Marty from Florida marty@-x-x-x- remove -x-x- worth.net wrote:
: I have a new TKM Nav/Com (Michel MX385) in a 1982 C152. The radio is great,
: clean, lots of volume. The sidetone, however, is very faint, almost a
: whisper, and it's making me nuts. On a rare occasion, while I'm
: transmitting, the whisper blasts out for a brief second, and returns to
: nearly imperceptible. The intercom is about 5 years old, but the box over
: the radio seems to be original (Nav 1/2 switch, sidetone VOL). It has a
: sidetone 'volume' button which rotates freely, and seems to be turning a Pot
: inside. Has anyone had this issue, and what is/was the resolve? I don't want
: to pay a shop 4 hours for an easy fix issue.

Although radios can be rigged to get their sidetone through the intercom, they
can generally be configured to produce it themselves as well. If you have another
radio and it doesn't exhibit that problem, it's most likely in the radio.

If it were just faint, I'd say it could be a sidetone adjustment pot out of
adjustment. My experience has been that volume levels are often *all over* the map
and lead to lots of noise, clipping, mismatching, etc. Since you say it comes in
blaring once in awhile, it sounds like there's a bad connection. It could be a
dusty/dirty/broken sidetone adjustment pot, or a bad solder joint somewhere that
affects the gain. Try pulling it out and see if there's a sidetone adjustment pot.
Note where it is, and try turning it back and forth a few times, putting it back where
it started. If it's just dirty, that might do it. Anything more, and it's probably
time to (have someone) open it up.

-Cory


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************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
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