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Icom IC-2720H Service Manual

Other manuals for IC-2720H: Instruction Manual, Operating Manual
Manual is about: DUAL BAND FM TRANSCEIVER

Summary of IC-2720H

  • Page 1

    Dual band fm transceiver i2720h service manual.

  • Page 2

    Introduction this service manual describes the latest service information for the ic-2720h dual band fm transceiver at the time of publication danger never connect 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 tran...

  • Page 3

    Table of contents section 1 specifications section 2 inside views section 3 disassembly instructions section 4 circuit description 4 - 1 receiver circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 - 1 4 - 2 transmitter ci...

  • Page 4: Section 1

    1 - 1 section 1 specifications all stated specifications are subject to change without notice or obligation. M general • frequency range : left side right side * 1 guaranteed 144.000 – 146.000 mhz only, * 2 guaranteed 144.000 – 148.000 mhz only, * 3 guaranteed 430.000 – 440.000 mhz only; * 4 guarant...

  • Page 5: Section 2

    Section 2 inside views 2 - 1 • control unit (top view) key back light (ds14, ds15: ln1371g) lcd back light ds1-3, ds7-9: sml-010mt ds4-6, ds10-12: sml-020mlt key back light (ds16, ds17: ln1371g) key back light (ds15, ds18: ln1371g) key back light (ds14, ds15: ln1371g) lcd back light ds1-3, ds7-9: sm...

  • Page 6

    • control unit (bottom view) dimmer +8v regurator (q1: 2sc4116) +5v regurator (ic3: ta78l05f) sub cpu (ic4: hd6473847rh) reset ic (ic2: s-80945clmc) data comparator (ic1: ta75s01f) mic amplifier ic5: ta75s558f q15: 2sc4116 dimmer circuit (q6-q13: 2sc4116) +8v regurator q1: 2sc4116 q3: 2sa1586 d1: ma...

  • Page 7: Section 3

    Section 3 disassembly instructions • removing the main unit ➀ unscrew 8 screws a , and remove the cover. ➁ disconnect two cables b from j1 and j2007. ➂ remove the clip c . A a b c j2007 j1 g f g f h e main unit j i ➃ unsolder 3 points e . ➄ unscrew 4 screws f . ➅ unsolder 4 points g , and remove the...

  • Page 8

    • removing the control unit ➀ remove 6 knobs a . A a ➁ unscrew 4 screws b , and remove the cover. ➂ remove the plate c , and remove control unit. B c control unit 3 - 2.

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    4 - 1 section 4 circuit description 4-1 receiver circuits 4-1-1 triplexer and rx band switching circuits (main unit) the transceiver has a triplexer (low-pass and high-pass fil- ters) on the first stage from the antenna connector to sepa- rate the signals into vhf and uhf signals. The rf signals fro...

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    4 - 2 the signals from the rx band swtiching circuits are then applied to the left side displayed 1st mixer circuit (ic1005, pin 6). 4-1-3 1st mixer and 1st if circuit for left side display (main unit) the 1st mixer circuit converts the received rf signals to a fixed frequency of the 1st if signal w...

  • Page 11

    4 - 3 a portion of the af signals from the fm if ic (ic1001, pin 9) are applied to the active filter section (ic1001, pin 8). The active filter section amplifies and filters noise components. The filtered signals are applied to the noise detector section and output from the ic1001 (pin 14) as the “l...

  • Page 12

    4 - 4 the 46.05 mhz 1st if signal from the if amplifier (q1041) is applied to the 2nd mixer section of the fm if ic (ic1004, pin 16), and is mixed with the 2nd lo signal (45.595 mhz) to be converted to a 455 khz 2nd if signal. The 2nd if signal is applied to the each demodulator circuits by am or fm...

  • Page 13

    4-2 transmitter circuits 4-2-1 microphone amplifier circuit (main and control units) the microphone amplifier circuit amplifies audio signals from the microphone to a level needed for the modulation circuit. The microphone amplifier circuit is commonly used for the both vhf and uhf bands. • the af s...

  • Page 14

    4 - 6 4-2-5 apc circuit (main unit) the apc circuit protects the pre-drive (q21), drive amplifier (q25) and power amplifier (q27) from a mismatched output load and stabilizes the output power. • vhf apc circuit the swr detector circuit (d57, d61) detects forward signals and reflection signals at d57...

  • Page 15

    4 - 7 • uhf-vco the oscillated signal at the uhf-vco circuit is amplified at the buffer amplifiers (q1044, q1047), and is then applied to the vco switch (d2059, d2060) to divide uhf tx signal and rx signal. (1) uhf tx signal the tx uhf signal passes through the high-pass filter (l1079, c2183, c2184)...

  • Page 16

    (1) normal oscillating signal circuit the signal from the vco swtich (d7) passes through the attenuator (r33, r37, r38, c41) and low-pass filter (l5, l9, c45, c47, c53, c63, c64), and then applied to the vco swtich (d10) which is controlled by the “l_vr5” signal. (2) twice oscillating signal circuit...

  • Page 17

    4 - 9 description the 13.8v external dc power from the power connector. The same voltage as the hv line which is con- trolled by the vcc regulator circuit (main unit; q2001). When the [power] switch is pushed, the cpu outputs control signal to the power switch controller (q2003) to turn the circuit ...

  • Page 18

    4 - 10 outputs microphone mute signal for right side display. Low: while microphone is muting. Output clock shift signal. Outputs transmit mute control signal. High:while transmit is muting. Input port for microphone’s ptt detect- ing signal. Outputs sub band select signal. Outputs rf transmit power...

  • Page 19

    4 - 11 outputs shift signal to the 430 mhz bandpass filter for left side display. High:while receiving 310–450 mhz on left side display. Outputs the 430 mhz receiver circuit select signal for right side display. Low: while receiving 360–549.990 mhz on right side display. Outputs the 144 mhz receiver...

  • Page 20: Section 5

    [control unit] [control unit] ic1 1110002750 s.Ic ta75s01f (te85r) ic2 1110005780 s.Ic s-80945clmc-g7f-t2 ic3 1180000420 s.Ic ta78l05f (te12r) ic4 1140010230 s.Ic hd6473847rh (fx-2493d) ic5 1130007370 s.Ic ta75s558f (te85l) q1 1530002690 s.Transistor 2sc4116-gr (te85r) q2 1590001650 s.Transistor xp4...

  • Page 21

    S.=surface mount [main unit] [control unit] c48 4550000530 s.Tantalum tesva 1v 104m1-8l c49 4550005980 s.Tantalum temsva 1a 475m-8l c50 4550003220 s.Tantalum temsva 1e 105m-8l c54 4550006250 s.Tantalum temsva 1a 106m-8l j1 6510023110 connector 3008l-8p8c j2 6510023170 connector 3008l-6p6c ds1 504000...

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    S.=surface mount [main unit] [main unit] q1021 1530002690 s.Transistor 2sc4116-gr (te85r) q1022 1590001190 s.Transistor xp6501-(tx) .Ab q1023 1530002850 s.Transistor 2sc4116-bl (te85r) q1025 1590001190 s.Transistor xp6501-(tx) .Ab q1026 1590001650 s.Transistor xp4601 (tx) q1027 1590001650 s.Transist...

  • Page 23

    S.=surface mount [main unit] [main unit] d2063 1790001620 s.Diode 1sv308 (tpl3) d2064 1790001620 s.Diode 1sv308 (tpl3) d2065 1790001620 s.Diode 1sv308 (tpl3) d2066 1790001620 s.Diode 1sv308 (tpl3) d2067 1790001620 s.Diode 1sv308 (tpl3) d2068 1790001620 s.Diode 1sv308 (tpl3) d2069 1790001250 s.Diode ...

  • Page 24

    S.=surface mount [main unit] [main unit] r32 7030003280 s.Resistor erj3geyj 470 v (47 Ω ) r33 7030000220 s.Resistor mcr10ezhj 47 Ω (470) r38 7030003260 s.Resistor erj3geyj 330 v (33 Ω ) r39 7030003260 s.Resistor erj3geyj 330 v (33 Ω ) r40 7030003670 s.Resistor erj3geyj 823 v (82 k Ω ) r41 7030003670...

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    S.=surface mount [main unit] [main unit] r1030 7030003530 s.Resistor erj3geyj 562 v (5.6 k Ω ) r1031 7030003580 s.Resistor erj3geyj 153 v (15 k Ω ) r1032 7030003580 s.Resistor erj3geyj 153 v (15 k Ω ) r1033 7030003500 s.Resistor erj3geyj 332 v (3.3 k Ω ) r1034 7030003500 s.Resistor erj3geyj 332 v (3...

  • Page 26

    S.=surface mount [main unit] [main unit] r1285 7030003470 s.Resistor erj3geyj 182 v (1.8 k Ω ) r1286 7030003510 s.Resistor erj3geyj 392 v (3.9 k Ω ) r1288 7030003640 s.Resistor erj3geyj 473 v (47 k Ω ) r1289 7030003640 s.Resistor erj3geyj 473 v (47 k Ω ) r1290 7030003320 s.Resistor erj3geyj 101 v (1...

  • Page 27

    S.=surface mount [main unit] [main unit] r2236 7030003520 s.Resistor erj3geyj 472 v (4.7 k Ω ) r2237 7030003760 s.Resistor erj3geyj 474 v (470 k Ω ) r2238 7030003680 s.Resistor erj3geyj 104 v (100 k Ω ) r2239 7030003520 s.Resistor erj3geyj 472 v (4.7 k Ω ) r2240 7030003760 s.Resistor erj3geyj 474 v ...

  • Page 28

    S.=surface mount [main unit] [main unit] c162 4030006860 s.Ceramic c1608 jb 1h 102k-t c163 4030006860 s.Ceramic c1608 jb 1h 102k-t c164 4030006860 s.Ceramic c1608 jb 1h 102k-t c165 4030006910 s.Ceramic c1608 ch 1h 0r5c-t c166 4030009470 s.Ceramic c1608 ch 1h r75c-t c167 4030006860 s.Ceramic c1608 jb...

  • Page 29

    S.=surface mount [main unit] [main unit] c1062 4550003220 s.Tantalum temsva 1e 105m-8l c1063 4030006860 s.Ceramic c1608 jb 1h 102k-t c1065 4030006900 s.Ceramic c1608 jb 1h 103k-t c1066 4030006960 s.Ceramic c1608 ch 1h 050c-t c1067 4030006900 s.Ceramic c1608 jb 1h 103k-t c1068 4030006900 s.Ceramic c1...

  • Page 30

    S.=surface mount [main unit] [main unit] c2037 4030006860 s.Ceramic c1608 jb 1h 102k-t c2038 4510006240 s.Electrolytic ecev1ca221p c2039 4510006260 s.Electrolytic ecev1aa471up c2040 4510006220 s.Electrolytic ecev1ca101up c2041 4510004640 s.Electrolytic ecev1ca470sp c2042 4030011600 s.Ceramic c1608 j...

  • Page 31

    S.=surface mount [vco unit] [main unit] j1 6510014960 s.Connector b2b-zr-sm3-tf j2001 6510023110 connector 3008l-8p8c j2003 6510023160 connector dn-508b-6 j2004 6450002220 connector pj-0008p-5 j2005 6450001440 connector hsj1403-01-010 j2006 6510023170 connector 3008l-6p6c j2007 6510014960 s.Connecto...

  • Page 32

    S.=surface mount [vco unit] [vco unit] r29 7030003640 s.Resistor erj3geyj 473 v (47 k Ω ) r30 7030003440 s.Resistor erj3geyj 102 v (1 k Ω ) r31 7030003520 s.Resistor erj3geyj 472 v (4.7 k Ω ) r32 7030003560 s.Resistor erj3geyj 103 v (10 k Ω ) r33 7030003210 s.Resistor erj3geyj 120 v (12 Ω ) r34 7030...

  • Page 33: Section 6

    Section 6 mechanical parts and disassembly 6 - 1 j1 6510004880 connector mr-ds-e 01 1 sp1 2510001160 speaker 057p0802 1 mf1 2710000730 fan ad0412hb-g70 (ts) 1 mp1 8010018850 2493 chassis 1 mp2 8110007720 2493 cover 1 mp3 8930057750 2493 sp holder 1 mp4 8110005750 1729 fan cover 1 mp5 8930044761 2055...

  • Page 34

    6 - 2 mf1 (c) j2004 (m) j2005 (m) mp4 (c) mp11 (c) mp9 (c) j1 (c) w2 (m) mp5 (m) mp12 (c) mp13 (c) mp1 (c) mp11 (ct) mp2 (ct) mp11 (ct) mp10 (ct) r3 (ct) r1 (ct) j2 (ct) s1 (ct) r5 (ct) r7 (ct) s2 (ct) j1 (ct) mp3 (ct) mp13 (ct) mp9 (ct) mp7 (ct) mp6 (ct) mp8 (ct) ep15 (ct) ds19 (ct) control unit vc...

  • Page 35

    Section 7 semi-conductor information • transsistors and fet’s • diodes b e c b e c b c e b e c b e c b e c b e c b e c b e c b e c b e c b e c e c b e s d g g s d s g s d g1 g2 s d g1 g2 s d g1 g2 s d g s d s b e c b e c b e c b e c b e c b e c e1 c2 b1 c1 e2 b2 e1 c2 b1 c1 e2 b2 e1 e2 b2 c1 b1 c2 2...

  • Page 36

    Section 8 board layouts 8-1 control unit • top view main band v/mhz scan m/call mw main band v/mhz scan m/call mw dup moni tone dtmf low prio sql dial dial sql vol set vol pwr hv 6 4 2 to main unit j2006 5 3 1 j2 rdata mic tdata gnd mice 2 4 6 8 to microphone 1 3 5 7 j1 micu/d ptt mic micin 8v extmi...

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    • bottom view (control unit) 1 100 50 51 25 26 76 75 8 - 2.

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    Sp+ 1 to speaker 2 j2007 gnd fa n + 1 to fan 2 j1 fa n - 1 12 1 1 12 24 13 25 26 50 51 75 76 100 l_rxlo gnd l_vr5 l_ur5 ref_con 5vs to vco unit j5 out1 plld a t a pllck ref_osc l_lo_sw 8v ref_mod l_pllsw l_unlock to vco unit j2 to vco unit j3 to vco unit j4 mod l_vco_shift out4 gnd l_vco8 l_txlo to ...

  • Page 39

    7 8 2 1 to microphone to control unit j2 j2001 gnd mice extmic 8v micin mic ptt micu/d 4 2 1 6 5 3 to external equipment j2003 dataout gnd datain pttp psql afout 6 5 1 2 j2006 cthv rdata mic txdata gnd mice 1 8 5 1 4 7 14 8 8 14 7 1 1 7 14 8 9 16 8 1 16 9 1 8 1 4 8 9 16 8 1 5 5 8 4 1 1 10 20 11 1 4 ...

  • Page 40

    8-3 vco unit • top view 1 8 16 9 1 4 8 5 8 - 5.

  • Page 41

    L_rxlo 1 6 j5 gnd l_vr5 l_ur5 ref_con 5vs out1 1 3 j2 plld a t a pllck ref_mod 3 1 j4 l_pllsw l_unlock ref_osc 3 to main unit 1 j3 l_lo_sw 8v l_txlo 6 1 j1 l_vco8 gnd out4 l_vco_shift mod to main unit to main unit to main unit to main unit • bottom view (vco unit) 8 - 6.

  • Page 42

    Section 9 block diagram 9 - 1 mod r_wxalt l_det_mute l_dtcs_in l_wxalt r_sql r_rssi r_dtcs_in r_det_mut l_rssi l_sql af_vol_data da_stb,da_ck,da_data r_wxalt l_det_mute l_dtcs_in l_wxalt l_vco_shift out4 r_sql af_vol_ck dtcs dtcs_sel l_pllsw r_rssi r_dtcs_in r_det_mut l_rssi l_sql l_sql l_rssi r_rss...

  • Page 43

    Vatt l_bpf1 l_bpf2 r400_shift vu2 uu1 l_bpf1 l_bpf2 vu1 l_bpf1 l_bpf2 uv vatt l_bpf3 l_bpf1 l_bpf2 l_bpf4 vatt l_bpf3 l_bpf1 l_bpf4 l_bpf2 uif vif uatt r_bpf1 r_bpf2 r_bpf4 r_bpf3 vatt l_bpf3 l_bpf2 l_bpf1 l_bpf4 l_bpf3 l_bpf4 l_bpf2 l_bpf1 vatt vagc uagc vif uif micin mic mice extmic micu/d mic mic...

  • Page 44

    Section 10 voltage diagrams 10-1 control unit 10 - 1 power power 8v 8v mice mice hv mice mice mice 8v hv hv hv hv hv hv hv hv unit j2006 to main to microphone control unit mic ptt micin 13.32v 7.97v 5.04v p60/seg9 1 c23 2sc4116 q12 2sc4116 q10 2sc4116 q8 1k r44 1k r48 2sc4116 q6 1k r52 1k r56 2sc411...

  • Page 45

    10-2 main and vco units 10 - 2 hv wn_sel hv hv hv hv hv hv hv dtcs dtmf l_wxalt r_wxalt l_dtcs_in l_sql r_dtcs_in r_sql rev_det temp l_rssi r_rssi mic_sel cm_mute dataout afout p_sql p_ptt datain datain pttp dataout psql afout temp temp p_lr_sel datain afout data xp4601 q2014 main unit(1) rx: 4.79v ...

  • Page 46

    Ref_osc refcon 5vs 5vs 8v 8v 8v l_unlock ref_mod l_vco8 refcon 5vs 5vs ref_con l_vr5 l_rxl0 l_ur5 udets 8v l_det_mute vdets 8v pllck mod_set_data 8v 5vs 5vs 8v 5vs 5v hv bus line2 bus line1 8v 5vs 5v hv bus line2 bus line1 hvc321b d3 refcon 5vs 8v 5vs 5vs rx: 3.87v 4.68v rx: 0.58v 7.11v rx: 4.67v rx...

  • Page 47

    Bus line1 vagc uagc vagc 8v 5vs 5v hv bus line2 8v 8v 5vs 5v hv bus line2 bus line1 bus line4 10k r2265 0.001 c2210 c1072 0.001 rx: 0.23v uhf tx: 0.0v vhf tx: 0.24v rx: 4.62v uhf tx: 0.11v vhf tx: 4.62v rx: 0v tx: 0v rx: 5.0v tx: 5.0v rx: 7.9v tx: 7.9v rx: 6.38v tx: 6.38v rx: 6.8v tx: 6.8v rx: 0v tx...

  • Page 48

    Hv rev_det u-u3 (810-1000mhz) v-u2 (375-500mhz) u-u (375-500mhz) l_bpf4 l_bpf3 r800_r5 r800_r5 vu2 l400_r5 r_r5 vatt uatt r_r5 uu1 r400_r5 r_r5 uatt bus line4 5vs vatt hv hv tx_mute 8v 5vs 5vs 5vs 5vs 5vs 5vs 5vs 5vs 8v hv 5vs hv 8v 5v hv l k dan222 d1041 dan222 d1040 l400_r5 l300_r5 l220_r5 l140_r5...

  • Page 49

    V-v(118-180mhz) j1 chassis u-v (136-174mhz) v220 (174-260mhz) v-u(225-375mhz) l_bpf1 r_bpf1 r_bpf2 r_bpf3 r_bpf4 r140_r5 uv l_bpf1 l_bpf2 l_bpf3 l_bpf4 5vs vv l140_r5 5vs bus line2 5vs rx: 0.15v tx: 0.08v rx: 3.58v uhf tx: 3.64v vhf tx: 0v rx: 0v tx: 0v rx: 0v tx: 0v rx: 2.73v rx: 3.72v 5vs main uni...

  • Page 51

    1-1-32, kamiminami, hirano-ku, osaka 547-0003, japan s-13907hz-c1 © 2002 icom inc..