IC2820H_serv.pdf

S-14325XZ-C1 Mar. 2007 DUAL BAND FM TRANSCEVER This service manual describes the latest service information for the IC-2820H DUAL BAND FM TRANSCEVER at the time of publication. NEVER connect the transceiver to an AC outlet or to a DC power supply that uses more than 15 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 20 dBm (100 mW) to the antenna connector (J1). This could damage the transceivers front end. To upgrade quality, any electrical or mechanical parts and internal circuits are subject to change without notice or obligation. MODELVERSION IC-2820H USA-01 AUS-01 KOR-01 TPE-01 EXP-01 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 1110003491 S.IC TA31136FNG IC-2820H MAIN UNIT 5 pieces 8820001210 Screw 2438 screw IC-2820H Top cover 10 pieces Addresses are provided on the inside back 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 NOT 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 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 Modulation Analyzer or spectrum analyzer when using such test equipment. 8. READ the instructions of test equipment thoroughly before connecting equipment to the transceiver. REPAIR NOTES INTRODUCTIONCAUTION CONTENTS SECTION 1 SPECIFICATIONS SECTION 2 INSIDE VIEWS SECTION 3 DISASSEMBLY INSTRUCTIONS SECTION 4 CIRCUIT DESCRIPITON 4-1 RECEIVER CIRCUITS . 4-1 4-2 TRANSMITTER CIRCUITS . 4-4 4-3 FREQUENCY SYNTHESIZER . 4-6 4-4 POWER SUPPLY CIRCUITS . 4-8 4-5 PORT ALLOCATIONS . 4-9 SECTION 5 ADJUSTMENT PROCEDURES 5-1 PREPARATION . 5-1 5-2 FREQUENCY ADJUSTMENT . 5-2 5-3 TRANSMIT ADJUSTMENT . 5-3 5-4 RECEIVE ADJUSTMENT . 5-4 SECTION 6 PARTS LIST SECTION 7 MECHANICAL PARTS SECTION 8 BOARD LAYOUTS SECTION 9 BLOCK DIAGRAM SECTION 10 VOLTAGE DIAGRAM SECTION 11 HM-133 SECTION 12 UT-123 (Optional product) 1 - 1 SECTION 1 SPECIFICATIONS ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? M ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? M M 2 - 1 SECTION 2 INSIDE VIEWS D/A converter (IC8: M62364FP) Level converter (IC46: MAX3221IPWR) 1st IF Mixer for VHF bands (IC19: SPM5001) LO divider (79.150121.150 MHz) BOTTOM VIEW TOP VIEW IF IC (Right band) (IC18: TA31136FNG) IF IC (Left band RX) (IC15: TA31136FNG) Reference frequency oscillator (Left band) Reference frequency oscillator (Right band) VHF PA module (IC3: S-AV32) UHF PA module (IC2: S-AU82L) CPU (IC25: HD64F2506FC26) EEPROM (IC22: 24LC512) DTMF decoder (IC56: BU8872FS) AF power amplifier (IC38: LA4445) D/A converter (IC1: M62364FP) AF switch (IC30: CD4066BPWR) AF switch (IC31: CD4066BPWR) AF filter (IC48: LM2902PWR) D/A converter (IC54: M62364FP) Electric volume (IC33: SM6451B) Frequency synthesizer (Right band) Frequency synthesizer (Left band) LO filter (763.650953.640 MHz) 1st IF Mixer for UHF bands (IC20: SPM5001) 3 - 1 SECTION 3 DISASSEMBLY INSTRUCTION 1. Removing the top cover q Unscrew 10 screws, then remove the top cover. 3. Removing the MAIN UNIT q Unscrew 11 screws from the MAIN UNIT. 2. Removing the bottom cover q Unscrew 7 screws, then remove the bottom cover. 10 screws Top cover w Disconnect the speaker cable. Speaker cable Bottom cover 7 screws w Disconnect the cooling fan cable, and unsolder 6 points at the antenna connectors (grey colored). 6 unsoldering points Cooling fan cable MAIN UNIT e Remove the MAIN UNIT in the direction of the arrow. 4 - 1 SECTION 4 CIRCUIT DESCRIPTION 4-1 RECEIVER CIRCUITS RF CIRCUITS 118174 MHz The received signals from the antenna connector ANT-1 (J1) are passed through two LPFs (L101, 104, 108, C342, 346; L88, 92, 96, C318, 326, 330), then applied to the RF amplifi er (Q37) via TX/RX switch (D75). The amplifi ed signals are passed through the RX switch (RL2), attenuator (D68) and tuned BPF (D55, 66), before being applied to another RF amplifi er (Q33). The amplifi ed signals are applied to the 1st mixer (IC19) via the another tuned BPF (D41, 44) and RX switch (D38). While the diversity operation is activated, the received signals are also input from ANT-2 (J2). The received signals are passed through two LPFs (L103, 106, 109, C344, 348; L90, 93, 98, C319, 327, 348), antenna switch (D65, 72) and limitter (D64, 67), then applied to the RF amplifi er (Q39). The amplified signals are applied to the RX switch (RL2), and gone through the same process as the received signals from ANT-1 (J1). 174260 MHz The received signals from the antenna connector (J1) are passed through two RX switches (RL3 and D56) and the tuned BPF (D51), then applied to the RF amplifier (Q34). The amplified signals are passed through the BPF (D45), attenuator (R139, 144, 147) and RX switch (D36) before being applied to the 1st mixer (IC19). 260375 MHz The received signals from the antenna connector (J1) are passed through two RX switches (RL3 and D57) and the tuned BPF (D50), then applied to the RF amplifi er (Q35). The amplifi ed signals are passed through the BPF (D465), attenuator (R142, 143, 150) and RX switch (D37) before being applied to the 1st mixer (IC19). 375550 MHz The received signals from the antenna connector (J1) are passed through the LPF (L101, 104, 108, C342, 346) and HPF (L77, 80, C296, 297, 303, 308), then applied to the RF amplifier (Q28) via TX/RX switch (D53, 61, 62). The amplifi ed signals are passed through the RX switch (RL1), attenuator (D28) and tuned BPF (D19, 21, 24, 27), before being applied to another RF amplifi er (Q20). The amplifi ed signals are applied to the 1st mixer (IC19) via the another tuned BPF (D11, 13, 15, 17) and RX switch (D8). While the diversity operation is activated, the received signals are also input from antenna connector ANT-2 (J2). The received signals are passed through the LPF (L103, 106, 109, C344, 348), HPF (L95, 99, C329, 333, 338), antenna switch (D69, 73, 74) and limitter (D63, 66), then applied to the RF amplifi er (Q29). The amplified signals are applied to the RX switch (RL1), and gone through the same process as the received signals from ANT-1 (J1). RF AMP RX SW LPF HPF ATT RX SW ATT BPFATT RX SW HPF RF AMP ATT RF AMP BPF ATT RF AMP LPF ANT SW BPF RF AMP BPF RF AMP RX SW LPF RF AMP BPF RF AMP LPF BPF ATT RF AMP HPF BPF BPF RX SW BPF BPF RX SW BPF RF AMP RX SW RX SW RF AMP TX/RX SW RX SW HPF ATT RX SW ANTENNA ATT RX SW RX SW RX SW ANT SW BPF ANTENNA RF AMP D62 TX/RX SW D59 D77 D75 D61 D53 LIMIT D10, D32D8 D64,D67 D11 D58 RL1 D14, D76 Q29 D60 Q28 D38 D16 D70 ,D13, D65,D71,D72 D23, Q38 D28 D19, D55, Q37 D24, RL2 Q30 D17 D63,D66 D18, Q20 D30 Q32 D48,D49 D15, D12, LIMIT 375550 MHz D40, D78, LIMIT 375550 MHz D69,D73,D74 D44 D35 D26 118174 MHz D7 118174 MHz Left band Right band D41, D27 D68 Q39 D43 LIMIT D20, D54, Q33 8101000 MHz D37 D51 Q18 D50 D46 D45 Q35 D80 D22 D9 Q40 D36 Q23 Q34 174260 MHz 260375 MHz RL3 D57 D56 D79 Q19 D21, RF CIRCUITS 4 - 2 1ST IF CIRCUITS RX signals from the RF circuits are converted into the 38.85 MHz 1st IF signal by being mixed with LO signals from the left band VCO (Q111, D145147). The converted IF signal from the 1st mixer is passed through the IF fi lter (FI5) to be fi ltered. The fi ltered IF signal is applied to the 1st IF amplifi er (Q66) via the limiter (D88). The amplifi ed 1st IF signal is applied to the IF IC (IC15, pin 16) 2ND IF AND DEMODULATOR CIRCUITS (Fig. 2) IC15 is an IF IC which contains 2nd mixer, limiter amplifi er, noise amplifi er, quadrature detector and RSSI circuit, etc. in its package. The 1st IF signal from the 1st IF amplifi er (Q66) is converted into the 450 kHz 2nd IF signal by being mixed with tripled reference frequency signal (38.4 MHz) from the PLL IC (IC41) via the tripler (Q105). The converted 2nd IF signal is output from pin 3, and passed through the ceramic filter (FI1 for narrow mode, FI2 for wide mode) to remove sideband noise, then applied to the IF IC from pin 5 again. FM DEMODULATOR The fi ltered 2nd IF signal from pin 5 is amplifi ed at the limiter amplifier, and FM-demodulated at the quadrature detector circuit. The demodulated AF signals are output from pin 9 and routed to the AF circuits via two AF switches (IC11 and IC13). AM DEMODULATOR CIRCUITS In the AM mode, the 2nd IF signal from the FI2 is applied to the AM-demodulator circuit (Q55, Q57). The demodulated AF signals are routed to the AF circuits via two AF switches (IC11 and IC13). SQUELCH CIRCUITS NOISE SQUELCH A portion of FM-demodulated AF signals from the IF IC (IC15, pin 9) are level-adjusted by D/A converter (IC8), and passed throuhgh the noise fl tier (IC15 and some R and C) to be fi ltered noise components (30 kHz and above signals) in the AF signals. The fi ltered noise components aree detected in the IC15 and output from pin 13, then applied to the CPU (IC25, pin 100) as “L_SQL” signal. Then the CPU outputs “L_AF_MUTE” signal from pin 82 to the speaker mute switch (Q102), according to the “L_SQL” signal level. Thus the AF line is connected to the GND to turn the AF output OFF. CTCSS/DTCS CTCSS/DTCS signals in the demodulated AF signals from the AF switch (IC13) are passed through the tone fi lter (Q41) . The fi ltered CTCSS/DTCS signals are applied to the CPU IC25, pin 70) as “L_DTCSIN” signal. The CPU (IC25) com- pares the applied signal and the set CTCSS/DTCS, then out- puts control signal as same as “NOISE SQUELCH.” DTMF DTMF signals in the demodulated AF signals from the AF switch (IC13) are passed through two AF switches (IC57 and IC58), then applied to the DTMF decoder (IC56) to be decoded. AF CIRCUITS The AM/FM-demodulated AF signals from the AF switch (IC11) are passed through the AF filter (Q47). The filtered AF signals are applied to the electric volume (IC33) to be adjusted its level. The level-adjusted AF signals are applied to the dual AF power amplifiier (IC38) to obtain AF output power level, then applied to the internal (CHASSIS; SP1) or an external speaker via external speaker jack (J7). If an external