Mark 12D Problem???

Sorry... Forgot to respond to other question...

I have:
1) a stand-alone Mark 122 NAV with glideslope (not part of the radio
system)
2) ADF (Inoperable - receives but indicator is off)
3) four place intercom (generic - nothing fancy)
4) standard mode-C transponder (also not part of the radio system)

Pretty basic... Love to throw in a GNS 4 or 5 -30, but that's a
pipe-dream for now... (Single income/two kids :-)

Thanks again!

I really prefer to troubleshoot, but the implication in your posts is that
you aren't "into" technician level electronics. If I've mischaracterized
you, I'll go at it from another route.

First, get yourself a can of tuner/control cleaner (Radio Shack 64-4315).
Do NOT use generic WD-40 or other petroleum based cleaner. You don't want
to leave a greasy residue AND you don't want to cob up the high frequency
characteristics of the connector(s). Mark 12D ... let me recollect ...
there are three or four versions of connector used on the 12D. Most
probably, since you have some sort of Cessna audio panel you have the
12D/Cessna version with the square block "Winchester" style connector.

It doesn't really matter. Use a very small amount of the cleaner on both
the radio connector and the tray connector. While the cleaner is still wet,
insert, pull, reinsert, pull, reinsert the radio half a dozen times.

Report results.

BTW, what model audio panel and model intercom do you have?

Jim



"three-eight-hotel" wrote in message
oups.com...
Sorry... Forgot to respond to other question...

I have:
1) a stand-alone Mark 122 NAV with glideslope (not part of the radio
system)
2) ADF (Inoperable - receives but indicator is off)
3) four place intercom (generic - nothing fancy)
4) standard mode-C transponder (also not part of the radio system)

Pretty basic... Love to throw in a GNS 4 or 5 -30, but that's a
pipe-dream for now... (Single income/two kids :-)

Thanks again!

You have not mischaracterized me... ;-)

I beleive you are probably on to something with the connection
diagnosis... Vibration would be a great explanation to the 30 minutes
of working, then failure. I thought heat might have had something to
do with it to, but sometimes it fails at first attempt of using it.

I will try your suggestion and report back... (It may be a day or two)


I will also report back on models of audio panel and intercom I have.
(The second image in the link I sent "Figure 7-11 Used with Three
Transmitters" looks exactly like my audio panel, if it helps) The
intercom doesn't have anything indicative of a model on it, so I'll
have to poke around.

Thanks again and I'll report back soon!
Todd

Jim,

I bought the tuner/control cleaner yesterday and stopped at the airport
on my way into work this morning and did as you suggested... I sprayed
cleaner on the radio connector and tray connector and slid it in and
out half a dozen times. I then locked the radio into place (It seems
as though I got a better lock this time than I have in the past, as the
locking mechanism didn't seem to fall into place as well in the past)
I made a local "radio check" call and got a quick response of loud and
clear!

I won't be able to get out and fly it until probably Friday morning,
but will post back with the results. I just wanted to send a quick
update and let you know that I've got a good feeling about this!
Thanks for your help!

BTW - I checked out your website... Very nice! Looks like a lot of
cool products! I live in Garden Valley, near the Georgetown airport so
we are practically neighbors...

Back soon with results from the test flight...

Best Regards,
Todd

You have just made your first unauthorized aircraft repair. CONGRATULATIONS
and welcome to the sororfraternity.

{;-)

Jim



Back soon with results from the test flight...

Best Regards,
Todd

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

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

yeah... I keep thinking (man, if I just had 10 or 15k laying around,
how I could make some nice improvements). I do like the MK12D
though... It's a nice looking radio and worked very well until this
bout of issues I've been recently having.

I just wish I could isolate the problem directly to the radio! I think
we are going to throw it in one more airplane and put that TKM in mine
and see what plays out...

Thanks for your response!

Best Regards,
Todd