Microair T2000 Transponder Issue

Hey folks

I have a Microair T2000 transponder in my -8. I sent it in for update years ago when the firmware in it locked up in Mode-S radar areas. It seemed to work fine afterwards. However, I have had an intermittent problem ever since, and it recently reared its ugly head again on a trip to escort the RV-1 from Maine to New Brunswick.

A number of times either Terminal or Center would say they had lost my transponder and would I cycle it. I would cycle it and it would normally come back, although once it didn't until I got to the next Center.

I have checked the connections on the back (power, encoder, antenna) and all seems good. The display always shows the correct pressure altitude and assigned code.

Any ideas why I would have to cycle it periodically ? I have made trips where it has performed flawlessly, but other trips have been like this. Frustrating, and a little unnerving, especially when you are crossing the border into the US. They have A/A missiles 'n stuff

Anyway, if you have a suggestion, please let me know.

Cheers

My experience

This may not help you, but I had the same issue with my KT76A - intermittent Mode C, sometimes fixed by re-cycling the Mode C. Since it was on a certificated A/C, I could not troubleshoot the problem. The radio shop found an in-line connector (in a 4' cable!) that had an intermittent internal short. Only .5 AMU later, and I had a new cable and no more Mode C issues.

Sam Staton

Hmmmm... interesting. I have a 90 adaptor at the antenna end. I wonder if that might be it.

Thanks, Sam. I'll look at that adaptor a little more closely.

Same here

rv8bldr said:

I have checked the connections on the back (power, encoder, antenna) and all seems good. The display always shows the correct pressure altitude and assigned code.

Click to expand...

Hi Mark,

Mine did the same thing, but had no power output what-so-ever. I bought a "new" unit that was "installed but never flown" several years ago at a regional EAA Fly-In. When I had Walt from EXP Aircraft come by and do the initial transponder check, it was a no-go as far as output, but displayed everything just fine.

Several $$$ later, I have a Trig transponder installed and it works perfectly. Search MicroAir on this forum alone and you'll find few praises. Good luck going forward.....

Me too

I have the exact same problem with my Microair transponder. It usually comes back when I cycle it. I have noticed the problem almost always is associated with cold damp weather and my failure to plug in my cockpit pancake heater after the last time I flew.

not familiar with this exact brand but previous experience with other brands I have seen, this sounds like your xmit freq may be off. I have seen 90 deg adapters do this. Some atc centers are more sensitive to this than others. I would try without the adapter is possible but the best course of action would be to have an avionics shop put the tester on it installed in the a/c.

Let me just say that I wouldn't spend too much ("too much" is relevant number, but to me, that would mean anythng) trying to fix it

Thanks for the responses, guys. I'm going to try ditching the 90 deg adapter first (that may involve making a new antenna cable, darn it!).

If that doesn't fix it, well, ..... $$$