I recently got hold of another IC-706 MKII, ( my first love ) and i noticed the the modulation was not satisfactory, i mean low talk power on SSB and faint modulations on FM, after performing a complete check up of the rig using the Service Manual and adjusting the whole for peak performance what left to be desired was the modulation, still low expecially on FM compared to my Alinco DR 605 V-U rig.
Well if you are encountering my same request, just perform these simple changes on the original microphone.
Work on a wide table covered with a cloth ( jumping springs inside ;-) )
Open up the the microphone removing the 3 screw on the back. Carefully lift the two shells apart, watch out the the PTT spring does not jump out.
Remove the 2 screws that hold the small PCB holding the microphone capsule.
Unsolder the original capsule and change with any other commercially available or salvaged from older cordless phone, mobile phone etc.
Solder the new capsule ( make sure that polarity is correct, the ground of the capsule should be soldered in the pad close to the center of the PCB just in case you forgot where it was, and the positive towards the left side of the hole for the capsule.
TADA!! mods is over.
Reassemble the lot and i'am 100% sure that you will notice the new stronger modulation. Adjust with the Mic Gain to your taste.
For those with weak voice level, try also to open the metal lid inside the microphone and remove the rubber disk inside, that gives better response to high tones.
All feedback would be appreciated.