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Transponder acting up

Posted: Thu Jul 05, 2012 12:50 am
by Victor
Wondering if anyone has seen this. Transponder would not stay ON or GND/ALT for more than 3 seconds and would go back to STBY by itself. After that Alerts window shows "XPDR1 SRVC – XPDR1 needs service.
Return unit for repair."
After a while message goes away. After power cycle everything back to normal until GND or ALT is pressed.

Re: Transponder acting up

Posted: Thu Jul 05, 2012 4:13 am
by Lance Murray
You can try re-racking the transponder. Other than that I think you need a trip to the shop.

Re: Transponder acting up

Posted: Thu Jul 05, 2012 6:52 am
by Antoine
It did happen to me - only once, and then the message disappeared and never showed up again. I would support Lance's suggestion: I have already had 2 cases of "failures" which turned out to be a mere bad connection.

Please let us know how it goes as this could be very helpful to others. Avionics issues can be real headaches...

Re: Transponder acting up

Posted: Thu Jul 05, 2012 6:54 am
by Victor
Tried re-racking first. Same result. Any diagnostic info anywhere to look at. anything gets logged ?

Re: Transponder acting up

Posted: Thu Jul 05, 2012 11:19 am
by Antoine
I think the G1000's error logging and diagnostics functions are only accessible to an avionics specialist.

Re: Transponder acting up

Posted: Thu Jul 05, 2012 11:44 am
by Jean
Victor,
I've had the same problem during an IFR flight last year, but without the error message. I noticed that the transponder code wasn't green (active) on my pfd, so tried several times to encode it again, to recycle but it didn't work. ATC warned me they could'nt identify me anymore . I pulled the CB off and than on again to reset the transponder and it worked normally afterwards. Never happened again since.

Re: Transponder acting up

Posted: Thu Jul 05, 2012 5:32 pm
by Moonshine
I have disappeared from the radar once or twice on one flight, recycled the CB and it helped. But that was in a fairly heavy precip and my COMM1 was acting up too - so I just replaced all the waterproofing around antennaes and it seamed to help. On that flight old dry caulk was just washed away letting the water get into the connectors.

Re: Transponder acting up

Posted: Thu Jul 05, 2012 10:47 pm
by Victor
After a conversation with Garmin field support the unit is going for replacement ($700). They told me it has happened in the past and they are not sure what causes it to happen. Will report once I get the replacement next week.

Re: Transponder acting up

Posted: Fri Jul 06, 2012 3:31 pm
by Eric N
About 1 1/2 yrs ago at annual the transponder antenna was discovered to be failed: evidently the plastic housing had cracked and allowed water, etc inside. The surprise benefit was that I now almost never get "Mode C lost--recycle your transponder" from ATC, which was not uncommon before. I had always assumed that radar coverage was spotty as the cause, but evidently not. There was never any system error message, though, so this is likely not what's bothering you.

Re: Transponder acting up

Posted: Fri Jul 13, 2012 11:56 pm
by smoss
Victor, my transponder did the EXACT SAME THING 2 months ago or so (about 650 hours TT). Reracking did nothing, and all configuration stuff was confirmed correct, but still gave the error and didn't work. I did the $700 exchange and has been cured ever since. Of note, when first installed it gave a software mismatch error as the new one was loaded with a newer software version than my origninal transponder and transponder driver equivalent, and would not work. The avionics guy had to go back to his shop, download the new transponder software from garmin for the plane onto an SD card, and install the new transponder software into the plane in, and THEN it worked. Be prepared for him to have to do that.