Ovation 2 - G1000 : COM II and AP + trim - TU on start-up

[N177MC]

So out of the blue (last flight was uneventful no problems w the avionics) , on start-up, the COM II, AP, elec. trim and DME are all flagged inop, see photo.

Checked all the obvious things, breaker, E Bus, etc., etc. , nothing anormal found.

I'm thinking it may have something to do with the Emergency Bus,  since switching the E-Bus takes both the COM II and the AP & trim offline.

Any ideas where the E-bus relay is mounted ? 

 

[LANCECASPER]

This sounds obvious, but since the Emergency Bus switch is right below the Master Switch, could you have hit that one by accident?

[GeeBee]

Both the #2 GIA and the A/P are on the non-essential bus. I would try resetting the MFD C/B and see what it does. Both those units report in through the MFD.

[MatthiasArnold]

I like GeeBee‘s proposal. Communication via GIA2 and with GIA2 itself seems to be broken  
AFAIK as long as you don’t pull the battery CB, all systems are powered ..

[GeeBee]

I've also seen a few GIA's get "cranky" when it is cold. Don't know what your temps are there (likely cold) you might blow a little heat in the E&E and see what happens.

[N177MC]

Thanks guys for the ideas. 

Just to be sure, I did cycle the E-buss switch multiple times and noted no change, which kinda leads me to believe that it might be related to the e-bay switching / relay.

I got a PM (thanks Deb!)  suggesting that if the GIA63 II goes off-line that it will drag down a bunch of of other appliances with it, so will defiantly have a look at the GIA.

 

Any other ideas welcomed !

[N177MC]

Follow up : Turns out that the GIA63 2 LRU  needed to be de-racked, connectors cleaned and Voila, problem gone !

I suppose that since these LRUs live in the rear fuselage are more prone to cold & humidity .

Thanks for the assist !

[BlueDun]

I had a similar problem with my GIA63w 1 LRU. Host of problems. We  cleaned all connections and re-racked. Just picked it up and have had no problems for 10 hours.