Radio sidetone problem

Hey again.

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.

Thanks in advance.
Marty

Marty from Florida wrote:

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.

I had a NARCO Mk-12D and a Quiet-Flite intercom in my aircraft. I found that the
sidetone was controlled by the intercom. If I wanted more sidetone, I had to
turn the intercom volume up (and turn the radio volume down to keep what's left
of my eardrums).

George Patterson
Whosoever bloweth not his own horn, the same shall remain unblown.

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


--

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

Join the Cessna Pilots association (www.cessna.org)(I think it's $39.00/yr)
and ask them. Tom Rogers, their avionics guy, is really experienced and
knowlegeable.

DB
"Marty from Florida" marty@-x-x-x- remove -x-x- worth.net wrote in message
.. .
Hey again.

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.

Thanks in advance.
Marty

Thanks for the replies. I recently read that my panel mounted intercom,
(David Clark Isocom), also has a sidetone function. I wonder if the sidetone
in the radio (TKM-MX385), is conflicting with the intercom's sidetone?

Just a thought. I'd like to have a quick, easy fix, but it's looking more
complex than I'm comfortable messing with. Do these Nav/Com's have an input
for a PTT cable? Where should my yoke mounted PTT wire go, the intercom or
the radio?

Marty


"Marty from Florida" marty@-x-x-x- remove -x-x- worth.net wrote in message
.. .
Hey again.

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.

Thanks in advance.
Marty