E:\Ham Radio 090506\Icom\IC-2340H\ic-2340h-mods.php.htm ------------------------------------------------------- Icom IC-2340H (IC 2340 H IC2340H) Programming interface schematics for Icom: Programming software for Icom IC-2340H (IC 2340 H IC2340H) : PDF User Manual for Icom IC-2340H (IC 2340 H IC2340H) : PDF Service Manual with schematics for Icom IC-2340H (IC 2340 H IC2340H) : Mods for Icom IC-2340H (IC 2340 H IC2340H) : Icom IC-2340H (IC 2340 H IC2340H) Some mods Icom IC-2340H (IC 2340 H IC2340H) mods Icom IC-2340H (IC 2340 H IC2340H) att modification Icom IC-2340H (IC 2340 H IC2340H) technical specifications : Icom IC-2340H (IC 2340 H IC2340H) technical specifications Icom IC-2340H (IC 2340 H IC2340H) mods Symptom: Any of the following: Cannot change band to UHF, no UHF volume or squelch control, no UHF tuning, or strange-sounding beep tone. Cure: Rework bad soldering at J3 on display unit and replace the SW-B board with a factory-modified flex PC board. -------------------------------------------------------------------------------- Symptom: No audio output from receiver. Cure: Remove excessive solder on the Main-A unit near the audio amp. -------------------------------------------------------------------------------- Symptom: Howling if volume is turned up when using UHF. Probable Cause: Microphonics in VCO section. Resolder the ground spring at the UHF VCO shield. You may also add a second spring for further improved resistance to microphones ================================================================================= Icom IC-2340H (IC 2340 H IC2340H) Programming interface schematics for Icom: Programming software for Icom IC-2340H (IC 2340 H IC2340H) : PDF User Manual for Icom IC-2340H (IC 2340 H IC2340H) : PDF Service Manual with schematics for Icom IC-2340H (IC 2340 H IC2340H) : Mods for Icom IC-2340H (IC 2340 H IC2340H) : Icom IC-2340H (IC 2340 H IC2340H) Some mods Icom IC-2340H (IC 2340 H IC2340H) mods Icom IC-2340H (IC 2340 H IC2340H) att modification Icom IC-2340H (IC 2340 H IC2340H) technical specifications : Icom IC-2340H (IC 2340 H IC2340H) technical specifications Icom IC-2340H (IC 2340 H IC2340H) Some mods The diodes D12 to D20 and D10 + D8 on the logic board is the diodes that control frequencyrange and model version. [Logic board] -----------------------------------------------------------------------------------+ ------ | W1 | | | J 7 D14 D15 D12 D13 | +-------------------------------+ +----+ +----+ +----+ +----+ | | | | | | | | | | | | | | +----+ +----+ +----+ +----+ | +-------------------------------+ | +-----+ +----+ +----+ +----+ | | | | | | | | | | +-----+ +----+ +----+ +----+ | D18 D19 D16 D17 | | +---------+ +--------+ | | | | | | +---------+ +--------+ | D10 D8 | -----------------------------------------------------------------------------------+ Minirepeater: Remove D16 on logic board. (Not necessary on USA version) Set the desired QRG on each band. Push the [VHF MAIN] + [UHF MAIN] VFO knob and push [SET] at the same time. The memory channel indication changes to "L" (L=Minirepeater mode) To return to normal, push and hold [SET]. Expand RX for the EUR version: By key funktion: Switch off the radio. Push the [V/MHz] (for VHF), and [SET] and [DN] on microphone at the same time, while turning on power. By diode: Remove D17 diode on the logic board. Do a full reset by switching off the radio. Then while pushing [SET] + [SPCH], turn on the radio. After either mod, you will have: 118,000 - 135,995 MHz AM 136,000 - 174,000 MHz FM 320,000 - 479,000 MHz FM 830,000 - 950,000 MHz FM (Needs extra coaxial cable to receive anything) Expand RX for the USA version: Cut W1 jumper wire on logic board. After mod, you will have: 118,000 - 135,995 MHz AM 136,000 - 174,000 MHz FM 320,000 - 479,000 MHz FM ================================================================================= E:\Ham Radio 090506\Icom\IC-2340H\ic-2340h-att-modification.php.htm ------------------------------------------------------------------- Icom IC-2340H (IC 2340 H IC2340H) Programming interface schematics for Icom: Programming software for Icom IC-2340H (IC 2340 H IC2340H) : PDF User Manual for Icom IC-2340H (IC 2340 H IC2340H) : PDF Service Manual with schematics for Icom IC-2340H (IC 2340 H IC2340H) : Mods for Icom IC-2340H (IC 2340 H IC2340H) : Icom IC-2340H (IC 2340 H IC2340H) Some mods Icom IC-2340H (IC 2340 H IC2340H) mods Icom IC-2340H (IC 2340 H IC2340H) att modification Icom IC-2340H (IC 2340 H IC2340H) technical specifications : Icom IC-2340H (IC 2340 H IC2340H) technical specifications Icom IC-2340H (IC 2340 H IC2340H) att modification This text deals with ICOM's Mobile radio IC2340H. On some of icom dual band mobile transceivers there is an RF attenuator which attenuates the received signal by 20dB. In my opinion this is a great feature especially when you operate in cities or in area's with lot of RF signals, repeater, etc. The attenuator function reduce the intermodulations that appears while receiving in those areas, and let you listen more quietly on your favorite channel, when you listen to a local repeater you can hardly feel the 20dB attenuator, but the intermodulations almost disappear. The problem is that the attenuator was featured on old icom mobile rigs (such as IC2340H, IC3230H), but not on the IC2340H. The next lines will guide you how to add this feature. All you need is 2 1p2t small switch, and 2 12Kohms resistors. VHF MODIFICATION Open the upper cover of the transceiver. Locate D9 on the print (left to the Power Amplifier while looking from the front of the transceiver) Solder a 12K resistor to the anode of D9 as close as possible to the diode, (with no wire, the pin of the resistor should be soldered to the pin of the diode) The other side of the resistor should be wired to the small switch (the switch can be mounted on the back of the transceiver, there's an hole in the heatsink which you can use to insert the wires to the transceiver. The other side of the switch should be tied to 5V (you can find a 5V terminal at J2 pin 2, j2 & j1 located near the VCO at the front of the print it is a 2*4pin sip connector, j2 is closer to the VCO. UHF MODIFICATION Open the lower cover of the transceiver. Locate D17 on the board (this diode is wired under the board, just beside L22. there are 2 holes, I am talking about the one located closer to the antenna) Solder another 12K resistor in the same way it was done in the vhf to the anode of D17 just under the print ( the anode is the left pin of the diode ,the pin which located closer to the power amplifier. The other side of the resistor should be wired to the other small switch... The other side of the switch should be tied to 5V (for example to the right pin of the regulator IC7) Explanation When you turn this switch on, it turns the diodes on, and attenuates the received signal. This modification was tested, but you will do it on your own risk. ==================================================================================