IC-V85_E_T_serv.pdf

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1、S-14315XZ-C1 Jan. 2007 FM TRANSCEVERS This service manual describes the latest service information for the IC-V85, IC-V85E and IC-V85-T FM TRANSCEIVERS at the time of publication. NEVER connect the transceiver to an AC outlet or to a DC power supply that uses more than 8 V. This will ruin the transc

2、eiver. 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 transceivers front end. To upgrade quality, any

3、 electrical or mechanical parts and internal circuits are subject to change without notice or obligation. MODELVERSIONSYMBOL IC-V85 U.S.A. USA USA-2 Export EXP EXP-2 EXP-3 Taiwan TPE TPE-2 KoreaKOR IC-V85E Europe EUR EUR-1 U.K.UK IC-V85-TThailandTHA Be sure to include the following four points when

4、ordering replacement parts: 1. 10-digit Icom parts numbers 2. Component part number and name 3. Equipment model name and unit name 4. Quantity required 1110003491 S.IC TA31136FNG IC-V85 RF UNIT 5 pieces 8820001210 Screw 2438 screw IC-V85 Top cover 10 pieces Addresses are provided on the inside back

5、cover for your convenience. Icom, Icom Inc. and logo are registered trademarks of Icom Incorporated (Japan) in the United States, the United Kingdom, Germany, France, Spain, Russia and/or other countries. ORDERING PARTS 1. Make sure a problem is internal before disassembling the transceiver. 2. DO N

6、OT open the transceiver 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 insulated tuning tool MUST be used for all adjustments. 5. DO NOT keep power ON for

7、 a long time when the transceiver is defective. 6. DO NOT transmit power into a signal generator or a sweep 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 test equ

8、ipment thoroughly before connecting equipment to the transceiver. REPAIR NOTES INTRODUCTION CAUTION CONTENTS SECTION 1 SPECIFICATIONS SECTION 2 INSIDE VIEWS SECTION 3 DISASSEMBLY INSTRUCTION SECTION 4 CIRCUIT DESCRIPITON 4-1 RECEIVER CIRCUITS. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9、. . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1 4-2 TRANSMITTER CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2 4-3 FREQUENCY SYNTHESIZER CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10、. . . 4-3 4-4 POWER SUPPLY CIRCUITS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4 4-5 PORT ALLOCATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4 SECTION 5 ADJUSTMENT P

11、ROCEDURES SECTION 6 PARTS LIST SECTION 7 MECHANICAL PARTS AND DISASSEMBLY SECTION 8 SEMICONDUCTOR INFORMATION SECTION 9 BOARD LAYOUTS SECTION 10 BLOCK DIAGRAM SECTION 11 VOLTAGE DIAGRAM 11-1 LOGIC UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12、. . . . . . . . . . . . . . 11-1 11-2 RF UNIT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-2 SECTION 12 UT-108 (Optional product) 1 - 1 SECTION 1 SPECIFICATIONS M GENERAL Frequency coverage : TX: 144148 MHz/RX

13、: 136174 MHz*1 (USA) TX: 144146 MHz/RX: 136174 MHz*2 (Europe, UK) TX/RX: 144146 MHz (Taiwan, Thailand, Korea) TX/RX: 136174 MHz* (General; LM) *1; Guaranteed: 144148 MHz range only *2; Guaranteed: 144146 MHz range only Type of emission: FM Number of memory channels: 107 (incl. 6 scan edges and 1 cal

14、l) Frequency resolution: 5, 10, 12.5, 15, 20, 25, 30, 50 kHz Antenna connector: BNC (50 ) Operating temperature range: 10C to +60C; +14F to +140F Frequency stability: 2.5 ppm ( 10C to +60C; +14F to +140F) Power supply requirement (negative ground) : Specified Icoms battery pack or 11.0 V 15% externa

15、l DC power Current drain (at 7.2 V DC ; approx.): Receiving80 mA (standby) 30 mA (power save) 250 mA (max. audio) Transmitting2.6 A (at 7 W) 2.0 A (at 4 W) 1.0 A (at 0.5 W) Dimensions (Projections not included): 56(W)110(H)34.4(D) mm; 2 7/32(W)4 1132(H)1 1132(D) in. (with BP-227) Weight (approx.): 3

16、10 g; 12.5 oz. (with BP-227 and antenna) 165 g; 5.8 oz (without battery pack and antenna) M TRANSMITTER Output power (at 7.2 V DC): 5.5 W (High)/4 W (Middle)/0.5 W (Low) Thailand 7 W (High)/4 W (Middle)/0.5 W (Low) Others Modulation system: Variable reactance frequency modulation Maximum frequency d

17、eviation: 5.0 kHz Spurious emissions: Less than 60 dBc Microphone connector: 3-conductor 2.5 (d) mm (110”)/2.2 k M RECEIVER Receive system: Double conversion superheterodyne Intermediate frequencies: 1st: 46.35 MHz, 2nd: 450 kHz Sensitivity: Less than 0.2 V (at 12 dB SINAD) Squelch sensitivity: Less

18、 than 0.16 V (at threshold) Selectivity: More than 55 dB Spurious and image rejection: More than 60 dB Intermodulation: More than 55 dB Audio output power (at 7.2 V DC): More than 0.3 W at 10% distortion with an 8 load External speaker connector: 3-conductor 3.5 (d) mm (18”)/8 All stated specificati

19、ons are subject to change without notice or obligation. 2 - 1 SECTION 2 INSIDE VIEWS LOGIC UNIT RF UNIT (TOP VIEW) RF UNIT (BOTTOM VIEW) AF POWER AMPLIFIER (IC23: TA7368F) LCD DRIVER (IC22: LC75834W) CPU CLOCK (X2: CR-836) CPU (IC8: M30620) TX/RX AF SWITCH (IC4: CD4066BPWR) TX/RX AF LPF (IC3: LMV324

20、IPW) EEPROM (IC7: S24CS64A) REGULATOR (IC12: S-812C50AMC) D/A converter (IC10: M62363FP) VCO PLL IC (IC19: MB15E03SL) Descriminator (X3: JTBM450CX24) IF IC (IC2: TA31136FNG) DC switch (Q4: HAT1026) Power amp. (Q1: RD12MVS1) Drive amp. (Q2: RD01MUS1) 2nd IF filter (FI2: LTWC450E) 3 - 1 SECTION 3 DISA

21、SSEMBLY INSTRUCTION 1. Removing the front panel q Remove the knob A and jack cap B. w Unscrew the Antenna nut and 4 screws C and D. e Disconnect the speaker connector. r Take off the chassis in the direction of the arrow. 3. Removing shield plate q Unscrew 2 screws A. w Unsolder 2 points B, and remo

22、ve the shield plate from the RF UNT. 2. Removing the LOGIC UNIT q Remove the rubber seal and dial nut. w Unscrew 5 screws A. e Disconnect the flat cable from J7. r Remove the LOGIC UNIT from the chassis in the direction of the arrow. Ant. nut Front panel Speaker connector Chassis B C D A J7 Flat cab

23、le Jack plate Dial nut seal Rubber LOGIC UNIT AA A Chassis Shield plate RF UNIT A B 4. Removing the RF UNIT q Unscrew 5 screws A. w Unsolder 4 points B (contact spring). e Unsolder 1 point C (antenna connector), and remove the RF UNIT from the chassis. RF UNIT Chassis B A A C 4 - 1 SECTION 4 CIRCUIT

24、 DESCRIPTION 4-1 RECEIVER CIRCUITS ANTENNA SWITCHING The antenna switching circuit toggles the receive (RX) line and transmit (TX) line. The received signals from the antenna are passed through a two-staged Low-Lass Filter (LPF; L1, L2, C1C5) and then applied to the antenna switch (D1, D2, D8, L15,

25、L58, C52, C76, C516). While transmitting, the voltage on the T5V line is applied to D1, D2 and D8, and these are ON. Thus the TX line is connected to the antenna. Simultaneously, the RX line is connected to the GND to prevent transmit signal entering. While receiving, no voltage is applied to the D1

26、, D2 and D8, and these are OFF. Thus the TX line and the antenna is disconnected to prevent received signals entering. Simultaneously, the RX line is disconnected from the GND and the received signals are passed through the LPF (L15, L58, C52, C76, C516). The fi ltered signals are applied to the RF

27、circuits. RF CIRCUITS (RF UNIT) RF circuits fi lter and amplify the received signals within the frequency coverage. The received signals from the antenna switch are passed through a tuned Bandpass filter (BPF; D9, L16, C81) and applied to the RF amplifier (Q12) that received signals are amplified in

28、 low NF rate. The pass band frequency of the tuned BPF (D9, L16, C81) is adjusted by the tuning voltage “T1” from the D/A converter (IC10, pin 2), to suppress unwanted signals for high selectivity. The amplified received signals are passed through the tuned BPF (D11, D12, L18, C92, C94, C96, C502),

29、limiter (D72) and the tuned BPF (D65, L57, C505, C507), then applied to the 1st mixer (Q13). 1ST IF CIRCUITS (RF UNIT) The received signals are converted into the 1st IF signal, fi ltered and amplifi ed at the 1st IF circuits. The signals from the RF circuits are applied to the 1st mixer (Q13) and c

30、onverted into the fixed frequency of 1st IF signal by mixing with the 1st Local Oscillator (LO) signals from the VCO (Q76, D59D61). By changing the 1st LO frequency, only the desired frequency will pass through a pair of crystal filters at the next stage of the mixer. By changing LO frequency, the f

31、requency of the 1st IF signal is fixed one for the receiving frequency. The converted 1st IF signal is passed through the BPF (FI1) and limiter (D63), then amplified by the 1st IF amplifier (Q14). The amplified 1st IF signal is applied to the IF IC (IC2, pin 16). 2ND IF CIRCUITS (RF UNIT) The 1st IF

32、 signal is converted into the 2nd IF signal and demodulated. The 1st IF signal from the 1st IF circuits are converted into the 2nd IF signal at the 2nd mixer section of the IF IC (IC2), by mixing with the 2nd LO signal which is generated at the reference frequency oscillator (X4) after being passed

33、through the PLL IC (IC19, pins 1, 2) and the tripler (Q81). The converted 2nd IF signal is output from pin 3 and passed through the BPF (FI2) to remove the sideband noise, then applied to the 2nd IF amplifier section in IC2 (pin 5). The amplified 2nd IF signal is then applied to the FM-detector sect

34、ion. The demodulated AF signals are output from pin 9 and applied to the AF circuits. AF CIRCUITS (LOGIC UNIT) The demodulated AF signals from the IF IC are amplified and fi ltered at the AF circuits. AF signals from the 2nd IF circuits are passed through the the HPF (IC3, pins 6, 7), and LPF (IC3,

35、pins 13, 14) via the TX/RX AF switches (IC4, pins 1, 2; 10, 11). The switched AF signals are passed through the D/A converter (RF UNIT; IC10, pins 11, 12) for audio level adjustment. The D/A converter is a level controller IC which adjusts AF signal level according to the control signals (“DATA,” “S

36、TROBE,” “CLOCK”) from the CPU (IC8). The level adjusted AF signals are then applied to the AF power amplifier (IC23, pin 4) to be amplified to obtain rated audio output power. The power-amplified AF signals are output from pin 10, and then drive internal or external speaker. D/A converter (IC10) Mix

37、er RSSI Quadrature detector 23 24 From the 1st IF amplifier (Q14) 16 Noise detector R5V X3 1110 IF IC (IC2) Filter amp. Noise amp. Limiter amp. Demodulated signals to the LOGIC UNIT 2nd IF AND DEMODULATOR CIRCUITS 9 “NOIS” signal to the CPU (LOGIC UNIT: IC8, pin 17) “SD” signal to the CPU (LOGIC UNI

38、T: IC8, pin 90) 1312 Q81 2nd IF filter X4 15.3 MHz 45.9 MHz 2 3 8 735 FI2 PLL IC (IC19) 1 2 4 - 2 SQUELCH CIRCUIT (RF AND LOGIC UNITS) - NOISE SQUELCH - The noise squelch mutes the AF output when no RF signals are received. By detecting noise components (around 30 kHz signals) in the demodulated AF

39、signals, the squelch circuit toggles the mute switch and AF power amplifi er ON and OFF. A portion of the AF signals from the IF IC (RF UNIT; IC2, pin 9) are passed through the D/A converter (RF UNIT; IC10, pins 23, 24) for level adjustment. The level adjusted AF signals are applied to the noise fil

40、ter section (RF UNIT; IC2, pins 7, 8; R86R88, C121, C122) which allows only noise components to pass. The filtered noise components are amplified at the noise amplifier section, and rectified into the DC voltage which is proportional to the noise signal level, at the noise detector section, then out

41、put from pin 13 as the “NOIS” signal. The “NOIS” signal is applied to the CPU (LOGIC UNIT; IC8, pin 17), and the CPU compares the “NOISE” signal and set reference level (squelch threshold level). When the input “NOIS” signal is higher than reference level, the CPU cuts off “AFON” signal (from pin 4)

42、 to the AF power amplifier control circuit (LOGIC UNIT; Q14Q16) to deactivate the AF power amplifier (LOGIC UNIT; IC23). - TONE SQUELCH - The tone squelch circuit detects tone signals and opens the squelch only when receiving a signal containing a matched sub audible tone. When the tone squelch is i

43、n use, and a signal with a mismatched or no subaudible tone is received, the tone squelch circuit mutes the AF signals even when the noise squelch is open. A portion of the demodulated AF signals is passed through the LPF (LOGIC UNIT; Q53) to filters CTCSS/DTCS signal. The filtered signal is applied

44、 to the CPU (LOGIC UNIT; IC8, pin 93). The CPU compares the applied signal and the set CTCSS/DTCS, then the CPU controls the status (“Low” or “High”) of “AFON” signal as “ NOISE SQUELCH.” HPF LPF Pre- emph. 1 6 108 7 IC3 IC3 IC4 “MMUTE” “RMUTE” AF and MIC amp. CIRCUITS Demodulated AF signals From IF

45、 IC (IC2, pin 9) From the microphone AF signals “MICS” RF UNITLOGIC UNIT “AFON” D/A converter IC4 IC10 IC3 AMP 4 11 22 10 IC23 SP 2 43 10 1314 11 12 21 98 VCO 4-2 TRANSMITTER CIRCUITS MICROPHONE AMPLIFIER CIRCUITS (LOGIC UNIT) The AF signals from the microphone (MIC signals) are fi ltered and level-

46、adjusted at microphone amplifi er circuits. Audio signals from the microphone (MC1) are applied to IC3 (pin 10) which combines a microphone amplifier and pre- emphasis circuit. The MIC signals are amplified and filtered to obtain +6 dB/oct of frequency characteristic by IC3. The amplified and emphas

47、ized MIC signals are output from the pin 8, and passed through the splatter filter (IC3, pins 13, 14) which suppresses 3 kHz and higher audio components, via the TX/RX switch (IC4, pins 3, 4; 8, 9). The filtered MIC signals are then applied to the modulation circuit. MODULATION CIRCUITS (RF UNIT) -

48、MIC SIGNALS - The modulation circuits modulates the VCO oscillating signal using the modulation signals. The MIC signals from AF circuits are passed through the D/A converter (IC10, pins 21, 22) for level (deviation) adjustment. The level adjusted MIC signals are applied to the variable capacitor (D

49、61) in the VCO (Q76, D59D61), and modulate the VCO oscillating signal by changing the reactance of D61. The modulated VCO output are buffer- amplified by Q75 and Q74, then applied to the transmit amplifier as a transmit signal. - TONE SIGNALS - CTCSS/DTCS signals are output from CPU (LOGIC UNIT; IC8, pin 2) and passed through the LPF (R224, R227, C219), then applied to the LPF (as the AF mixeRF UNIT; IC3, pin 13) to be mixed with MIC signals. The mixed CTCSS/DTCS signals are applied to modulation circu