IC-T70A_E_serv.pdf

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1、S-14623XZ-C1 Feb. 2010 VHF/UHF DUAL BAND FM TRANSCEIVER This service manual describes the latest technical information for the IC-T70A and IC-T70E VHF/UHF DUAL BAND FM TRANSCEIVER, at the time of publication. NEVER connect the transceiver to an AC outlet or to a DC power supply that uses more than t

2、he specified voltage. This will ruin the transceiver. DO NOT expose the transceiver to rain, snow or any liquids. DO NOT reverse the polarities of the power supply when connecting the transceiver. DO NOT apply an RF signal of more than 20 dBm (100 mW) to the antenna connector. This could damage the

3、transceivers front-end. To upgrade quality, any electrical or mechanical parts and internal circuits are subject to change without notice or obligation. MODELVERSION SUPPLIED BATTERY PACK SUPPLIED CHARGER IC-T70A TPE BP-264 BC-167SA USA KOR AUSBC-167SV EXPBC-167SA EXP-01BC-167SD IC-T70E EURBC-167SD

4、UK CHN RSPBP-264BC-167SD Be sure to include the following four points when ordering replacement parts: 1. 10-digit Icom part number 2. Component name 3. Equipment model name and unit name 4. Quantity required 1110007320 NJM2591V IC-T70A MAIN UNIT 2 pieces 8310075430 3253 WINDOW PLATE IC-T70E CHASSIS

5、 10 pieces Addresses are provided on the inside back cover for your convenience. ORDERING PARTS 1. Make sure that the problem is internal before disassembling the transceiver. 2. DO NOT open the transceiver until the transceiver is disconnected from its power source. 3. DO NOT force any of the varia

6、ble 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. 6. DO NOT transmit power into a Standard Signal Generator or a Sweep

7、Generator. 7. ALWAYS connect a 50 dB to 60 dB attenuator between the transceiver and a Deviation Meter or Spectrum Analyzer, when using such test equipment. 8. READ the instructions of the test equipment throughly before connecting it to the transceiver. REPAIR NOTES INTRODUCTION CAUTION (IC-T70A) U

8、NIT ABBREVIATIONS: AC: ACCESSORY CH: CHASSIS M: MAIN UNIT Icom, Icom Inc. and the Icom logo are registered trademarks of Icom Incorporated (Japan) in Japan, the United States, the United Kingdom, Germany, France, Spain, Russia and/or other countries. TABLE OF CONTENTS SECTION 1 SPECIFICATIONS SECTIO

9、N 2 INSIDE VIEWS SECTION 3 DISASSEMBLY INSTRUCTION SECTION 4 CIRCUIT DESCRIPITON 4-1 RECEIVER CIRCUITS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1 4-2 TRANSMITTER CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10、 . . . . . . . . . . . . . . . . . . . . . . . 4-2 4-3 FREQUENCY SYNTHESIZER CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3 4-4 CPU PORT ALLOCATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

11、-4 4-5 VOLTAGE BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4 SECTION 5 ADJUSTMENT PROCEDURES 5-1 PREPARATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12、 . 5-1 5-2 TRANSMIT ADJUSTMENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3 5-3 FREQUENCY ADJUSTMENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7 5-4 MODURATION ADJUSTMENTS. . . . .

13、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8 5-5 RECEIVE ADJUSTMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-11 SECTION 6 PARTS LIST SECTION 7 MECHANICAL PARTS SECTION 8 BOARD LAYOUTS SECTI

14、ON 9 BLOCK DIAGRAM SECTION 10 VOLTAGE DIAGRAM 1 - 1 SECTION 1. SPECIFICATIONS Frequency coverage : (unit: MHz) Version TXRX EUR, KOR 144146, 430440 144146, 430440 UK, RSP 144146, 430440 136174*1, 400479*2 U.S.A. 136174*3, 400479*4 136174*3, 400479*4 TPE 144146, 430432 144146, 430432 AUS 144148, 4204

15、50*2 136174*3, 400479*2 CHN, EXP 136174*3, 400470*2 136174*3, 400479*2 *1Guaranteed 144146 MHz only, *2Guaranteed 430440 MHz only, *3Guaranteed 144148 MHz only, *4Guaranteed 440450 MHz only Mode : FM, FN-N No. of memory channels : 302 (incl. 50 scan edges and 2 call channels) Usable temp. range : 20

16、C to +60C; 4F to +140F Tuning steps : 5, 10, 12.5, 15, 20, 25, 30, 50, 100, 125 and 200 kHz Frequency stability : 2.5 ppm (20C to +60C; 4F to +140F) Power supply : 10.016.0 V DC for external DC power, or specifi ed Icoms battery pack Current drain (at 7.2 V DC) : TX High (typical) VHF 1.7 A, UHF 2.1

17、 A Mid. (typical) VHF 1.2 A, UHF 1.5 A Low (typical) VHF 0.6 A, UHF 0.8 A Rx Max. output Less than 450 mA (Internal speaker) Less than 300 mA (External speaker) Power save Less than 40 mA (Duty 1:8) standby Less than 90 mA Antenna connector : SMA (50 ?) Dimensions : 58(W)111(H)30(D) mm; (projections

18、 not included) 2932(W)438(H)1316(D) in Weight (approx.) : 380 g; 13.4 oz (with antenna and BP-264) Modulation system : Variable reactance freq. modulation Output power (at 7.2 V DC) : (typical) High 5.0 W, Mid. 2.5 W, Low 0.5 W Max. frequency deviation : 5.0 kHz (FM wide: approx.) 2.5 kHz (FM narrow

19、: approx.) Spurious emissions : Less than 60 dBc at High/Mid. Less than 13 dBm at Low Ext. mic. impedance : 2.2 k? D Receiver Receive system : Double-conversion superheterodyne Intermediate frequencies : 1st 46.35 MHz, 2nd 450 kHz Sensitivity (except spurious points, 1 kHz/3.5 kHz Dev.; 12 dB SINAD)

20、 : Guaranteed freq. range Less than 0.18 V Other freq. range Less than 0.32 V Squelch Sensitivity (except spurious points, 1 kHz/3.5 kHz Dev.) : Guaranteed range Less than 0.18 V Other frequency range Less than 0.32 V Audio output power : (at 10% distortion/7.2 V DC) Internal speaker More than 700 m

21、W with a 16 ? load External speaker More than 400 mW with an 8 ? load Selectivity : (at CH spacing 20 kHz/in the amateur bands) FM (Wide) More than 60 dB FM (Narrow) More than 60 dB Ext. speaker connector : 3-conductor 3.5(d) mm; (18)/8 ? Spurious and image rejection ratio (in guaranteed freq. range

22、) : More than 60 dB All stated specifi cations are subject to change without notice or obligation. All stated specifi cations are subject to change without notice or obligation. P GENERALP TRANSMITTER P RECEIVER 2 - 1 SECTION 2. INSIDE VIEWS MAIN UNIT (TOP VIEW) 5 V REGULATOR (5VS line) (Q108) 5 V R

23、EGULATOR (BTL5V line) (Q6) MIC AMP/VOX AMP (IC800) MIC MUTE SW (IC909) AF AMP/BPF/LPF (IC2) RX AF MUTE SW (IC904) TONE FILTER (Q10) AF BPF (Q8) YGR AMP (Q502) TX DRIVE AMP (Q503) TX PWR AMP (Q507) PLL IC (IC305) MODULATION MUTE SW (Q307) DC SW (VCC line) (Q100) 5 V REGULATOR (T5 line) (Q200) D/A CON

24、VERTER (IC5) 5 V REGULATOR (R5 line) (Q202) TX AMP BIAS CONTROLLER (IC500) 3.6 V REGULATOR (IC304) TCXO (X300) TX AMP CURRENT DETECTER (IC102) 2 - 2 MAIN UNIT (BOTTOM VIEW) RF AMP (UHF band) (Q511) RF AMP (VHF band) (Q505) TX AMP BIAS CONTROLLER (IC501) VCO CPU RESET IC (IC200) POWER SUPPLY LINE “BT

25、L5V” SW (Q5) IF DEMODULATOR IC (IC311) 2ND IF FILTER (FI300) DISCRIMINATOR (X301) ELECTRIC VOLUME (IC4) 1ST MIXER (UHF band) (Q509) TX MUTE SW (Q504) DATA LINE BUFFER (Q11) POWER SUPPLY LINE “CHG” SW (Q101) MIC LINE SW (Q7) 1ST IF FILTER (FI301) DATA LINE BUFFER (Q1) POWER SUPPLY LINE “5VS” SW (Q109

26、) 1ST IF MIXER (VHF band) (Q500) CPU (IC907) 5 V REGULATOR (CPU5V line) (IC101) EXPANDER (IC908) EEPROM (IC201) TONE LPF (Q204) ANT SW DRIVER (Q508) AF POWER AMP (IC1) 3 - 1 SECTION 3. DISASSEMBLY INSTRUCTION 1. REMOVING THE CHASSIS 1) Remove the jack cap, ANT nut and 2 knobs. 4) CAREFULLY lift the

27、chassis out of the FRONT PANEL and turn it over in order to unplug the speaker wire. 2) Remove 2 screws from the bottom of the CHASSIS. 3) Lift the bottom of the CHASSIS up in the direction of the arrow. 2. REMOVING THE MAIN UNIT 1) Remove the metal sheet from the top plate. 2) Unsolder the 5 points

28、, and remove the shield plate. KNOBS JACK CAP ANT NUT Remove with; “ICOM Driver (Q)” (8960000370) FRONT PANEL SPEAKER WIRE CHASSIS SHIELD PLATE SCREWS UNSOLDER Solder remover UNSOLDER Solder remover Top plateMetal sheet CHASSIS MAIN UNIT SCREWS SCREWS CHASSIS LCD DIAL NUT TOP PLATE TOP SEAL MAIN UNI

29、T UNSOLDER Solder remover Remove with; “ICOM Driver (AG)” (8960000560) FRONT PANEL SCREWS CHASSIS Suction lifter Part name : EA950R-2 Manufacture : ESCO CO.LTD BE CAREFUL to not pull out the speaker wire when separating the CHASSIS and the FRONT PANEL. 3) Remove the 2 screws from the MAIN UNIT. 4) R

30、emove the top seal, dial nut and top plate from the chassis. 5) Unsolder the 2 points. 6) Remove the 4 screws, and remove the MAIN UNIT from the chassis. For easy separation of the CHASSIS Use a suction lifter to lift the bottom of the CHASSIS up. 4 - 1 DUPLEXER AND RF CIRCUITS 1ST IF CIRCUITS SECTI

31、ON 4. CIRCUIT DESCRIPTION LPF ANT SW ANT SW HPF RF AMP BPF RF AMP BPFBPF BPF LPFLPF LPF 400-479 MHz D510, D511 Q511 VHF (136-174 MHz) D512,D515,D519 D502,D503,D504 D523 UHF(400-479 MHz) To the 1st IF circuits To the 1st IF circuits Q505 D509, D506, UHF TX circuits VHF TX circuits D524 136-174 MHz Du

32、plexer BPF XTALIF AMP VHF LO signal UHF LO signal Q509 Q500 From the VHF RF circuits From the UHF RF circuits VHF 1st mixer UHF 1st mixer Q318 46.35MHz To the 2nd IF circuits LIMIT FI301 D313 4-1 RECEIVER CIRCUITS DUPLEXER The VHF/UHF RX signal from the antenna is separated by frequency in the duple

33、xer. The VHF signal is passed through the LPF, which eliminates the unwanted VHF and above frequencies, and the UHF signal is passed through the HPF, which eliminates the frequencies below UHF. RF CIRCUITS VHF BAND The VHF RX signal from the duplexer is passed through the LPF, ANT SW (D509D511) and

34、BPF, and then applied to the low-noise RF AMP (Q505). The amplified signal is filtered by the 3-stage tuned BPF (D502D504) to thoroughly eliminate unwanted frequencies. (e.g. the image frequencies, etc.). The filtered RX signal is then applied to the 1st IF circuits. UHF BAND The UHF RX signal from

35、the duplexer is passed through two LPFs, ANT SW (D506, D524) and tuned BPF (D523), and then applied to the low-noise RF AMP (Q511). The amplified signal is filtered by the tuned BPF (D512, D515, D519) to thoroughly eliminate unwanted frequencies. The filtered RX signal is then applied to the 1st IF

36、circuits. 1ST IF CIRCUITS The signal from the RF circuits is applied to the 1st IF mixer (VHF band; Q500/UHF band; Q509) and mixed with the 1st LO signal from the VHF/UHF VCO, resulting in the 46.35 MHz 1st IF signal. The 1st IF signal is filtered by the crystal filter (FI301), amplified by the 1st

37、IF AMP (Q318), and then applied to the 2nd IF circuits through the limiter (D313). 4 - 2 2ND IF CIRCUITS RX AF CIRCUITS BPF CERAMIC IF DEMODULATOR IC DISCRI FI300 IC313 X301 TCXO X300 15.3 MHz45.9 MHz Q305 From the 1st IF circuits To the AF circuits X3 Ext. speaker jack Int. speaker AF AMP LPFD/ABPF

38、 SW MUTE From the demodulator circuit IC4 IC1 Q8IC904 2ND IF AND DEMODULATOR CIRCUITS The signal from the 1st IF circuits is applied to the IF demodulator IC (IC313), which contains the 2nd IF mixer, 2nd IF AMP, FM detector, etc. in its package. The 1st IF signal is applied to the 2nd IF mixer and m

39、ixed with the 2nd LO signal, resulting in the 450 kHz 2nd IF signal. The 2nd LO signal is produced by tripling the 15.3 MHz reference frequency signal that is generated by the reference frequency oscillator (TCXO; X300). The 2nd IF signal is filtered by the crystal filter (FI300) to eliminate unwant

40、ed signals, and amplified by the 2nd IF AMP, and then demodulated by the quadrature detector circuit, which employs a discriminator (X301) as the phase shifter. The demodulated AF signal is applied to the RX AF circuits. RX AF CIRCUITS The demodulated AF signal from the IF demodulator IC (IC313) is

41、passed through the mute SW (IC904), LPF and AF filter (Q8), which de-emphasizes the signal to obtain 6 dB/oct of frequency response. The de-emphasized AF signal is adjusted in level by the D/A converter (IC4), and then applied to the AF power AMP (IC1) to obtain the AF output signal. The amplified A

42、F signal is applied to the internal or external speaker. 4-2 TRANSMITTER CIRCUITS TX AF CIRCUITS The audio signal from the internal or external microphone (MIC signal) is passed through the MIC gain VR (IC4) which adjusts the microphone sensitivity, and then applied to the MIC AMP (IC800B). The ampl

43、ified MIC signal is passed through the MIC mute SW (IC909), HPF, BPF (IC2A) and LPF (IC2D). The filtered MIC signal is applied to the D/A converter (IC5) to be adjusted in level (=deviation). The level-adjusted MIC signal is applied to the modulation circuit as the modulation signal. Int. MIC Ext. M

44、IC JACK HPF LPF BPF MIC MUTE MIC AMP To the modulation circuit MOD IC5 IC2D IC2A D/A converter MIC gain VR IC909 IC800B IC4 BUFF UHF VCO BUFF LO AMP VHF VCO From the TX AF circuits To the TX AMPs Q512 D304-D306 Q311 Q314 Q313 D310D309, D307, Q312 D311,D312D319 LO SW LO SW TX AF CIRCUITS MODULATION C

45、IRCUIT The modulation signal from the TX AF circuits is applied to both of the VHF/UHF VCOs and to the reference oscillator (X300), to frequency-modulate it. The frequency-modulated signal from the VHF/UHF VCOs is applied to the TX AMP circuits through the buffer (Q314/Q313), LO SW (D311/ D312), LO

46、AMP (Q512) and another LO SW (D319), as the TX signal. MODULATION CIRCUITS 4 - 3 FREQUENCY SYNTHESIZER CIRCUITS TRANSMIT AMPLIFIERS The TX signal from the LO SW (D319) is passed through the attenuator (D500 and D501), which continuously adjusts the TX signal in level to keep it constant. The level-a

47、djusted signal is amplified by the YGR AMP (Q502), drive AMP (Q503) and power AMP (Q507) in sequence. The gate voltage of the drive AMP (Q503) is adjusted by the TX power reference voltage from the D/A converter (IC5), depending on the TX power. The output signal of the power AMP (Q507) is passed th

48、rough one of the following paths, depending on its frequency. ATT YGR AMP PWR AMP LPF ANT SW APC CTRL ANT SW DRIVE AMP LPF HPFHPFLPFLPF PWR DET PWR DET LPF From the VCO 136-174 MHz D507,D516 D514,D517 Q507Q503 Q502 D500,D501 IC501B VHF RX circuits(136-174 MHz) UHF band VHF band UHF RX circuits(400-4

49、79 MHz) D509-D511 D506,D524 PSET 400-479 MHz D/A IC5 TX AMPLIFIERS BUFF UHF VCO LPF BUFF PLL IC LO AMP FILTER LOOP VHF VCO ATT ATT LPF LPF BUFF UHF mixer VHF mixer From the modulation circuit IF demodulator IC (2nd mixer) 15.3 MHz 45.9MHz Q512 To the TX AMPs IC305 X300 Q509 Q500 Q305 IC311 LO SW LO SW D304-D306 Q311 Q314 Q313 D307,D309,D310 Q312 D311,D312 Q310 D314 D315 LO SW BUFF 4-3 FREQUENCY SYNTHESIZER CIRCUITS VCO VHF VCO The VHF VCO is composed of Q311, D304D306, and generate