Odd radio behavior

[Quint Van Deman]

Hello all--

One of my radios exhibited some rather odd symptoms the other day, I'm curious as to if anyone has any ideas or has seen the same.
The radio in question is an old TKM MX 12, it's certainly got some years on it, but to this point it's worked for me.
The other day, I tuned it to ground, and then the tower without issue.
At about 500 ft, I tuned it to departure, and hit the flip-flop button but got on response.
Not to be distracted I simply used the other radio, but once I had some altitude & time the problem continued to perplex me.
It would transmit on the active frequency, but every button on the entire faceplate had gone dead.
I cycled the power a couple of times to no avail. Frustrated, I left it alone and continued on the backup.
Later that day, on my return flight, after starting up, I noted the behavior was still there.
However, after takeoff, muscle memory kicked in and I tuned the problematic radio to the next frequency, hit the flip-flop and what do you know, it worked.
I gingerly tested it for the remainder of the flight and everything worked great. The only thing I can possibly think of is that I got one of the frequency tuning dials stuck halfway between clicks, which internally put the digital radio into an unknown state, and I knocked it out of that state when I changed the frequency later in the day (I don't think I tried changing frequencies in the interim).

Has anyone every seen or heard of anything like this? I'm going to chalk it up as cosmic randomness unless someone tells me to expect future demise of this radio!

Thanks,

-Quint

[Michael Bryant]

Not familiar with the TKM Mk12, but I have seen similar behavior with push buttons on other radios. If a button gets sticky and stays in the depressed position, it generally inhibits the push of any other button. I have sometimes solved this problems by pushing each push button until finding the guilty one. I let my mechanic know about it and some electrical contact cleaner often has helped.


Michael

[Quint Van Deman]

Thanks Michael, appreciate the confirmation.

Quint

[slaskey]

Quint,
I had a problem with my TKM Mk12. I would lose the audio output in flight, but have it the next flight. It turned out to be the couplers at the back of the radio and the jumper at the original Narco power supply coupler. The avionics shop tightened the connections last fall, and I haven't had the problem since.

Steven