[ICOM] Mic gain on the 706 MKIIG

[D C *Mac* Macdonald]

Every MkIIg I have encountered needs to have mic gain
turned down for FM.  Deviation is set, as Cliff says, by the
deviation pot.  HOWEVER, unless mic gain is reduced,
the FM audio will be  GROSSLY  overdriven into distortion.

There may be an op-amp stage somewhere in the FM audio
chain that could stand to have a feedback chip resistor
changed out so that a single mic gain setting would be
satisfactory for both SSB and FM.  The feedback path
is "ususally" negative, so that the resistor will need to be
reduced to obtain MORE negative feedback, thereby
cutting the stage gain.

I did this on a "long ago" Icom FM rig to cut the overdrive.
And no, I don't remember which rig it was, but it  MAY
have been IC-25 or IC-27.

Mac, K2GKK/5

----Original Message Follows----
From: "ed yeary" <w4tey at bellsouth.net>
Reply-To: ICOM Reflector <icom at mailman.qth.net>
To: "ICOM Reflector" <icom at mailman.qth.net>
Subject: Re: [ICOM] Mic gain on the 706 MKIIG
Date: Wed, 31 May 2006 11:25:43 -0400

Are you sure about this?
Ed Yeary W4TEY


----- Original Message ----- From: "Clif Holland" 
<radio.service at verizon.net>
To: "ICOM Reflector" <icom at mailman.qth.net>
Sent: Wednesday, May 31, 2006 11:24 AM
Subject: Re: [ICOM] Mic gain on the 706 MKIIG

>The mike gain setting has nothing to do with FM deviation. Deviation is set 
>by an internal pot. The front panel Mike Gain setting is for SSB.
>
>Clif Holland KA5IPF
>www.avvid.com