I recently had a problem at not transmitting; no sidetone. however I was
putting out a carrier. I corrected all the obvious problems that have
been mentioned and there were a couple of the finger contacts in the
tray not correct. But, in the end I returned it to Narco. They found
several problems one of which would relate to my problem of no sidetone
and no transmission. I got it back in fine condition for that problem. I
did develop another problem that the audio will not always break squelch
even when the volume knob is pulled out. I can 'solve' the problem by
turning up the volume until I hear the background sound (the audio pops
back as normal) and then turn it down and push it back in. The audio may
work the rest of the flight. I was in the habit of every few minutes of
pulling out the volumn knob to be sure it is still working. I do not
want to miss an ATC call. I contacted Narco and they will fix it under
my repair warranty. Otherwise, both of my MK12Ds have been good. The
other radio is needing a new display and may be sent to them during the
next annual and when I am satisfied that this radio is working.

Oh, to have the money to redo everything with new.


Regards, Ross
C-172F 180HP
KSWI


three-eight-hotel wrote:
Arrgghhhhhh!!! :-(

I took a 45 minute flight to Willows this morning, for breakfast...
The radio worked like a charm all the way there... I took off out of
Willows, and 5 minutes into the flight (while monitoring Oakland
Center), I noticed the reception was getting scratchy, then... No
transmit, no reception, no side-tone while attempting to transmit. I
tried applying pressure to the radio to make sure it was seated
properly and even tried wiggling it a bit while applying pressure,
but... nothing!

However, about 5 miles out from Cameron Park airport the radio worked
for about a minute and enabled me to make a down-wind call. Then...
the same thing, no transmit, no receive, no side-tone while
transmitting! :-(

I think I confirmed (once on the ground at Cameron Park) that I can
plug my headset into the plane jacks and by-pass the intercomm, so
that's what I will try next, as well as throwing in a TKM that my
mechanic says I can try...

It sure seems like a vibration or heat issue??? Once on the ground and
the plane shut-down and secured, I plugged the headsets back in to the
intercomm and the radio worked like a charm. That would confirm the
several hour bench check done by the avionics shop. Something is
happening in flight... Any thoughts?

I couldn't get anything off my intercomm to provide a make/model. I
had my friend take a digital pic of the panel, so I should be getting
that soon, if that will help???

Todd