、he LOGIC unit in the direction of the arrow. 3 - 1 4 - 1 4-1 RECEIVER CIRCUITS 4-1-1 BAND SWITCHING CIRCUIT (RF UNIT) The RF signals from the antenna connector pass through the limiter (D68) and an attenuator* (D69). The signals are then applied to the antenna switching circuit (D3, D11, D13, D65, D

42、66 and D73D75 ). *Above 2 GHz RF signals do not pass through the attenua- tor. 4-1-2 RF CIRCUIT (RF UNIT) The RF circuit amplifies the received signals within the range of frequency coverage and filters out-of-band signals. A-BAND CIRCUIT (1) MF (above 0.15 MHz, below 1.9 MHz) signals RF signals (0.

43、151.9 MHz) from an attenuator (D69) pass through the low-pass filter (L123L125 and C851C853), band switch (D66) and another low-pass filter (L88, L89, C533C535, C657, C658). The filtered signals pass through another band switch (D67), and are then amplified at an RF amplifier (Q505). The amplified s

44、ignals are applied to the next band switch (D72). (2) HF-L (above 1.9 MHz, below 15 MHz) signals RF signals (1.915 MHz) from an attenuator (D69) pass through the low-pass filter (L123L125 and C851C853), band switch (D65) and bandpass filter (L85L87, L91, C522C531 and C891). The filtered signals pass

45、 through another band switch (D70), and are then amplified at an RF amplifier (Q505). The amplified signals are applied to the next band switch (D72). SECTION 4CIRCUIT DESCRIPTION RF RF BPF BPF BPF RF BPF BPF Pre Amp Pre Amp HF-L (1.9 15 MHz) MF (15 30 MHz) A-VHF (118 175 MHz) B-VHF (118 175 MHz) 30

46、 300M (30 300 MHz except A-VHF range) A-UHF (300 470 MHz) 800M (470 833 MHz) 1G (833 1305 MHz) B-UHF (300 470 MHz) MF (0.15 1.9 MHz) from the bar antenna HPF HPF LPF LPF LPF LIMITER BAND SW BAND SW BAND SW BAND SW BAND SW BAND SW BAND SW ANTENNA ATT ANT SW to 2nd mixer circuit RF-A circuit RF-B circ

47、uit 1st mixer 1st mixer to 2nd mixer circuit LO (1001 or 2002MHz) RF IC2IC3 mixer 1305 3305 MHz RF RF BPF RF BPFRF BPF RF RF RF BPF BPF HPF Q505 Q36 Q550 Q14 Q549 Q551 Q35 Q548 Q24 Q25 IC18 IC15 IC1 IC19 RF CIRCUITS 4 - 2 (3) HF-H (above 15 MHz, below 30 MHz) signals RF signals (1530 MHz) from an at

48、tenuator (D69) pass through the low-pass filter (L123L125 and C851C853), band switch (D73) and bandpass filter (L81L84 and C511C520). The filtered signals pass through another band switch (D64), and are then amplified at an RF amplifi- er (Q505). The amplified signals are applied to the next band sw

49、itch (D72). (4) A-VHF (above 118 MHz, below 175 MHz) signals RF signals (118175 MHz) from an attenuator (D69) pass through the low-pass filter (L123L125 and C851C853), band switch (D74), and are then applied to the pre-amplifier (Q550) which is controlled by “A_VHF3V” signal via the D148. The signals are amplified at the RF amplifier (Q14), and pass through the bandpass filter (D1, D2, L1 and C14C16). The filtered signals are