SERVICE MANUAL UHF FM TRANSCEIVERS 1-1-32, Kamiminami, Hirano-ku, Osaka, 547-0003, Japan S-13717IZ-C1 © 2001 Icom Inc.
INTRODUCTION This service manual describes the latest service information for the IC-F21/IC-F21S at the time of publication. To upgrade quality, all electrical or mechanical parts and internal circuits are subject to change without notice or obligation. DANGER NEVER connect the transceiver to an AC outlet or to a DC power supply that uses more than 16 V. Such a connection could cause a fire hazard and/or electric shock. DO NOT expose the transceiver to rain, snow or any liquids.
TABLE OF CONTENTS SECTION 1 SPECIFICATIONS SECTION 2 INSIDE VIEWS SECTION 3 DISASSEMBLY INSTRUCTIONS SECTION 4 CIRCUIT DESCRIPTION SECTION 4-1 RECEIVER CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-1 4-2 TRANSMITTER CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-2 4-3 PLL CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SECTION 1 SPECIFICATIONS ‘ GENERAL • Frequency coverage : 440.000–470.000 MHz • Type of emission : 16K0F3E (at 25 kHz), 8K50F3E (at 12.5 kHz) • Number of channels : 2 ch (IC-F21S), 16 ch (IC-F21) • Power supply requirement : 7.2 V DC (negative ground) • Current drain (approx.) : Transmit at High (4.0 W) at Low2 (2.0 W) at Low1 (1.0 W) rated audio stand-by Receive 1.6 A 1.2 A 0.8 A 250 mA 70 mA • Frequency stability : ±0.
SECTION 2 INSIDE VIEWS • MAIN UNIT TOP VIEW BOTTOM VIEW Antenna switching circuit D1: 1SV307 D9, D10: MA77 ( ) RF amplifier (Q15: 3SK293) Power amplifier (Q1: 2SK2974) APC (IC2: TA75S01F) Pre-drive (Q2 : 2SK2973) AF amplifier (IC4: TA7368F) Analog switch (IC6: BU4066BCFV) YGR amplifier 2SC3585 (Q3: Q4: 2SC5107 ) D/A converter (IC9: M62363FP) TX/RX switch (D3, D4: MA77) Crystal filter (FI1: FL-313) FM IF IC (IC3: TA31136FN) VCO circuit PLL reference oscillator (X1: CR-671A 15.
SECTION 3 DISASSEMBLY INSTRUCTIONS • REMOVING THE CHASSIS ¡ Unscrew 1 nut, A, and remove 2 knobs, B, C. ™ Unscrew 2 screws, D. £ Unscrew 2 screws, H, to separate the Jack panel and the Front panel. ¢ Take off the chassis in the direction of the arrow. ∞ Unplug J6 to separate the front panel and the chassis. D (Black, 2mm) x 2 Chassis C B J6 (Speaker connector) A Jack panel Front panel H (Black, 2mm) x 2 • REMOVING THE MAIN UNIT ¡ ™ £ ¢ Remove the sealing rubber.
SECTION 4 CIRCUIT DESCRIPTION The signals from the RF circuit are mixed at the 1st mixer (Q16) with a 1st LO signal (393.65–423.65 MHz) coming from the VCO circuit to produce a 46.35 MHz 1st IF signal. 4-1 RECEIVER CIRCUITS 4-1-1 ANTENNA SWITCHING CIRCUIT The antenna switching circuit functions as a low-pass filter while receiving. However, its impedance becomes very high while D9 and D10 are turned ON. Thus transmit signals are blocked from entering the receiver circuits.
The applied AF signals are amplified at the AF power amplifier circuit (IC4, pin 4) to obtain the specified audio level. The amplified AF signals output from pin 10 as “AFOUT”signal are applied to the internal speaker (SP1) as the “SP” signal via the [SP] jack when no plug is connected to the jack. 4-2-2 MODULATION CIRCUIT The modulation circuit modulates the VCO oscillating signal (RF signal) using the microphone audio signal.
The pulse-type signal is converted into DC voltage (lock voltage) at the loop filter (R40–R42, C74–C77), and then applied to varactor diodes (D5) of the RX-VCO to stabilize the oscillated frequency. The lock voltage is also used for the receiver circuit for the bandpass filter center frequency. The lock voltage from the loop filter is amplified at the buffer amplifier (Q13) and then applied to the CPU (IC7, pin 60). The signal is analyzed at the CPU, and then applied to the D/A convertor (IC9).
4-5 PORT ALLOCATIONS 4-4 POWER SUPPLY CIRCUITS 4-5-1 CPU (IC7) VOLTAGE LINE LINE HV VCC Pin number Port name The voltage from the attached battery pack. 7 RES The same voltage as the HV line (battery voltage) which is controlled by the power swtich ([VOL] control). 13 14 19 20 SENC0 SENC1 SENC2 SENC3 Outputs single tone encode signal. 23 24 25 CENC0 CENC1 CENC2 Outputs CTCSS/DTCS data signal. DESCRIPTION Description Input port for RESET signal.
CPU (IC7)–continued Pin number Port name Description 61 BDET Input port for the battery’s type detection. 62 BATV Input port for battely voltage detection. 4-5-2 OUTPUT EXPANDER IC (IC15) Pin number Port name Description 4 CSFT Outputs clock shift control signal for CPU. 5 RMUT Outputs RX mute control signal. 6 MMUT Outputs TX mute control signal. 7 DUSE Outputs low-pass filter cut-off frequency control signal when DTCS is activated. 11 T5C Outputs T5 regulator control signal.
SECTION 5 ADJUSTMENT PROCEDURES 5-1 PREPARATION When you adjust the contents on page 5-5 or 5-6, SOFTWARE ADJUSTMENT, the optional CS-F21 ADJ ADJUSTMENT SOFTWARE (Rev. 1.0 or later), OPC-478 CLONING CABLE and a JIG CABLE (see illustration at page 5-2) are required. ■ REQUIRED TEST EQUIPMENT EQUIPMENT GRADE AND RANGE DC power supply Output voltage Current capacity : 7.
Screen display exampe CS-F21 ADJ Rev.1.0 File Option COM 1: OPEN 2 Connect Reload (F5) Disp para 1 4 5 6 7 8 9 10 11 12 13 [A / D] VIN TEMPS LVIN SD REMOT BDET : : : : : : 197 190 98 0 14 255 CH No. Power (Hi) Power (L2) Power (L1) DTCS BAL MOD W MOD N SQL BPF ALL BPF T1 BPF T2 BPF T3 BPF T4 TXF : : : : : : C5h BEh 62h 00h 0Eh FFh : : : : : : [D / A] BPF T1 : BPF T2 : BPF T3 : T4/POW : REF : DTCS BL. : Dev : SQL Lev : 7.73 V 32.23 ’C 1.92 V 0.00 V 0.27 V 5.00 V : 01 (RX Freq = 216.
Connection Standard signal generator to the antenna connector 0.1 V to 32 mV (—127 dBm to —17 dBm) to [MIC] Audio generator CAUTION: DO NOT transmit while an SSG is connected to the antenna connector. to an RS-232C port Personal computer OPC-478 FM deviation meter Attenuator 40 dB or 50 dB RF power meter 0.1—10 W/50 ‰ DB9 female plug (incl.
5-2 PLL ADJUSTMENT MEASUREMENT ADJUSTMENT VALUE UNIT PLL LOCK VOLTAGE ADJUSTMENT ADJUSTMENT CONDITIONS 1 • Operating frequency: 440.000 MHz • Receiving LOCATION UNIT ADJUST MAIN Connect a digital multi meter to check point LV. 2 • Transmitting 1.3 V MAIN C54 1.3 V C68 3 • Operating frequency: 470.000 MHz • Receiving 2.8–4.3 V Verify 4 • Transmitting 2.8–4.
5-3 SOFTWARE ADJUSTMENT Select an operation using [↑] / [↓] keys, then set specified value using [←] / [→] keys on the connected computer keyboard. ADJUSTMENT ADJUSTMENT CONDITION MEASUREMENT UNIT LOCATION VALUE REFERENCE FREQUENCY [TXF] 1 • Operating frequency: Top Loosely couple a frequnecy 470.000 MHz panel counter to the antenna connec• High/Low switch : Low tor. • Connect the RF power meter or 50 Ω dummy load to the antenna connector.
SOFTWARE ADJUSTMENT – continued Select an operation using [↑] / [↓] keys, then set specified value using [←] / [→] keys on the connected computer keyboard. ADJUSTMENT ADJUSTMENT CONDITION MEASUREMENT UNIT LOCATION VALUE 1 • Operating frequency: RX Top Connect a SINAD meter with an Minimum distortion level 440.000 MHz SENSITIVITY panel 8 Ω load to the [SP] jack. • Channel spacing :Narrow [BPF T1]–[BPF T4] • Connect a standard signal generator to the antenna connector and set as: Frequency : 440.
SECTION 6 PARTS LIST [SW-A UNIT] ([F21] only) REF NO. ORDER NO. [MAIN UNIT] REF NO. DESCRIPTION Q1 1590003020 S.TRANSISTOR XP4216-(TX) R1 R2 R3 7210003060 VARIABLE 7030003380 S.RESISTOR 7030003410 S.RESISTOR TP76N00N-15F-10KA-2251 ERJ3GEYJ 331 V (330 Ω) ERJ3GEYJ 561 V (560 Ω) F1 5210000710 S.FUSE KAB 2402 322 NA29 DS1 5040002070 S.LED LNJ107W5PRW S1 2250000430 ENCODER TP70QF4161-16F-2458 EP1 0910053673 PCB B 5603C [SW-B UNIT] ([F21S] only) REF NO. ORDER NO.
[MAIN UNIT] REF NO. [MAIN UNIT] ORDER NO. REF NO. DESCRIPTION L13 L14 L15 L16 L17 L18 L19 L20 L21 L22 L23 L24 L25 L26 L27 L28 L29 L30 6200009360 6200002860 6200002800 6200009360 6200002860 6200005680 6200008240 6200008240 6200007670 6200007670 6200007670 6200007670 6200005720 6200001980 6200002850 6200002840 6200009210 6200009760 S.COIL S.COIL S.COIL S.COIL S.COIL S.COIL S.COIL S.COIL S.COIL S.COIL S.COIL S.COIL S.COIL S.COIL S.COIL S.COIL S.COIL S.COIL 0.45-1.
[MAIN UNIT] REF NO. R152 R153 R154 R155 R156 R157 R158 R159 R160 R161 R163 R164 R165 R166 R167 R168 R169 R170 R171 R172 R173 R174 R175 R176 R177 R178 R179 R180 R181 R182 R184 R185 R186 R187 R188 R189 R190 R191 R192 R193 R194 R195 R196 R197 R198 R199 R200 R201 R202 R203 R204 R205 R206 R207 R208 R209 R210 R211 R212 R213 R214 R215 R216 R217 R218 R219 R220 R221 R222 R223 R224 R225 R226 R227 R228 R229 R232 R233 R234 R238 R239 R240 [MAIN UNIT] ORDER NO.
[MAIN UNIT] REF NO. C86 C87 C88 C89 C90 C91 C92 C93 C94 C96 C97 C98 C99 C100 C102 C103 C104 C105 C106 C107 C108 C109 C110 C111 C112 C113 C114 C115 C116 C117 C118 C119 C120 C121 C122 C123 C124 C125 C126 C127 C128 C129 C130 C132 C133 C134 C136 C137 C138 C139 C140 C142 C143 C144 C145 C146 C147 C148 C149 C150 C151 C152 C153 C154 C155 C156 C157 C158 C159 C160 C161 C162 C163 C164 C165 C166 C167 C168 C169 C170 C171 C172 [MAIN UNIT] ORDER NO.
[MAIN UNIT] REF NO. ORDER NO. DESCRIPTION C261 4030007090 S.CERAMIC C1608 CH 1H 470J-T-A J1 J2 J3 J4 J5 6910013720 6910013730 6510021900 6450001680 6450001690 IMSA-9230B-04Z120-T IMSA-9230B-07Z120-T BM02B-ASRS-TF HSJ1122-010010 HSJ1456-01-220 MC1 7700002160 MICROPHON KUC3523-040245 S1 S2 S3 2230001060 S.SWITCH 2230001060 S.SWITCH 2230001060 S.SWITCH EVQ-PUL 02K EVQ-PUL 02K EVQ-PUL 02K W2 W4 W8 W12 W13 W14 7030003860 7030003860 7030003860 7030003860 7030003860 7030003860 S.JUMPER S.JUMPER S.
SECTION 7 MECHANICAL PARTS AND DISASSEMBLY [CHASSIS PARTS] REF. NO. ODER NO.
MP21 (C) MP32 (C) MP27 (C) MP14 (C) MP13 (C) MP8 (C) MP29 (C) MP39 (C) MP29 (C) MP12 (C) MP9 (C) MP35 (C)([F21S] only) MP18 (C) MP19 (C) MP6 (M) MP26 (C) MP29 (C) MP7(M) MP33 (C) MP4 (C) MP6 (C) MP22 (C) IC-F21S SP1 (C) MP29 (C) MP29 (C) MP28 (C) MP15 (C) MP10 (C) MAIN unit MP1 (M) MP2 (M) MP29 (C) MP30 (C) MP11 (C) MP29 (C) MP34 (C) MP20 (C) MP1 (C) MP7 (C) UNIT abbreviation (C): CHASSIS PARTS, (M): MAIN UNIT 7-2
SECTION 8 SEMI-CONDUCTOR INFORMATION • TRANSISTOR AND FET’S 2SA1577 Q (Symbol: HQ) 2SC3585 R44 (Symbol: R44) 2SB1132 R (Symbol: BARB) 2SC4116 GR (Symbol: LG) 2SC4215 O (Symbol: QO) C B B C B C E E B B C 2SK880 Y (Symbol: XY) 2SK1829 (Symbol: K1) 2SK2973 (Symbol: K1) S E E 2SK2974 (Symbol: K2974) 3SK272 (Symbol: K) CE B G C E C E B 2SC5107 O (Symbol: MFO) B C E E 2SC5085 Y (Symbol: MCY) B G S D C 3SK293 (Symbol: UF) DTA144 EU (Symbol: 16) E S D DTC144 EU (Symbol: 2
SECTION 9 BOARD LAYOUTS 9-1 MAIN UNIT EP2 L14 C160 C236 R208 R209 C234 R139 R206 IC5 R117 C233 L6 R11 C34 L30 L8 C18 C20 C158 R2 Q1 R6 R10 R238 C8 C17 L3 R5 R9 R7 C9 C24 C23 R8 C26 C27 C50 C163 R56 R55 D2 C213 J3 Q14 C15 J5 J4 C237 C207 2 GND 1 SP MC1 J3 to the speaker 9-1 4 CBI3 CBI2 CBI1 1 CBI0 C157 C164 IC10 C259 C206 S1 C93 R128 S3 R137 C184 Q4 C36 R17 C255 D3 R102 C70 R153 Q25 J1 to the SW-A unit C159 C156 R169 Q24 R170 C209 Q23 C
R157 C200 R160 C198 D21 R47 C72 C82 C168 R173 R175 C240 R49 R48 R52 Q31 Q26 C211 R172 9-2 C81 D20 IC1 R37 C169 D17 R152 IC11 R161 L18 R39 R46 R232 C212 Q27 R171 R174 IC8 C199 R219 C247 R241 C248 R44 C251 C78 R40 R211 R43 R27 C83 C80 R35 C71 R240 R45 R41 C73 Q13 C92 C89 R38 R105 C75 Q19 C47 C216 C90 R36 R33 Q9 Q8 R106 R202 R53 C76 C77 D22 C134 Q20 R107 C171 C239 C62 C261 IC4 R57 Q32 R213 EP4 EP5 C3 C91 C61 C96 C165 C59 C56 C132
9-2 SW-A AND SW-B UNITS DS1 Q1 F1 B5603C • TOP VIEW SW-A UNIT Q1 F1 DS1 SW-B UNIT 9-3
R3 R2 • BOTTOM VIEW SW-A UNIT S1 R1 CBI0 VOLOUT VOLIN VCC RLED TLED GND 1 1 4 7 W2 R1 B5604C J2 to the MAIN unit J2 CBI0 VOLOUT VOLIN VCC RLED TLED GND W1 R3 S1 R2 SW-B UNIT J2 to the MAIN unit J2 CBI0 CBI1 CBI2 CBI3 J1 to the MAIN unit J1 1 9-4 7
SECTION 10 BC-146 OPTIONAL DESKTOP CHARGER INFORMATION 10-1 PARTS LIST 10-2 DISASSEMBLY INFORMATION [CHARGE UNIT] REF. NO. ODER NO. DESCRIPTION QTY. R1 R2 7010007550 RESISTOR 7010007100 RESISTOR ERG3SJ680H PSD1/4V 1 kΩ 1 1 J1 6510021470 CONNECTOR HEC0470-01-230 1 DS1 5040001390 LED TLG124A 1 EP1 0910053820 PCB B 5650 1 MP1 MP2 8930051340 2338 TERMINAL 8930051340 2338 TERMINAL MP4 A MP5 A 1 1 MP1 A [CHASSIS UNIT] REF. NO. ODER NO.
10-3 VOLTAGE DIAGRAM C : 13.8V N : 13.8V C : 7.2V N : 13.8V MP1 R1 68 R2 1k J1 HEC0470-01-230 DS1 TLG124A C : 9.2V N : 13.
BLOCK DIAGRAM S5V Q13 2SK880 LVIN Q8 DTC144EU Q9 XP1214 RIPPLE FIL VCO SW ANT 440–470MHz Q10 2SC5085 D5 HVU350 BUFF IC1 MB15A02PFV1 15.3MHz LOOP FIL PLST SO SCK UNLK x3 Q4 2SC5107 TX / RX SW BUFF Q3 2SC3585 Q2 2SK2973 PRE DRIVE YGR AMP YGR AMP PWR AMP PWR DET D1 1SV307 D9,D10 MA77 ANT SW Q14 DTA144EU LPF Q33 3SK1829 1stLO 393.65–423.65 MHz BUFF RSSI IC3 TA31136FN Q17 2SC4215 IF IC 46.
SECTION 12 VOLTAGE DIAGRAM 12-1 MAIN UNIT VCC T5V VCC T5V S5V +5V S5V +5V 4.9 V R47 47 R50 56 D21 MA2S111 C80 47 P C83 100 P R244 22 LVIN R220 2.2 k R45 10 k R46 1.2 k C54 6P C58 10 C59 47 P R43 47 k D5 HVU350B PLST SO SCK UNLK OSCIN R OSCOUT P VP FOUT VCC NC FC DO LE GND DATA LD CLOCK FIN LOCK 4.5 V UNLOCK 0.5 V 15.3 MHz 0.75 V P-P 4.8 V D20 MA2S111 C86 0.001 R53 47 C87 47 P C88 0.1 EP7 C153 0.01 CBI0 CBI1 CBI2 CBI3 R97 680 k 0V 3.
VCC T5V VCO5V EP2 C48 0.001 VCC Q10 2SC5085 Y R27 10 k Q16 3SK272 0V 1.0 V R86 270 C128 0.001 C125 R79 10 P 470 D15 L24 10 nH R76 4.7 k L25 33 nH R82 47 k R80 12 R81 470 C120 8P C127 47 P R75 10 k T4 C119 0.5 P R74 220 k C122 5P C121 47 P C118 47 P R69 47 C113 8P C115 0.3 P L23 10 nH R70 220 k C116 6P R73 10 k 0V 4.6 V C112 0.001 C117 8P IC6 BU4066BCFV R125 1M C178 0.01 R119 150 k R121 0.8 k C177 2.2 R229 1.8 k C107 0.001 R64 100 k R228 470 k R120 39 k C175 0.
SECTION 12 VOLTAGE DIAGRAM 12-1 MAIN UNIT R98 47 k R99 1.2 k J2 CBI0 16 15 14 13 12 11 10 9 C144 0.001 C142 0.001 C186 0.0056 C187 0.022 10 9 Q22 UN911H C188 10 C189 470 P MIC R139 100 k R142 100 k C190 0.1 C185 0.1 MIC IC5C NJM13403V 8 C183 0.1 2.1 V C184 180 P R138 470 R137 180 k 5 6 C181 0.047 C182 0.047 VOLIN VOLOUT AFOUT VOLOUT AFOUT EXT.SP D17 RB706F-40 C240 47 P C239 0.001 R211 100 k C258 47 P R126 1 C180 0.0022 R128 47 k C179 1 R242 3.3 k R125 1M C178 0.
12-2 SW-A AND SW-B UNITS • SW-A UNIT S1 2 1 C 2 3 4 4 8 5 1 CP10 CP11 CP12 CP13 CP9 TP76N00N-15F-10KA-2251 R1 CP8 HV CP1 CP2 CP3 CP4 CP5 CP6 F1 Q1 XP4216 6 5 4 1 2 3 DS1 LNJ107W5PRW G RX (SQL OPEN) 4.1 V TX 0V CBI0 CBI1 CBI2 CBI3 CBI0 VOLOUT VOLIN RX (SQL OPEN) 4.8 V VCC TX 0V RLED TX 4.8 V RX (SQL OPEN) 0 V TLED GND RX (SQL OPEN) 0 V TX 4.1 V RX (SQL OPEN) 2.1 V TX 0V R2 330 R R3 560 RX (SQL OPEN) 0 V TX 2.
INTRODUCTION This service manual describes the latest service information for the IC-F21/IC-F21S at the time of publication. To upgrade quality, all electrical or mechanical parts and internal circuits are subject to change without notice or obligation. DANGER NEVER connect the transceiver to an AC outlet or to a DC power supply that uses more than 16 V. Such a connection could cause a fire hazard and/or electric shock. DO NOT expose the transceiver to rain, snow or any liquids.
SERVICE MANUAL VHF FM TRANSCEIVERS 1-1-32, Kamiminami, Hirano-ku, Osaka, 547-0003, Japan S-13717IZ-C1 © 2001 Icom Inc.
