IC-T3H_serv.pdf

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1、S-13804MZ-C1 2001 Icom Inc.1-1-32, Kamiminami, Hirano-ku, Osaka 547-0003, Japan Count on us! iC-t3h iC-t3h VHF TRANSCEIVER Communication Equipment Himmelgeister Str. 100, D-40225 Dsseldorf, Germany Phone: 0211 346047Fax : 0211 333639 URL: Unit 9, Sea St., Herne Bay, Kent, CT6 8LD, U.K. Phone: 01227

2、741741 Fax : 01227 741742 URL: http:/www.icomuk.co.uk Zac de la Plaine, Rue Brindejonc des Moulinais BP 5804, 31505 Toulouse Cedex, France Phone: 561 36 03 03Fax : 561 36 03 00 URL: http:/www.icom- Crta. de Gracia a Manresa Km. 14,750 08190 Sant Cugat del Valles Barcelona, SPAIN Phone: (93) 590 26 7

3、0 Fax : (93) 589 04 46 URL: 2380 116th Avenue N.E., Bellevue, WA 98004, U.S.A. Phone: (425) 454-8155Fax : (425) 454-1509 URL: Phone: (425) 454-7619 Glenwood Centre #150-6165 Highway 17 Delta, B.C., V4K 5B8, Canada Phone: (604) 952-4266Fax : (604) 952-0090 URL: A.B.N. 88 006 092 575 290-294 Albert St

4、reet, Brunswick, Victoria, 3056, Australia Phone: 03 9387 0666Fax : 03 9387 0022 URL: .au 146A Harris Road, East Tamaki, Auckland, New Zealand Phone: 09 274 4062Fax : 09 274 4708 URL: http:/www.icom.co.nz 6F No. 68, Sec. 1 Cheng-Teh Road, Taipei, Taiwan, R.O.C. Phone: (02) 2559 1899Fax : (02) 2559 1

5、874 1-1-32, Kamiminami, Hirano-ku, Osaka 547-0003, Japan Phone : 06 6793 5302 Fax: 06 6793 0013 URL: http:/www.icom.co.jp/world/index.html INTRODUCTION DANGER ORDERING PARTS REPAIR NOTES This service manual describes the latest service information for the IC-T3H at the time of publication. NEVER con

6、nect the transceiver to an AC outlet or to a DC power supply that uses more than 10.3 V. Such a connection could cause a fire hazard and/or electric shock. DO NOT expose the transceiver to rain, snow or any liquids. DO NOT reverse the polarities of the power supply when con- necting the transceiver.

7、 DO NOT apply an RF signal of more than 20 dBm (100mW) to the antenna connector. This could damage the transceiv- ers front 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

8、name 4. Quantity required 0910053802PCB B-5649BIC-T3HMAIN UNIT1 pieces 8810009560 ScrewBT M2 x 6 ZKIC-T3HChassis10 pieces 8810009510 ScrewBT 2 x 4 NIIC-T3HChassis10 pieces Addresses are provided on the inside back cover for your convenience. 1. Make sure a problem is internal before disassembling th

9、e 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 turning tool MUST be used for all adjustments. 5. D

10、O 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 40 dB to 50 dB attenuator between the transceiver and a deviation meter or spectrum analyzer when using such test equipment. 8. READ the i

11、nstructions of test equipment thoroughly before connecting equipment to the transceiver. To upgrade quality, all electrical or mechanical parts and internal circuits are subject to change without notice or oblig- ation. TABLE OF CONTENTS SECTION 1 SPECIFICATIONS SECTION 2INSIDE VIEWS SECTION3 DISASS

12、EMBLY INSTRUCTIONS SECTION 4CIRCUIT DESCRIPTION 4 - 1 RECEIVER CIRCUITS . 4 - 1 4 - 2 TRANSMITTER CIRCUITS . 4 - 2 4 - 3 PLL CIRCUIT. 4 - 3 4 - 4 OTHER CIRCUITS. 4 - 3 4 - 5 POWER SUPPLY CIRCUITS . 4 - 3 4 - 6 CPU PORT ALLOCATIONS . 4 - 4 SECTION 5ADJUSTMENT PROCEDURES 5 - 1 PREPARATION. 5 - 1 5 - 2

13、 PLL ADJUSTMENT. 5 - 2 SECTION 6PARTS LIST SECTION 7 MECHANICAL PARTS AND DISASSEMBLY SECTION 8SEMI-CONDUCTOR INFORMATION SECTION 9 BOARD LAYOUTS 9 - 1 MAIN UNIT. 9 - 1 SECTION 10 BC-146 OPTIONAL DESKTOP CHARGER INFORMATION 10 - 1 PARTS LIST. 10 - 1 10 - 2 DISASSEMBLY INFORMATION. 10 - 1 10 - 3 VOLT

14、AGE DIAGRAM. 10 - 2 10 - 4 BOARD LAYOUT. 10 - 2 SECTION 11 BLOCK DIAGRAM SECTION 12 VOLTAGE DIAGRAM SECTION 1SPECIFICATIONS 1 - 1 GENERAL Frequency coverage: TX/RX 144.000146.000 MHz Type of emission: F2D/ F3E Frequency stability: 10 ppm (10C to +60C; +14F to +140F) Tuning steps: 5, 10, 12.5, 15, 20

15、, 25, 30 or 50 kHz Antnna connector: BNC (50 ) Power supply requirement: 7.2 V DC (Operable voltage range: 6.0 to 10.3 V) (negative ground) Number of memory channel: 100 channels Call channel: 1 channel Scanning mode: Program, Memory, Skip, Priority or Tone Current drain (approx.): Transmitat High (

16、5.5 W)2.0 A at Low (0.5 W)0.7 A ReceiveMax. audio 250 mA stand-by70 mA power saved20 mA Usable temperature range: 10C to +60C; +14F to +140F Dimensions (projections not included): 54(W) 132(H) 35(D) mm; 2 18(W) 5 316(H) 1 38(D) in. Weight (with ant., BP-222): 350 g; 12.3 oz. TRANSMITTER RF output po

17、wer (at 7.2 V DC): 5.5 W / 0.5 W (High / Low) (with supplied battery pack) Modulation system: Variable reactance frequency modulation Maximum frequency deviation: 5.0 kHz Spurious emissions: Less than 60 dB Ext. microphone connector: 3-conductor 2.5(d) mm (110”)/2.2 k RECEIVER Receive system: Double

18、 conversion superheterodyne system Intermediate frequencies: 1st21.7 MHz 2nd450 kHz Sensitivity: 0.16 V at 12 dB SINAD (typical) Squelch sensitivity: 0.1 V at threshold (typical) Adjacent channel selectivity: 65 dB (typical) Spurious response rejection: 75 dB (typical) Intermodulation rejection rati

19、o: 65 dB (typical) Audio output power (at 7.2 V DC): More than 300 mW at 10% distortion with an 8 load Ext. speaker connector: 3-conductor 3.5(d) mm (18”)/8 All stated specifications are subject to change without notice or obligation. 2 - 1 SECTION 2INSIDE VIEWS Power amplifier (Q1: 2SK3476) Antenna

20、 swtching circuit (D2, D8: MA77) Antenna swtching circuit (D1: MA77) TOP VIEWBOTTOM VIEW RF amplifier (Q12: 3SK274) VCO circuit 1st mixer (Q13: 3SK274) TX/RX switch (D3, D4: MA77) APC IC3A: NJM12902V Q37: DTA144EU FM IF IC (IC2: TA31136FN) CPU (IC8: HD6473877H) EEPROM (IC7: BR24C16FV) D/A converter

21、(IC10: M62363FP) PLL reference oscillator (X1: CR-659 21.25 MHz) Crystal filter FI1, Fl3:FL-298 21.700 MHz PLL IC (IC1: LV2105V) IF amplifier (Q14: 2SC4406) ( ) ( ) 3 - 1 SECTION 3DISASSEMBLY INSTRUCTIONS 3-1 DISASSEMBLY INSTRUCTION REMOVING THE CHASSIS PANEL 1 Unscrew 1 nut A, and remove 1 knob B.

22、2 Unscrew 2 screws C. 3 Take off the chassis in the direction of the arrow. 4 Unplug J6 to separate front panel and chassis. REMOVING THE MAIN UNIT 1 2 Unsolder 3 points D, and unscrew 1 nut E. 3 Unscrew 2 screws F, 2 screws H, and 6 screws G (silver, 2 mm) to separate the chassis and the MAIN unit.

23、 (black, 2 mm) x 2 Front panel Chassis J6 (Speaker connector) B C A H (black, 2 mm) x 2 (silver, 2 mm) x 6 Shield cover Guide holes MAIN unit Chassis D D G D E G G F (black, 2 mm) x 2 Take off the MAIN unit in the direction of the arrow. 3 - 2 3-2 OPTIONAL UNIT INSTALLATIONS 1 Remove the option cove

24、r. 2 Remove the bottom protective paper of spoge. 3 Connect the UT-108 optional unit to J5. 4 Replace the option cover to the chassis-hole. SPONGE Parts name : 1556 sponge Order No.: 8930013545 Option cover Option unit J5 SECTION 4CIRCUIT DESCRIPTION 4 - 1 4-1RECEIVER CIRCUITS 4-1-1ANTENNA SWITCHING

25、 CIRCUIT Received signals passed through the low-pass filter (L1, L2, C1C5). The filtered signals are applied to the 1/4 type antenna switching circuit (D1, D2, D8, L15, C76). The antenna swtiching circuit functions as a low-pass filter while transmitting. However, its impedance becomes very high wh

26、ile D2 and D8 are turn ON. Thus transmit signals are blocked from entering the receiver circuits. The antenna switching circuit employs a 1/4 type diode swtiching sys- tem. The passed signals are then applied to the RF amplifi- er circuit. 4-1-2RF CIRCUIT The RF circuit amplifies signals within the

27、range of frequen- cy coverage and filters out-of-band signals. The signals from the antenna switching circuit are applied to the limitter (D50), and are then passed through the band- pass filter (D9, L16, C80). The filtered signals are amplified at the RF amplifier (Q12), then applied to the 1st mix

28、er cir- cuit after out-of-band signals are suppressed at the band- pass filter (D11, D12, L19, C91C97). D9, D11, D12 employ varactor diodes that track the band- pass filters and are controlled by the T1T3 signals from the D/A convertor (IC10, pins 2, 3, 10). These diodes tune the center frequency of

29、 an RF passband for wide bandwidth receiving and good image response rejection. 4-1-31ST MIXER AND 1ST IF CIRCUITS The 1st mixer circuit converts the received signal to a fixed frequency of the 1st IF signal with a PLL output frequency. By changing the PLL frequency, only the desired frequency will

30、pass through two crystal filters at the next stage of the 1st mixer. The signals from the RF circuit are mixed at the 1st mixer (Q13) with a 1st LO signal coming from the VCO circuit to produce a 21.70 MHz 1st IF signal. The 1st IF signal is applied to two crystal filters (FI1 and FI3) to suppress o

31、ut-of-band signals. The filtered 1st IF signal is applied to the IF amplifier (Q14), then applied to the 2nd mixer circuit (IC1, pin 16). 4-1-42ND IF AND DEMODULATOR CIRCUITS The 2nd mixer circuit converts the 1st IF signal to a 2nd IF signal. A double conversion superheterodyne system (which conver

32、ts receive signal twice) improves the image rejection ratio and obtain stable receiver gain. The 1st IF signal from the IF amplifier is applied to the 2nd mixer section of the FM IF IC (IC2, pin 16), and is mixed with the 2nd LO signal to be converted to a 450 kHz 2nd IF sig- nal. The FM IF IC conta

33、ins the 2nd mixer, limiter amplifier, quad- rature detector and active filter circuits. A 21.25 MHz 2nd LO signal is produced at the PLL circuit. The 2nd IF signal from the 2nd mixer (IC2, pin 3) passes through a ceramic filter (FI2) to remove unwanted hetero- dyned frequencies. It is then amplified

34、 at the limiter amplifi- er (IC2, pin 5) and applied to the quadrature detector (IC2, pins 10, 11) to demodulate the 2nd IF signal into AF signals. 4-1-5AF CIRCUIT The AF amplifier circuit amplifies the demodulated AF sig- nals to drive a speaker. AF signals from the FM IF IC (IC2, pin 9) are applie

35、d to the analog swtich (IC4, pin 1) via the AF filter circuit (IC3b, pins 6, 7). The output signals from pin 2, 3 are passed through the low-pass filter (IC3d, pins 13, 14), and are then applied to the analog swtich (IC4, pin 9, 10) again. The signals from the IC4, pin 11 are applied to the AF power

36、 amplifier (IC5, pin 4) after passing through the D/A convertor (IC10, pins 12, 11). Mixer 16 Limiter amp. 2nd IF filter 450 kHz PLL IC IC1 X1 21.25 MHz IC2 TA31136F 12 1st IF from the IF amplifier (Q14) SD signal to the CPU pin 98 11109 8753 AF signal DET R5 X3 R86 C122C121 R88R87 R83 SQLIN signal

37、from the D/A convertor (IC10, pin 23) R82 C112C113 C116 2 161 Active filter FI2 Noise detector FM detector 13 NOIS signal to the CPU pin 19 RSSI Noise comp. R84 LPF 2ND IF AND DEMODULATOR CIRCUITS 4 - 2 The AF signals are applied to the AF power amplifier circuit (IC5, pin 4) to obtain the specified

38、 audio level. The amplified AF signals, output from pin 10, are applied to the internal speaker (SP1) via the speaker jack (CHASSIS unit; J3) when no plug is connected to the jack. 4-1-6SQUELCH CIRCUIT A squelch circuit cuts out AF signals when no RF signals are received. By detecting noise componen

39、ts in the AF signals, the squelch switches the analog swtich. A portion of the AF signals from the FM IF IC (IC2, pin 9) are applied to the active filter section (IC2, pin 8) where noise components are amplified and detected with an internal noise detector. The trigger circuit converts the detected

40、signals to a HIGH or LOW signal and applies this (from pin 13) to the CPU (IC8, pin 19) as the NOIS signal. When the CPU receives a HIGH level NOIS signal, the CPU controls the RMUT line to cut the AF signals at the analog swtich IC (IC4). At the same time, the AFON line controls the AF regulator ci

41、rcuit (Q15, Q16) to cut out the VCC power source for the AF power amplifier (IC5). 4-2TRANSMITTER CIRCUITS 4-2-1MICROPHONE AMPLIFIER CIRCUIT The microphone amplifier circuit amplifies audio signals with +6 dB/octave pre-emphasis from the microphone to a level needed for the modulation circuit. The A

42、F signals from the microphone are applied to the microphone amplifier circuit (IC3c, pin 10). The amplified AF signals are passed through the low-pass filter circuit (IC3d, pins 13, 14) via the analog swtich (IC4, pins 4, 3). The fil- tered AF signals are applied to the modulator circuit after passi

43、ng through the analog swtich (IC4, pins 8, 9). 4-2-2MODULATION CIRCUIT The modulation circuit modulates the VCO oscillating signal (RF signal) using the microphone audio signals. The audio signals (SHIFT) change the reactance of D37 to modulate an oscillated signal at the VCO (Q50, D38). The oscilla

44、ted signal is amplified at the LO (Q6) and buffer (Q4) amplifiers, then applied to the TX/RX switch circuit (D3, D4). 4-2-3DRIVE/POWER AMPLIFIER CIRCUITS The signal from the VCO circuit passes through the TX/RX swtiching circuit (D3) and is amplified at the pre-drive (Q3), drive (Q2) and power (Q1)

45、amplifiers to obtain 5.5 W of RF power (at 7.2 V DC/typical). The amplified signal passes through the low-pass filter (L4, C278, C287), and then applied to the antenna swtiching circuit (D1). The signal is applied to the antenna connector (J1) after being passed through the low-pass filter (L1, L2, C1C5). The bias current of the drive (Q2) and power (Q1) amplifiers is controlled by the APC circuit to