Bruce Hawkins
AC6DN.
08-05-2004
FT-100d, Mic mod.
Rev. 5
 

• This mod is for poor sounding audio, (If ur slightly, "Carbon mic", buzzy, raspy, or crunchy, sounding (especially if ur, a close& or loud talker, too much hi's).
• First check that mic levels in the menu are set correctly, I seemed to need, 25-35 for FM Mic gain, 25-40 for Mic gain (which only works when NOT using the COMPressor!), and COMP Gain at 25-35, for Q-5 (good) conditions and 35-75 for Q-3 through Q-1 (poor), conditions!  Local (1-2 miles) HAM's say, I sound, a little raspy, above 50, but those who are having difficulties hearing me, vary much, prefer 60-75, they clam Q-2 becomes Q-4) for SSB.
• Check to see if DSP MIC value of something other than 1 is turned on;  I.e., 1, is ok, or off.
• I assume that u are a technical type, that can do mod's, and repairs, can handle simple hand tools, and a Drimmel or drill (and have them);
• If not don't do this mic modification!
• Use at ur own (or ur radios) risk
• Observe ESD precautions, there is active comments (IC's, & Trans., etc.) inside.
• Save all extra pieces! Your voice may be different than myn,
 
1) Remove 3 Philip screws on the back of the outside mic case,
2) Carefully lift, back of mic, off,
3) Unplug, white, mic cord connector, don't pull wires,
4) Remove pcb screws (3 Philip). Remove, vary small philip screw that holds ptt switch (on pcb. 1),
5) Lift pcb out of mic case,
6) Carefully remove mic (elect. condenser) element, form mic case, NOT by the wires,
7) Remove rubber piece,
8) Remove small plastic baffle,
9) Carefully drill out, the un passed through hole, or enlarge existing holes vary slightly (this is what I did.
10) Carefully drill in to the side of the round piece that holds the mic element, on the side facing the ptt switch. (the idea is to allow breath noises to pass though the mic holes and out, instead of rattling the electro-condencer mic element. This resulted in the most improvement.
11) Clear Debree, deber holes,
12  Remove black felt covering the mic element,
13) Add cotton between the mic case and the rubber piece that hold the mic element in the mic,
14) Add rubber piece to mic, then install them back into the hole with baffle (or not?),
15) Put it back together; Do items, 5-1, Check for debree on pcb traces or rubber key pad, before reassemble,
16) Do an 'on the are test', may need different menu mic settings,
17) If too much breath noises, re-dissemble, either, add more cotton between mic element and case, loosely; Or reinstall baffle; Or both (I presently have the baffle installed, and cotton)...
18) Start with, mic/comp gain, of 25-35.

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