In spite of the fact that the EFIS is still in the shop, I was able to produce actual panel work today. Today was the cleanup of the rat’s nest behind the subpanel. I bundled the wires, organized the loose ends, and finally permanently wired the pilot PTT wire. Not only that, I ran and wired the copilot headset and mic, and connected the remote ident wire for the transponder, and it works on both stick grips. A good day.
I picked up another LED and microswitch, with the intention of actually wiring up EFIS power to the switch so I can power cycle it in flight if necessary. Not doing so initially was stupid on my part, but since the thing is in the shop, it’s not that big a deal. The LED is for the alternator warning circuit. Supposedly if the alternator goes funny, it sends 12v to something to let you know.
I didn’t get a chance to wire the ELT GPS power, that’ll have to wait for another day, but it’s a gimme. Should take no time at all. I have exactly two terminals left, and they’re both spoken for, so I want to have the EFIS back in so I can get the wire length right before I crimp a terminal on there.
Of course, without the EFIS howling into the radio spectrum, I can hear SMO ATIS, which is kind of neat. Hopefully this week I can complete the leftover tasks, because a week from today, I go up to Seattle for two weeks for work.
This is actually from last sunday, but this is the first chance I’ve had to actually write it down. Happy Thanksgiving, everyone. I give thanks for… The fact that MGL Avionics is being unbelievably awesome about fixing my EFIS. Again.
I finished the connections for the SP2 and SP4, wired everything up, and started cleaning up the mess behind the EFIS. I got everything wired in and properly arranged and the whole thing went south in a big hurry.
Over the last couple of weeks, I noticed a bit of flickering across the EFIS display, and sometimes the unit would crash, with the White Screen of Death. This is usually solved by power-cycling the unit. Not today. Today the WSOD came on and stayed on. So rather than a complete and utter freakout, I just resigned myself to sending the EFIS back to MGL for any necessary repairs. There’s still plenty to do.
Ran the twisted triple up the centerline for the AHRS and compass, made a new harness to connect them, and finished the harness for the AV2 backup instrument. The antenna inside the shop still dumps RF into the EFIS with the sensors connected, which is bad. I think it’s largely due to bounced energy off the metal stuff in the shop. Still, this solution is less wire, and therefore less weight. It also combines the AV2 sensor input with the Odyssey sensor input with no need for a Y-adapter, which has no place in an aircraft.
But at the end of the day I was utterly foiled. I don’t have a screwdriver long and thin enough to reach through the access holes to unscrew the DB9 connector on the back of the compass. So that’s going to have to wait.
Adding this from last weekend. Got everything back in, with ferrite beads installed on everything going into and out of the EFIS and the GNS430w. There’s definitely a big difference in both the amount of noise generated by the EFIS and the amount of RF dumped into the EFIS on transmit, even in a shop full of metal things. I still have to wire in the RDAC and sensors permanently, but this time around, I actually got the EFIS audio output wired in correctly, and I can now hear Bitching Betty in my headset. The volume is a little low, and the sample rate is terrible. I’m not sure what to do about that. Maybe Matt at MGLUSA can shed some light on it.
I also mounted an avionics ground plate full of tabs right near the radio stack for shorter connections between avionics and ground. It also looks like my antenna will go under the pax floor pan to keep it as far away from the antennas, sensors, and servo in the tail or the radio stack and EFIS.
I also get to fish out the cheesy RCA cable from the main bundle and replace it with a twisted triple to carry power, ground and data to the AHRS and magnetometer. If I can get all this shite to sing in harmony, then it’s on to the baffles and other FWF fun.
The system won’t be noise-free until I no longer have unterminated wires, which means at the airport with the wings attached and all circuits complete, but I can live with that for now.