Vhf mobile transceiver, uhf mobile transceiver (36 pages)
Summary of Contents for Icom IC-2730A
Page 1
DUAL BAND TRANSCEIVER S-15120XZ-C1 March 2015...
Page 2
8. READ the instructions of the test equipment thoroughly before connecting it to the transceiver. Icom, Icom Inc. and the Icom logo are registered trademarks of Icom Incorporated (Japan) in Japan, the United States, the United Kingdom, Germany, France, Spain, Russia, Australia, New Zealand, and/or other countries.
Page 5
Receiver • Receive system: Double superheterodyne system • IF frequencies: Left band 1st IF 38.85 MHz 2nd IF 450 kHz Right band 1st IF 46.35 MHz 2nd IF 450 kHz • Sensitivity (except spurious points): Amateur bands FM/FM-N (12 dB SINAD) ...
Page 6
SECTION 2. INSIDE VIEWS • CONTROL UNIT +3.3 V REGULATOR (IC6) RESET IC (IC1) (IC5) +3.3 V REGULATOR (IC7) CLONING DATA LINE BUFFER (IC102) LCD DRIVER (IC2)
Page 7
• MAIN UNIT (TOP VIEW) RESET IC (IC308) CLONING DATA LINE BUFFER EEPROM (IC312) (IC301) NOISE AMP (Left band) (IC123) AND LOGIC GATE IC NOISE AMP (Right band) (IC108) (IC122) AF SW MIC MUTE SW/MIC GAIN SW (IC109) (IC100) ELECTRONIC VOLUME IC VOX AMP/IDC AMP/AF LPF (IC110) (IC112)
Page 8
• MAIN UNIT (BOTTOM VIEW) DISCRIMINATOR (Right band) (X101) 2ND IF FILTER (Right band) (FI101) 2ND IF FILTER (Right band) (FI100) TX POWER AMP (UHF band) (IC4) PLL IC (Right band) (IC206) REFERENCE FREQUENCY OSCILLATOR (Right band) (X201) DISCRIMINATOR (Left band) (X102) 2ND IF FILTER (Left band) (FI103)
Page 9
SECTION 3. DISASSEMBLY INSTRUCTION 1. Removing the CONTROL UNIT 2. Removing the MAIN UNIT 1) Remove all knobs from the controller. 1) Remove eight screws from the top cover. 2) Remove the top cover from the chassis. Controller Screws ×8 Top cover 2) Remove four screws from the rear panel.
Page 10
6) Unsolder three points at the antenna connector. 7) Disconnect the cooling fan cable. UNSOLDER COOLING FAN CABLE Solder remover 8) Remove total of 17 screws from the MAIN UNIT. Screws ×17 9) Remove the MAIN UNIT from the chassis. MAIN UNIT CHASSIS...
SECTION 4. CIRCUIT DESCRIPTION 4-1 RECEIVE CIRCUITS RF CIRCUITS RF CIRCUITS The received signal from the antenna connector passed ANTENNA through the LPF (L90, L94, L96, C409, C418 and C428). The D68,D73, 375-550MHz 118-550MHz D84,D75 fi ltered signal is applied to either the VHF or UHF band’s RF TX/RX 400-470MHz UHF TX circuit...
Page 12
1ST IF CIRCUITS 2ND IF CIRCUITS VHF BAND • Left band • Left band IC121 is an IF IC, which contains the 2nd mixer, limiter AMP, The received signal from the RF circuit and 1st LO signal are noise AMP, quadrature detector, AM detector, AGC controller, applied to the 1st IF mixer (Q145) and mixed, resulting in the signal strength detector, and so on.
Page 13
AM DETECTOR CIRCUITS • Left band 2ND IF AND DEMODULATOR CIRCUITS (Left band) The 2nd IF signal applied from pin 5 is amplifi ed by the IF X200 Q200 AMP, and then demodulated by the amplitude detector in the 38.4MHz 12.8MHz IF IC (IC121).
Page 14
RX AF CIRCUITS • Left band When output from [EXTERNAL SPEAKER JACK1] The demodulated AF signal from the AF SW (IC119) is The output signal from the AF SW (IC109) is passed through passed through the AF mute SW (IC111, pins 4, 3) and AF fi l- the AF MUTE SW (Q104 and Q105), and applied to the AF ter (Q113), and then applied to the volume IC (IC110, pin 4), AMP (IC105, pin 1).
4-2 TRANSMIT CIRCUITS TX AF CIRCUIT (CONTROL AND MAIN UNITS) MODULATION CIRCUITS (MAIN UNIT) When the microphone is connected to the controller: The modulation signal from the TX AF circuit is applied to the The AF signal from the microphone is applied to the MIC VCO as the frequency modulation signal.
Page 16
TX AMP CIRCUITS (MAIN UNIT) APC CIRCUITS VHF BAND VHF BAND The TX signal from the VHF band modulation circuit is passed A portion of RF signal is rectifi ed by the power detector di- through the LPF (L50, L51, C215, C220 and C225) and ATT odes (D59 and D63) at the LPF (L67, L68, C291, C297, (R146, R147 and R151), and then sequentially amplifi...
VCOs The PLL circuit controls the VCO oscillating frequency by The IC-2730A/E has total of four VCOs: two VCOs for the left comparing the reference signal and the fed back VCO sig- band and another two for the right band.
4-4 VOLTAGE BLOCK DIAGRAM Voltage from the power supply is routed throughout the transceiver, through regulators and switches. W300 NOISE FANHV FILTER Q32/Q34 I SENS UTX_C IC310 CURRENT IDET DETECT Q27/Q28 VTX_C Q306 IC313 Q301/Q308 PCON CTRL VCC2 Q302 IC325 IC319 IC321 MAIN UNIT...
–20 dBµ to 90 dBµ (–127 dBm to –17 dBm) DO NOT transmit while Attenuator an SSG is connected to deviation meter 40 dB the antenna connector. RF power meter 0.1–60 W/50 Ω Frequency IC-2730A/E (Rear view) counter...
Page 20
5-1 PREPARATION (Continued) Select an adjustment item using [MONI]/[LOW], and then set the adjustment value as specifi ed using [DIAL]. • ENTERING THE ADJUSTMENT MODE 1) Connect the JIG cable to [MIC] on the main unit. (See page 5-1.) 2) While holding down both [MAIN BAND], turn ON the power. Main unit (front view) 1) Connect the JIG cable to [MIC].
5-2 FREQUENCY ADJUSTMENT Select an adjustment item using [DUP MONI]/[LOW DTMF], and then set the adjustment value as specifi ed using [DIAL]. ADJUSTMENT ADJUSTMENT OPERATION VALUE ITEM REFERENCE 1) Connect a power meter or dummy load to the antenna connec- FREQUENCY tor.
Page 22
5-3 TRANSMIT ADJUSTMENTS (Continued) Select an adjustment item using [DUP MONI]/[LOW DTMF], and then set the adjustment value as specifi ed using [DIAL]. ADJUSTMENT ADJUSTMENT OPERATION VALUE ITEM 1 1) Connect a modulation analyzer to the antenna connector through MODULATION BALANCE an attenuator, and then set it as;...
5-4 RECEIVE ADJUSTMENTS 1) Select an adjustment item (band) using [DUP MONI]/[LOW DTMF]. 2) Set the SSG’ frequency as specifi ed, and then push [MW] to automatically adjust. ADJUSTMENT ADJUSTMENT OPERATION VALUE ITEM RECEIVE NOTE: “RECEIVE SENSITIVITY” must be adjusted before “S-METER.” Otherwise, “S-METER” will SENSITIVITY not be adjusted properly.
Page 24
5-4 RECEIVE ADJUSTMENTS (Continued) ADJUSTMENT ADJUSTMENT OPERATION VALUE ITEM S-METER NOTE: “RECEIVE SENSITIVITY” must be adjusted before “S-METER.” Otherwise, “S-METER” will not be adjusted properly. 1 • Connect an SSG to the antenna connector, and then set it as: – –...
Page 25
5-4 RECEIVE ADJUSTMENTS (Continued) ADJUSTMENT ADJUSTMENT OPERATION VALUE ITEM -435.020/450.020 MHz- 38 • Set the SSG as: Push [MW]. [S39] (NAR) Frequency: (Set the same frequency displayed on the controller.) (FM-N mode) (Automatic [Left band] † Level 0 dBµ (–107 dBm) adjustment) [Right band] [S39] (NAR)