1. Face the front of the radio towards you.
2. Remove the three screws in a row across the middle of the top of the radio.
3. Remove the two screws at the top rear (on the sides) of the radio.
4. Pry the top cover off from the back.
5. Disconnect the speaker at the connector.
   
   Modification:
   
    
6. Near the top rear of the main circuit board, there is an small, oblong metal can. Directly below the right side of this can is two surface mount diodes with a white silk-screened box around them. There is also what appears to be a circuit board part number just to the left of it (mine says B4916D). Remove the LEFT diode in the box.
7. To the left of this, there is a test point marked CP3. Just to the left and above this test point is another box with two *vertically* mounted surface-mount diodes (Note: there is also a place for 5 more *horizontally* mounted diodes, with 3 installed). Remove the LEFT vertically oriented diode.
   
   Reassembly:
   
    
8. Reconnect the speaker.
9. Put the top cover back on. Insert the top cover tabs into the slots and lower into position.
10. Replace all of the screws.

...
>Modification:
>6. Near the top rear of the main circuit board, there is an small, oblong
>metal can. Directly below the right side of this can is two surface mount
>diodes with a white silk-screened box around them. There is also what
>appears to be a circuit board part number just to the left of it (mine
>says B4916D). Remove the LEFT diode in the box.
>7. To the left of this, there is a test point marked CP3. Just to the left
>and above this test point is another box with two *vertically* mounted
>surface-mount diodes (Note: there is also a place for 5 more *horizontally*
>mounted diodes, with 3 installed). Remove the LEFT vertically oriented
>diode.

                              O<>O 7
                              O    O 6
                              O<>O 5
  J25                       O<>O 4
                              O<>O 3
                     O   O                                           O   O
                   1[]    [] 2                         B4916F   8[]   []9
                     O   O                                           O   O
                                 CP3
                                <__]


Diodes: 1,2,3,4,5,7,8,9 are instaled
Diode: 6 is not instaled

    d129
    ---- (d111 none)
    d112
    d113
    d114

d d                         d d
1 1                         1 1
1 1                         1 1
6 5                         8 9

D116 and D118 are responsible for out of band TX. D115 and D119 enables RX from 30KHz to 200MHz. D113 is responsible for 6M RX and D114 is responsible for 6M TX. I do not have info about D129 and D112.

Rafa3 SP6-1313WR, Klub SP6KBE :) Kontakt: jarel@box43.gnet.pl

TX range expansion on HF, VHF and UHF is very simple. When modified the radio will also transmit AM mode in the aircraft band with approximately 1 watt at 118 MHz to about 17 watts am carrier at 136 MHz.

On MAIN BOARD under speaker near Xtal you can see two rows of solder dots for SMD components. Only on position 10 (from left) is diode (D2030), which is necessary to remove.

Thats all.

After connecting power radio will be reseted and TX range is expanded.
 

These are the readings I took after performing the mod. I took readings at key frequencies throughout the band to measure the efficiencies of the different band pass filters, especially in the HF band. The attenuation at the edges of the filters are very visible especially at the 8MHz cross point.

All readings were took with a bird wattmeter and a home made RF voltmeter, the latter is not reliable over 200MHz.

Thanks. Olivier, VE2NSM.

It is based on information provided by ICOM Europe.

The level of the IC 706 MK II microfone amplification does not satisfy under certain circumstances like heavy pile up or operators with faint voice.

A litle modification does help to increase the amplification level a lot: The 5,6 k ohm SMD type resistor R235 located on the main unit has to be replaced by an approximately 1,0 k ohm type.

After modification the personal level of the microfone amplifier can be set in the initial setup (menue Q2).

1. To replace the resistor first open the top of the case by unsrewing the 3 screws in the middle and the 2 screws back on the left and right side. Remove the top carefully and disconnect the loudspeaker cable.
   
    
2. Locate the main unit ( the one near the display front side) and disconnect all connectors.
   
    
3. Locate the 5 screws holding the main unit and unscrew them.
   
    
4. Pull out the main unit and turn it over. This is the side of interest.
   
    
5. Locate the SMD resistor R325 and unsolder it. Solder in the approximately 1.0 k ohm type.
   
    
6. Reassemble the main unit.
   
    
7. A reset of the radio is not necessary.
   
    
8. Don`t forget to set your personal mic amp level in the initial setup (menue Q2).

Remarks:
 

Although I modified my own IC 706 MK II without any problems I certainly will not be responsible for any damage of your radio following this modification description. You are acting on your own risk.

vy 73

Juergen, DL5EBS

Es folgen 4 Bilder im *.gif - Format die den Umbau für 9k6 PR und Pactor beschreiben für den IC-706MKIIG.

Viel Spaß damit. Ich übernehme keine Haftung für evtl. entstehende Schäden am Transceiver !

Die 4 Dateien habe ich im PR-Netz gefunden.
 

Okay, I've got a new Icom IC-706MKIIG info for you:

There is a mod saying:

"Push P.AMP/ATT and RIT/SUB while power up and you will be able to see SHIFT-ADJ on your 706mkII. Dont know what this is for, recalibrating ?"

I have tested this and figured out the following:

When the SHIFT knob is in the middle position and you press SHIFT-ADJ, then "Good" is displayed. Nothing happens after power on.
But when you turn the SHIFT knob a little to the left or to the right, then good is displayed and next time you power up you have a modified shift adjustment. The SHIFT graph is different, too!

If you turn the knob a bit more to the left or to the right, then "Error" is displayed and nothing happens.

I wrote to Icom Europe and they say, that this function (P.AMP/ATT + RIT/SUB) is only used in the factory during the production process of the IC-706MKIIG. to calibrate the centersetting of the shift know.

Afterwards a new calibration shouldn't be necessary.
When you press the arrow in the SHIFT-ADJ menu for one second, the position of the shift know is stored as the new center setting.
 

The following adjustments are to increase the average talk power on SSB for the above radios. If your radio is still under warranty, check with your supplier to ensure warranty will not be invalidated

For both these adjustments you will need a very small cross-point screwdriver and a steady hand! Do not proceed if you are not confident!

Alinco DX70TH: Turn up the microphone gain as detailed in the manual. This should be set to maximum. The adjustments described here is concerned with the ALC control. ALC action is indicated by the TX light which should glow brighter when speaking into the microphone.

Remove the top cover and locate the high power/50w switch (this switch location is detailed in the manual, it is the only switch visible under the top cover). To the left of the switch there should be a small pot which is for the ALC. Just above the pot printed on the circuit board is 100w. Set the radio to 28Mhz and while speaking into the mike turn the pot counter clockwise until the TX light just fails to glow brighter. Back off slightly to restore the increase in brigthness of the TX light while speaking into the microphone. Replace the top cover.

This adjustment increases talk power considerably and for local contacts on SSB the compressor should be switched off.

Icom 706Mk2/Mk2G: The Icom 706 series are notorious for low talk power on SSB. A simple tweek of the ALC can solve the problem. This procedure was published in Radcom July 1999 but is updated here to include the IC706Mk2G. As far as I can ascertain, the later model 706MK2G seems not to suffer from the problem of low talk power and this mod may not be necessary. Remove the top cover. At the front edge of the main circuit board (to the left of the crystal filter slots, with the front of the radio facing you) should be a small pot. In the 706Mk2 this is R511 and in the 706Mk2G it is R579 (the number is not actually printed on the board!). The pot may be obscured by printed ribbon. This pot needs to be turned clockwise while speaking into the microphone, with power set to high and microphone gain at 6 (compressor should be switched off). Adjust for maximum talk power.

The article in Radcom claims that this adjustment will bring the 706Mk2 up to 100w pep without the need for the compressor. For the 706MK2G (early models), adjusting R579 can give a dramatic increase in talk power although you will find that you will still need to have the microphone gain turned up to 10 and the compressor switched on. On my own set I have noticed that some bands give more talk power than others. On 160, 80 and 2 meters I get nearly full power by speaking into the mike (gain at max and compression on). However on other bands the increased talk power is not so dramatic particulalry on 10, 20 meters).

Another way to boost the talk power on the 706 series is to use a preamplified microphone. If you do decide on a preamplified microphone reset R511/R579 back to it's original postion or distortion may result.

This article can also be found at http://www.qsl.net/g0fvi/adjust.html.
 

Hello. I found this picture on a Japanese website about how to mod the Japanese version of the IC-706MK2G. I recently bought a Japanese version of this radio. It seems that the Japanese version is a bit different when it comes to the diode configuration.

I did first remove the D2030 diode on my radio, but that did not open up the TX range. Then I removed the D2028 diode, and this opened up TX from 1,6-26 MHz and 28-30 MHz.

TX is still only 50-54 + 144-146 + 430-440 MHz on VHF/UHF. RX is now 0,030-200 MHz + 400-470 MHz. For my purposes it works fine with this range.

Later I found this picture on a Japanese site suggesting that only D2028 is to be removed on the Japanese version. I don't understand the Japanese text, so maybe someone can translate it ?

This mod is for the mic of a IC-706MK2. This allows better use of cw by installing a paddle in the mic.

Wire the contacts of a dissassembled relay with an isolated paddle (important) to the up down contacts and remove the old buttons from the small board and glue them in to the top of the mic to fill the holes

enjoy colin f5vhz
 

If you would like to increased receive on your 706mk2g, here is the procedure.

Take off top cover with front facing you. Behind the left of the VFO against the front of the case is 2 square cans with black Phillips screws in them. Don't adjust these, right behind them in the middle is a metal adjustment screw that looks like most of the other ones, like the adjustments for power etc.

Have your radio on SSB and turn clockwise and you will hear the receive increase. Only turn it a little, that does a lot, you don't want to over do it. Too much will bring in a lot of noise.

I've done it to mine and it really made the ears better than from the factory. As you know, the receive is great on these rigs, but this improves it more. It takes a jewelers flat head screwdriver, be careful. I'm not responsable if you mess up.

73s
 

This information will allow the use of an Icom HM-56A DTMF mic with an Icom 706. I have ONLY used this on my 706mkIIG so test it on all others at your own risk.

You will need an 8 conductor (RJ-45) ethernet connector (male) and a crimping tool. Radio shack has a non-crimp version if you don't want to invest $45 for a new tool.

If you place the tab down, pin 1 is the furthest to the left (see picture)

The color code is:
1. Red
2. Black
3. 
4. Green
5. Braid
6. 
7. Blue
8. 

I edited the out-of-band drawing to show the modification from American version to European version

This mod is for installing a International Radio #110 crystal filter