Icom_IC-F1610_serv_1998.pdf

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1、SERVICE MANUAL VHF FM TRANSCEIVER iF1610 INTRODUCTION This service manual describes the latest service informa- tion for the IC-F1610 VHF FM TRANSCEIVER. To upgrade quality, any electrical or mechanical parts and internal circuits are subject to change without notice or obligation. DANGER NEVER conn

2、ect 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 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

3、20 dBm (100 mW) to the antenna connector. This could damage the trans- ceivers front end. 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 require

4、d 1110003571 S.ICMC3372SVMIC-F1610 MAIN UNIT5 pieces 8810008660 Screw BT M3x8 NI-ZUIC-F1610 Bottom cover 10 pieces Addresses are provided on the inside back cover for your convenience. REPAIR NOTES 1. Make sure a problem is internal before disassembling the transceiver. 2. DO NOT open the transceive

5、r until the transceiver 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 insu- lated tuning tool MUST be used for all adjustments. 5. DO NOT keep power ON for a long time when th

6、e trans- ceiver is defective. 6. DO NOT transmit power into a signal generator or a sweep generator. 7. ALWAYS connect a 40 dB to 50 dB attenuator between the transceiver and a deviation meter or spectrum ana- lyzer when using such test equipment. 8. READ the instructions of test equipment thoroughl

7、y before connecting equipment to the transceiver. TABLE OF CONTENTS SECTION 1 SPECIFICATIONS SECTION 2INSIDE VIEW SECTION 3DISASSEMBLY AND OPTION INSTRUCTIONS SECTION 4CIRCUIT DESCRIPTION 4 - 1RECEIVER CIRCUITS. 4 - 1 4 - 2TRANSMITTER CIRCUITS. 4 - 2 4 - 3PLL CIRCUITS. 4 - 3 4 - 4POWER SUPPLY CIRCUI

8、TS . 4 - 4 4 - 5PORT ALLOCATIONS . 4 - 5 SECTION 5ADJUSTMENT PROCEDURES 5 - 1PREPARATION . 5 - 1 5 - 2INITIAL SET MODE . 5 - 2 5 - 3PLL ADJUSTMENT. 5 - 3 5 - 4RECEIVER ADJUSTMENT. 5 - 4 5 - 5TRANSMITTER ADJUSTMENT. 5 - 5 SECTION 6PARTS LIST SECTION 7MECHANICAL PARTS AND DISASSEMBLY SECTION 8SEMI-CON

9、DUCTOR INFORMATION SECTION 9BOARD LAYOUTS 9 - 1FRONT UNIT . 9 - 1 9 - 2MAIN UNIT. 9 - 3 SECTION 10BLOCK DIAGRAM SECTION 11VOLTAGE DIAGRAM 11 - 1FRONT UNIT. 11 - 1 11 - 2MAIN UNIT. 11 - 2 All stated specifications are subject to change without notice or obligation. Mesurement method Frequency coverag

10、e Number of channels Type of emission Operating temperature range Power supply voltage Current drain TX max. power (approx.) RX max. audio stand-by Antenna connector Dimensions (proj. not included) Weight Output power Modulation system Max. freqequency deviation Frequency error Spurious emissions Ad

11、jacent channel power Audio frequency response Audio harmonic distortion Residual modulation (with CCITT filter) Limitting Microphone connector Intermediate frequency Sensitivity Squelch sencitivity Adjcent channel selectivity Spurious response Intermoduration Audio frequency response Hum and noise (

12、with CCITT filter) Audio output power External SP connector ETS 300 086 146174 MHz 128 (16 ch 8 banks) 16K0F3E (25 kHz; Wide) 8K50F3E (12.5 kHz; Narrow) 20C to +55C 13.2 V DC (negative ground) 7.0 A 1.2 A 700 mA SO-239 (50 ) 150(W)50(H) 180(D) mm 1.5 kg 25 W Variable reactance frequency modulation 5

13、.0 kHz (Wide) 2.5 kHz (Narrow) 5 PPM 0.25 W 70 dB (Wide) 60 dB (Narrow) +2 dB to 5 dB of 6 dB/octave range from 300 Hz to 3000 Hz (Wide)/2550 Hz (Narrow) 5 % (40 % Dev.) 45 dB minimum: 55 dB typical (Wide) 40 dB minimum: 50 dB typical (Narrow) 70100 % of modulation 8-pin modular (600 ) 1st: 21.75 MH

14、z 2nd: 455 kHz 2 dBV emf (at 20 dB SINAD) 6 dBV emf (Threshold) 70 dB (Wide) 60 dB (Narrow) 70 dB 70 dB typical +2 dB to 5 dB of 6 dB/octave range from 300 Hz to 3000 Hz (Wide)/2550 Hz (Narrow) 45 dB minimum: 55 dB typical (Wide) 40 dB minimum: 50 dB typical (Narrow) 3.5 W at 10% distortion with a 4

15、 load 2-conductor 3.5 (d) mm (18)/4 SECTION 1SPECIFICATIONS 1 - 1 RECEIVERTRANSMITTERGENERAL 2 - 1 SECTION 2INSIDE VIEW MAIN unit Power module* (IC11 : SC-1188) AF power amplifier (IC8 : LA4425A) VCO circuit PLL reference TCXO (X501 : CR-573) PLL IC* (IC12 : MC145190F) D/A converter (IC5 : M62363FP)

16、 FRONT unit CPU (IC20 : HD64F3437F16) EEPROM (IC27 : X25650S8I-2-5) Low-pass filter circuit 1st mixer* (Q2 : 3SK166) RF amplifier* (Q1 : 3SK116) 1st IF filter (FI1 : FL-264) FM IF IC* (IC1 : MC3372SVM) Discriminator (X2 : CDBC455CX16) Microphone amplifier circuit (IC22 : PC5023GR) *Located under sid

17、e of the point SECTION 3DISASSEMBLY AND OPTION INSTRUCTIONS 3 - 1 Opening cover Remove 4 screws from bottom cover. OPC-617 connection Installation location Install option units. OPC-617 ACC CABLE: J4 UT-96 5-TONE UNIT or UT-105 SmarTrunk IITMLogic Board EX-1761 MEMORY EXPANSION UNIT: J7 OPC-822 INTE

18、RFACE CABLE: J501 PIN ASSIGNMENT Break the jack plate using cutting pliers to connect the OPC-617. Pin No. Terminal name DescriptionSpecification 1DIMBacklight control input+5 to +30 V for dark 2PAAF AF output for public address and Ext SP func- tions 0 to 330 mV rms/ 47 k 3DISC AF output for a term

19、inal unit 330 mV rms/100 k 4INAF input for a terminal unit330 mV rms/1200 bps 5PTTPTT control input0 V for transmit 6HORN Grounded when receiving the specified call Less than 50 mA when grounded 7PAAF Ground for PAAF 8DISC Ground for terminal output 9IN Ground for terminal input Connect to J4 Jack p

20、late OPC-617 OPC-822 UT-96 UT-105 EX-1761 15 69 J6 3 - 2 Attach the RMK-1 rear unit attachment to the trans- ceiver main unit using the supplied screws. Remove 4 screws from the attachment to open the front plate. Connect an optional separation cable OPC-609 (1.9 m) to the inside of the front plate

21、and tighten the cable lug using the screw. Re-attach the front plate. RMK-1 connection Remove 3 allen-socket bolts from the front plate using an allen-wrench (1/32 in). Separate the front unit from the transceiver main unit. Remove 4 screws from the RMK-1 front unit attach- ment to open the rear pla

22、te. Connect the other end of the optional separation cable to the atachement and tighten the cable lug using the screw. Re-attach the rear plate. Attach the front unit and attachment with the 3 removed allen-socket bolts. Front plate Supplied screws with the RMK-1 RMK-1 rear unit attachment Separati

23、on RMK-1 front unit attachment Separation cable Rear plate 4 - 1 SECTION 4CIRCUIT DESCRIPTION 4-1 RECEIVER CIRCUITS 4-1-1 ANTENNA SWITCHING CIRCUIT The antenna switching circuit functions as a low-pass filter while receiving and a resonator circuit while transmitting. The circuit does not allow tran

24、smit signals to enter receiver circuits. Received signals enter the antenna connector (J1) and pass through the low-pass filters (L1L3, C2, C3, C8C10). The filtered signals are passed through the 4type antenna switching circuit (D5, D6, L5) and then applied to the RF cir- cuit. 4-1-2 RF CIRCUIT The

25、RF circuit amplifies signals within the range of frequen- cy coverrage and filters out-of-band signals. The signals from the antenna swiching circuit pass through the tunable bandpass filter (D7, L8). The filtered signals are amplified at the RF amplifier (Q1) and then enter the anoth- er three-stag

26、e bandpass filters (D9D11, L12, L13) to sup- press unwanted signals. The filtered signals are applied to the 1st mixer circuit. D7, D9D11 employ varactor diodes, that are controlled by the PLL lock voltage, to track the bandpass filter. These var- actor diodes tune the center frequency of an RF pass

27、 band for wide bandwidth receiving and good image response rejection. 4-1-3 1ST MIXER AND IST IF CIRCUITS The 1st mixer circuit converts the received signal to fixed frequency of the 1st IF signal with the PLL output frequency. By changing the PLL frequency, only the desired frequency will pass thro

28、ugh a pair of crystal filters at the next stage of the 1st mixer. The RF signals from the bandpass filter are mixed with the 1st LO signals, which come from the Rx VCO circuit via the buffer amplifier (Q3), at the 1st mixer circuit (Q2) to produce a 21.75 MHz 1st IF signal. The 1st IF signal is pass

29、ed through the matching circuit (L15, L52) and a pair of crystal filters (FI1) in order to obtain selection capability and to pass only the desired signals. The filtered signal is applied to the 2nd IF circuit after being amplified at the 1st IF amplifier (Q4). 4-1-4 2ND IF AND DEMODULATOR CIRCUITS

30、The 2nd mixer circuit converts the 1st IF signal into a 2nd IF signal. The double-conversion superheterodyne system (which convert receive signals twice) improves the image rejection ratio and obtains stable receiver gain. The 1st IF signal from the IF amplifier (Q4) is applied to the 2nd mixer sect

31、ion of the FM IF IC (IC1, pin 16) and is then mixed with the 2nd LO signal for conversion into 455 kHz 2nd IF signal. IC1 contains the 2nd mixer, 2nd local oscillator, limiter ampli- fier, quadrature detector, active filter and noise amplifier cir- cuit. The local oscillator section and X1 generates

32、 the 21.295 MHz 2nd LO signal. The 2nd IF signal from the 2nd mixer (IC1 pin 3) passes through the ceramic filters (FI3 and FI4) during narrow chan- nel spacing selection or passes through FI4 (bypassing FI3) only during wide channel spacing selection to suppress unwanted heterodyne frequencies sign

33、als via the N/W switches (D501, D502). The filtered signal is applied to the quadrature detector sec- tion in the FM IF IC to demodulate the 2nd IF signal into AF signals using the ceramic discriminator (X2) after being amplified at the limiter amplifier section (pin 5). The demod- ulated AF signals

34、 are output from pin 9 of the IC and applied to the AF circuit via the receiver mute citcuit. The N/W switches (D501, D502) select a ceramic filter (FI3 or bypass), and the other N/W switch (Q61) adjusts the input level to the FM IF IC (IC1, pin 8) to switch the bandwidth depending on the NWC signal

35、 from the CPU (IC20, pins 57) When NWC signal is high, bandwidth setting is wide. 2nd IF and demodulator circuits FI3 2nd IF filter Noise amp. Limiter amp. Quad. detector AF signals +8V X2 Discriminator Mixer X1 21.295 MHz 1st IF from the IF amplifier (Q4) RSSI signal to the CPU (IC20) 875 FI4 31, 2

36、 16139 IC1 MC3372 Active filter 1110 4 - 2 4-1-5 AF AMPLIFIER CIRCUIT The AF amplifier circuit amplifies the demodulated AF sig- nals to drive a speaker. The AF signals from the FM IF IC (IC1, pin 9) are amplified at the AF amplifier (IC2) and are then applied to the high- path filter circuit (IC3a/

37、b). The high-pass filter characteristics are controlled by the HFSW signal from the CPU (IC20, pin 60). When HFSW signal is high, the cut-off frequency is shifted higher to remove CTCSS or DTCS signals. The filtered AF signals from the high-pass filter (IC3, pin 1) are passed through the de-emphasis

38、 circuit (R68, C74) with frequency characteristics of 6 dB/octave, and are then applied to the electronic volume controller (IC7, pin 2) via the AF mute switch (Q6). The output AF signals from the electronic volume controller (IC7, pin 9) are applied to the AF power amplifier (IC8) to drive the spea

39、ker. 4-1-6 RECEIVE MUTE CIRCUITS NOISE SQUELCH A 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. Some noise components in the AF signals from the FM IF IC (IC1, pin 9) are passed th

40、rough the active filter section in the IC (pins 10, 11). The N/W switch (Q62) adjusts the input noise level to the IC between wide and narrow bandwidths. When NWC signal which is applied to Q62 is High, band- width setting is wide. The noise signals from FM IF IC (IC1, pin 11) are passed through the

41、 level controller (IC5, pins 21, 22) and are then converted into the pulse-type signals (NOIS) at the noise detector circuit (Q9, Q10). The NOIS signal from the noise detector (Q10) is applied to the CPU (IC20, pin 32). The CPU then analyzes the noise condition and controls the AMUT (pin 56) and SP

42、(pin 79) ports to toggle the AF mute switches (Q6, Q7). CTCSS AND DTCS The tone squelch circuit detects AF signals and opens the squelch only when receiving a signal containing a matching subaudible tone (CTCSS or DTCS). When tone squelch is in use, and a signal with a mismatched or no subaudible to

43、ne is received, the tone squelch circuit mutes the AF signals even when noise squelch is open. A portion of the AF signals from the AF amplifier (IC2) pass through the low-pass filter (Q503) and are then applied to the CTCSS decoder inside the CPU (IC20, pin 43) via the CDEC line to control the AMUT and SP ports. 4-2 TRANSMITTER CIRCUITS 4-2-1 MICROPHONE AMPLIFIER CIRCUIT The microphone amplifier circuit amplifies audio signals from the microphone, within +6 dB/octave pre-emphasis characteristics, to a level needed for the modulation circuit. AF signals (MIC) from the FRONT