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Icom IC-2200H TX preamp modification

AudioShockwav

Extraterrestrial
Staff member
Apr 6, 2005
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Nor Cal Sierra Nevada
The IC-2200H has minimal "sensitivity" to the point that it is hard to achieve enough audio in what is sometimes a quiet area, such as a home.
This modification electrically increases the output of the radio's internal mic preamplifier section. The attached picture's NUMBERS in brackets () will further describe the steps.
To complete this modification, you must remove the front control panel of the radio, and locate the area that is shown in the attached pictures. The un-used solder pads will be used to bridge in an unused (In the USA models) resistor with a series resistor that will be soldered to the unused pads; The overall result will change the feedback resistor assignments. This will add more gain to the mic preamplifier. Care is needed, so you do not cause problems!
Mic gain modification
(Pix 1) Locate the un-used solder pads
3814_ic-2200h_1-Locate_pads.jpg

(Pix 2) Apply some solder to these two pads
3814_ic-2200h_2-Tin_the_pads.jpg

(Pix 3) Add the 82 K resistor as shown
3814_ic-2200h_3-Add_new_res.jpg

Reassemble the radio. This modification will result in a pleasing increase in sensitivity of the microphone. The ratio resulting as from the newly added resistor will provide an increase of the microphone preamplifier's audio level.
 

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