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Circuit breaker tripping on SV-ADSB-472

JohnTEEX

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I have dual screen SkyView Classic in my RV-9A. It was installed 4 years ago and has worked flawlessly until now. I added a Garmin GPS-175 about three years ago, and it also has worked flawlessly for the ~175 hours since then.

A few weeks ago, I noticed that the system reported "ADSB-IN OFFLINE" and that a 1A circuit breaker in my aircraft had popped. I reset the breaker and the ADSB-IN (SV-ADSB-472) came back online. All other systems continued to work properly. On another flight a few days later I got a similar message and this time apparently the 1A breaker had failed (resetting the breaker did nothing, and a continuity check on the ground confirmed this). Since then, until yesterday, I had flown without ADSB-IN and the 1A circuit breaker, and the rest of the SkyView components continued to function properly. ADBS-OUT continued to function properly (it's on my transponder circuit).

Yesterday I replaced the failed 1A with a new 3A breaker and it functioned fine for most of a 25-minute flight. Near the end of the flight I saw the new breaker pop and again received a warning ADSB-IN OFFLINE. Something else seems to be at play here. I’ve checked for any shorts at the wiring to/from the circuit breaker and have found none.

Aside from a thorough, painstaking connection-by-connection examination is there anything in particular that a likely source of the tripping? Is it possible that the SV-ADSB-472 component is failing (although it worked fine initially when the new breaker was installed)?

Insight welcome!
 
You have a short to ground somewhere - either in the unit itself or in the wiring leading to it. The ADSB-472 normally draws only 0.1 amp of power on a 12-volt system.

Alternatively, you could have two bad circuit breakers in a row - but that's much less likely.
 
I would suggest returning the 472 back to Dynon. Warranty or not, I have found their customer service to be excellent. If out of warranty, they have a very reasonable flat rate repair cost (vs. Garmin).
 
Another option would be temporarily running another wire from the circuit breaker to the connector on the Dynon. Remove the original wires from the CB and the -472 connector and run the new temporary wire along a different route. If the breaker doesn't pop, it is something in the old wiring. If the breaker does pop it is the -472.

Or ask Dynon to swap out the unit, as others have suggested.

:D
 
Another option is to install a 1 amp fuse right at the SV-ADSB-472.
If the fuse blows, the problem is internal to the SV-ADSB-472.
If the fuse does not blow, the problem is external to the SV-ADSB-472.
 
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