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1、SERVICE MANUAL COMMUNICATIONS RECEIVER INTRODUCTION DANGER ORDERING PARTS REPAIR NOTES This service manual describes the latest service information for the IC-R2 at the time of publication. NEVER connect the receiver to an AC outlet or to a DC power supply that uses more than 3.5 V. Such a connectio

2、n could cause a fire hazard and/or electric. DO NOT expose the receiver to rain, snow or any liquids. DO NOT reverse the polarities of the power supply when connecting the receiver. DO NOT apply an RF signal of more than 20 dBm (100mW) to the antenna connector. This could damage the re- ceivers fron

3、t end. 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 8930046581LCD ContactIC-R2LOGIC UNIT5 pieces 8810009560 ScrewPH BO M2x6 ZKIC-R2Chassis10 pieces

4、Addresses are provided on the inside back cover for your convenience. 1. Make sure a problem is internal before disassembling the receiver. 2. DO NOT open the receiver until the receiver is disconnected from its power source. 3. DO NOT force any of the variable components. Turn them slowly and smoot

5、hly. 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 receiver is defective. 6. READ the instructions of test equipment thoroughly before connecting equipment to the receiver. To upgrade qua

6、lity, all electrical or mechanical parts and internal circuits are subject to change without notice or oblig- ation. MODEL IC-R2 VERSION Europe Italy Taiwan U.S.A. Canada Other SYMBOL EUR ITA TPE USA CAN OTH OTH-1 SECTION1SPECIFICATIONS SECTION2INSIDE VIEWS SECTION3DISASSEMBLY INSTRUCTIONS SECTION4C

7、IRCUIT DESCRIPTION 4-1RECEIVER CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-1 4-2PLL CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-3 4-3POWER SUPPL

8、Y CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-4 4-4PORT ALLOCATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-4 SECTION5ADJUSTMENT PROCEDURES 5-1PREPARATION . . . . . . . .

9、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-1 5-2PLL ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-3 5-3RECEIVER ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . .

10、 . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-5 SECTION6PARTS LIST SECTION7MECHANICAL PARTS AND DISASSEMBLY SECTION8SEMI-CONDUCTOR INFORMATION SECTION9BOARD LAYOUTS 9-1LOGIC UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

11、 . . . . .9-1 9-2RF UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-3 SECTION10BLOCK DIAGRAM SECTION11VOLTAGE DIAGRAM 11-1LOGIC UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12、 . . . . . . . . . . . . . . . . . .11-1 11-2RF UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-2 TABLE OF CONTENTS SECTION 1SPECIFICATIONS 1 - 1 MGENERAL Frequency range: Mode: FM, WFM, AM No. of memory channel: 45

13、0 channel Frequency stability: 6 ppm max. (10C to +60) Tuning steps: 5, 6.25, 10, 12.5, 15, 20, 25, 30, 50, and 100 kHz Anntena Impedance: 50 Power supply requirement: 2 AA(R6) Ni-Cd or alka- line cell Polarity: Negative ground Frequency resolution: 5 kHz, 6.25 kHz Current drain (at 3.0 V): Rated au

14、dio170 mA typical Standby100 mA typical Power saved41 mA typical Usable temperature range: 10C to +60C ( 14F to +140F) Dimensions: 58(W) 86(H) 27(D) mm; (projections not included)2932(W) 338(H) 1116(D) in Weight(with antenna and battely): 170 (g); 6 (oz) External SP connector: 3-conductor 3.5(d) mm

15、(18”) / 8 MRECEIVER Receiver system: Tripple super heterodyne Intermediate frequency : 1st266.7 MHz 2nd19.65 MHz 3rd450 kHz Sensitivity* : (except spurious points) * FM and WFM are measured at 12 dB SINAD; AM is measured at 10 dB S/N. Squelch Sensitivity: Selectivity: AM / FMmore than 15 kHz / 6 dB

16、less than 30 kHz / 60 dB WFMmore than 150 kHz / 6 dB Audio output power: 100 mW typical at 10 % distortion with an 8 load All stated specifications are subject to change without notice or obligation. Version EUR, U.K., CAN, OTH, OTH-1 U.S.A. Receive Frequencies (MHz) 0.495 1309.995 0.495 823.995 849

17、.000 868.995 894.000 1309.995 Frequency (MHz) 0.495 1.625 1.625 5.0 5.0 30.0 30.0 76.0 76.0 108.0 108.0 118.0 118.0 136.0 136.0 175.0 175.0 222.0 222.0 247.0 247.0 330.0 330.0 470.0 470.0 770.0 770.0 833.0 833.0 1309.995 FM 0.56 V 0.4 V 0.56 V 0.79 V WFM 1.8 V 1.8 V 2.5 V AM 2.5 V 1.8 V 1.8 V 1.8 V

18、Frequency (MHz) 0.495 1.625 1.625 5.0 5.0 30.0 30.0 76.0 76.0 108.0 108.0 118.0 118.0 136.0 136.0 175.0 175.0 222.0 222.0 247.0 247.0 330.0 330.0 470.0 470.0 770.0 770.0 833.0 833.0 1309.995 FM 0.56 V 0.4 V 0.56 V 0.79 V WFM 5.6 V 5.6 V 5.6 V AM 2.5 V 1.8 V 1.8 V 1.8 V SECTION 2INSIDE VIEWS LOGIC UN

19、IT 2 - 1 RF UNIT AF power amplifier (IC15: TA31056F) AF mute switch (Q37: 2SJ144) AF filter (Q30: XP6501) +3.2 regurater (IC4: S-81332H) 2nd mixer (IC10: PC2757T) IF amplifer (Q5: 2SC5231) FM IF IC (IC2: TA31136FN) PLL circuit PLL IC (IC3: PD3140GS) PLL reference oscillator (X1: CR593 19.200MHz) VCO

20、 circuit 1st mixer (IC1: PC2757T) BOTTOM VIEWTOP VIEW SECTION 3DISASSEMBLY INSTRUCTIONS 3 - 1 REMOVING THE REAR PANEL 1 Unscrew 2 screws, A. 2 Remove the rear panel in the direction of the arrow. REMOVING THE RF UNIT 1 Unscrew 1 screw, B. 2 Remove 1 knob, c. Unscrew 2 nuts, D and E. 3 Unsolder 5 poi

21、nts, F, and then remove the RF unit. REMOVING THE LOGIC UNIT 1 Unscrew 2 screws, G. 2 Unsolder 2 points, H, and then remove the LOGIC unit. A Rear panel B E D C RF unit F H G LOGIC unit SECTION 4CIRCUIT DESCRIPTION 4 - 1 4-1 RECEIVER CIRCUITS 4-1-1 ANTENNA SWITCHING CIRCUIT (RF UNIT) The RF signals

22、from the antenna connector pass through the limitter (D68) and an attenuator (D69). The signals are then applied to the RF circuit the antenna switching circuit (D13, D73, D75) which suppress out-of-band signals. 4-1-2 RF CIRCUIT (RF UNIT) The RF circuit amplifies the received signals within the ran

23、ge of frequency coverage and filters out-of-band signals. (1) 0.495 MHz29.999 MHz RF signals (0.49529.999MHz) from an antenna switching circuit (D73) pass through a low-pass filter (C511C515, L81, L82). The filtered signals are amplified at an RF ampli- fier (Q505) passing through each band-pass fil

24、ter depending on the receiving frequency. The amplified signals are then applied to the 1st mixer circuit (IC1) after being amplified at another RF amplifier (IC11) via the band switching diode(D71). The signals below 1.9 MHz pass through a low-pass filter (C534, C535, C657, C658, L88, L89) via the

25、band switching diode (D66), and are then applied to the RF amplifier circuit (Q505) via the band switching diode (D67). The 1.9 MHz14.995 MHz signals pass through the band switching diode (D65) and band-pass filter (C522C531, L85L87, L91), and are then applied to the RF amplifier cir- cuit (Q505) vi

26、a the band switching diode (D70). The 15 MHz29.995 MHz signals pass through the band switching diode (D63) and high-pass filter (C516C520, L83, L84) and are then applied to the RF amplifier circuit (Q505) via the band switching diode (D64). (2) 118 MHz174.995 MHz, 330 MHz832.995 MHz RF signals (118

27、MHz174.995 MHz, 330 MHz832.995 MHz) from an antenna switching diode (D75) are passed through each bandpass filter and RF amplifier, and are then applied to the 1st mixer circuit (IC1) via the band switching diode (D71) and RF amplifier (IC11). The 118 MHz174.995 MHz signals pass through the band swi

28、tching diode (D74) and low-pass filter (C8C13, C67, C416, L14, L57L59, L70), and are then amplified at RF amplifier (Q14). The amplified signal passes through the tunable band-pass filters (D1, D2) and band switching diode (D25). The 330 MHz469.995 MHz signals are amplified at RF amplifier (Q35) via

29、 the band switching diode (D3) and band- pass filter (C19C23, C216, L2L5). The amplified signal passes through the tunable band-pass filters (D3, D4) and band switching diode (D29). The 470 MHz832.995 MHz signals are amplified at RF amplifier (Q24) via the band-pass filter (C32, C33, C35C37, C39, C1

30、44, C145), between the band switching diode (D11, D32). (3) 30117.995 MHz, 175329.995 MHz The 30 MHz117.95 MHz, 175 MHz329.995 MHz signals pass through the low-pass filter (C40C43, C665, C666, L9, L10, L92), and are then applied to the RF amplifier (Q36). The amplified signals are amplified at the R

31、F amplifier (IC11) via band switching diodes (D34, D71). The amplified signals are applied to the 1st mixer circuit (IC1). (4) 833 MHz1309.995 MHz The 833 MHz1309.995 MHz signals pass through the bandpass filter (C5, C4551, L11L13, L43), and are then applied to the RF amplifier (Q26). The amplified

32、signals are amplified at the RF amplifier (IC11) via band switching diodes (D36). The amplified signals are applied to 1st mixer circuit (IC1). 4-1-3 1ST MIXER CIRCUIT (RF UNIT) The 1st mixer circuit converts the received RF signals to a fixed frequency of the 1st IF signal with a PLL output fre- qu

33、ency. By changing the PLL frequency, only the desired frequency will pass through the bandpass filters at the next stage of the 1st mixer. The filtered RF signals are mixed with 1st LO signals at the 1st mixer circuit (IC1) to produce a 266.7 MHz 1st IF signal. The 1st IF signal is output from pin 6

34、, and passed through the bandpass filter (FI1) to suppress unwanted harmonic components. The filtered 1st IF signal is applied to the 2nd mixer circuit. The 1st LO signals are generated at the 1st VCO (Q28, Q30, D45) and are applied to the 1st mixer (IC1, pin 3) directly or passing through the doubl

35、er circuit (Q31) after being ampli- fied at the buffer amplifiers (IC4, Q40). 4-1-4 1ST IF AND 2ND MIXER CIRCUITS (RF UNIT) The 2nd mixer circuit converts the 1st IF signal to a 2nd IF signal. The filtered 266.7 MHz 1st IF signal from the bandpass filter is mixed with the 2nd LO signal at the 2nd mi

36、xer circuit (IC10, pin 1) to produce a 19.65 MHz 2nd IF signal. The 2nd IF signal pass through (except WFM mode) or bypass (WFM mode) the bandpass filter (FI3), and is then amplified at the 2nd IF amplifier (Q5). The amplified signal is applied to the demodulator circuit. 4-1-5 DEMODULATOR CIRCUITS

37、(RF UNIT) The demodulator circuit converts the 2nd IF signal into AF signals. The 19.65 MHz 2nd IF signal from the 2nd IF amplifier (Q5) is applied to the 3rd mixer section of the FM IF IC (IC2, pin 16) and is then mixed with the 3rd LO signal for conversion into a 450 kHz 3rd IF signal. 4 - 2 IC2 c

38、ontains the 3rd mixer, limiter amplifier, quadrature detector and S-meter detector, etc. A frequency from the PLL reference oscillator is used for the 3rd LO signal (19.20 MHz). (1) FM mode The 3rd IF signal is output from FM IF IC (IC2, pin 3) and passes through the ceramic bandpass filter (FI2). T

39、he fil- tered signal is fed back and amplified at the limiter amplifier section (pin 5), then demodulated AF signals at the quadra- ture detector section (pins 10, 11) and detector coil (L21). The demodulated AF signals are output from pin 9 and are applied to the AF circuit (LOGIC unit). (2) WFM mo

40、de The 3rd IF signal from the 3rd mixer bypasses the ceramic filter (FI2) and fed back to the limiter amplifier section (pin 5). The amplified signal is demodulated at the quadrature detector section (pins 10, 11) and detector coil (L21). The AF signals are output from pin 9 and are applied to the A

41、F cir- cuit (LOGIC unit). By connecting R55 to R54 in parallel, the output character- istics of pin 12, “RSSI”, change gradually. Therefore, the FM IF IC can detect WFM components. (3) AM mode The filtered 3rd IF signal from the bandpass filter (FI2) is amplified at the 3rd IF amplifier (Q1). The am

42、plified IF signal is applied to the AM detector circuit (Q4) to converted into AF signals, and the signals are applied to the AF circuit (LOGIC unit). 4-1-6 AF AMPLIFIER CIRCUIT (LOGIC UNIT) The AF amplifier circuit amplifies the demodulated AF sig- nals to drive a speaker. While in FM mode, AF sign

43、als from the demodulator circuit (RF unit) are passed through the de-emphasis circuit (R118, C66, C68) with frequency characteristics of 6 dB/octave, and are then applied to the pre-amplifier (Q31) via the band- pass filter (Q30). While in AM mode, AF signals are pass through the band- pass filter a

44、nd are then applied to the pre-amplifier (Q31). While in WFM mode, AF signals are applied to the pre- amplifier (Q31) directly. The pre-amplified AF signals pass through the AF mute cir- cuit (Q37) and are then applied to the electronic volume con- trol circuit (IC14, pin 6). The level controlled AF

45、 signals are output from pin 7 and applied to the AF power amplifier (IC15, pin 1) via the buffer amplifier (Q36). The power ampli- fied AF signals are applied to the internal speaker via the EXT SP jack. The electronic volume control circuit controls AF gain, there- fore, the AF output level is acc

46、ording to the VOL setting and also the squelch conditions. 4-1-7 SQUELCH CIRCUIT (LOGIC AND RF UNITS) NOISE SQUELCH The noise squelch circuit cuts out AF signals when no RF signals are received. By detecting noise components in the AF signals, the squelch circuit switches the AF mute switch. A porti

47、on of the AF signals from the FM IF IC (RF unit; IC2, pin 9) are applied to the active filter section (IC2, pin 8). The active filter section amplifies and filters noise components. The filtered signals are applied to the noise detector section and output from IC2 (pin 13) as the “SDET” signal. The

48、“SDET” signal from IC2 (pin 13) passes through the noise detector (LOGIC unit; IC1), and is then applied to the CPU (LOGIC unit; IC11, pin 12) via the “SQL” line. The CPU analyzes the noise condition and outputs the “AMUTE” sig- nal to the AF mute switch (Q37). Even when the squelch id closed, the A

49、F mute switch (Q37) opens at the moment of emitting beep tones. 2nd IF AND DEMODULATOR CIRCUITS Mixer 16 Limiter amp. 3rd IF filter 450 kHz PLL IC IC3 X1 19.2 MHz RSSI IC2 TA31136F 13 2nd IF (19.65 MHz) from Q5 RSSI signal to the CPU pin 7 (Logic unit) 11109 87532 1716 Active filter FI2 Noise detector FM detector LPF Noise comp. SDET signal to the IC11 (Logic unit) 12 R54 R55 C101 C94 R56 C95 C98C99 C96 R57 R58 R60 WFM L21 C93 C242 AF signal WFMS 3rd Q41 4 - 3 TONE SQUELCH The tone squelch circuit detec