This is what I wound up with at the end of yesterday:
It might look like a mess, but it’s not. Every pin in every connector has been checked twice, and the coils are grouped by device and function. Except the one or two I missed. This has been an exercise in patience and squinting at little wires. It’s like everything else in this project: If you look at the whole thing it looks insane and impossible, but if you look at it one piece at a time, it’s not that big a deal.
Each wire only has two ends, so that makes a good place to start. First I did all the power and ground connections. There are several. The 430 has 3 devices in one, but only two have their own power feeds, unless I’m driving a superflag device off the NAV unit, which I’m not. The audio panel is the hairiest part, because there are so many connections and a couple of them share pins, which sucks, because you have to make pigtails that combine two wires, usually audio returns, into a single pin that plugs into the connector. The shields absolutely suck. I probably should have used 24ga wire, but I had green 20ga wire, so I used that. That’s where I learned the Aeroelectric (and probably standard) way to bridge shield to a standard wire. That wasn’t that difficult, but there were a lot of them, and now they’re all ganged together and fastened to the audio panel’s frame. The deal is, you ground the shields at the audio panel to reduce noise, or at least attempt to do so. Supposedly this is how you keep EMI noise out of your audio connections, which tend to run all over the aircraft and often past some noisy things like strobes, relays, etc. Now, hopefully, in crushing together all those cables, I haven’t compromised the insulation integrity, and during the soldering process, didn’t melt through any signal wires. I still need to verify connectivity and isolation, but I’m off to Vancouver for SIGGRAPH, so that’ll have to wait.
I couldn’t just leave it be, though. I powered up the audio panel, which lights up fine, but I didn’t want to risk powering up the radio. If something is screwed up in my wiring and the mic key is stuck on, the RF power with no antenna will fry me out of $7500 worth of radio, GPS, and NAV equipment. Not to say I didn’t try. I had some leftover RG400, which I put a BNC end on, and was going to connect the other end to my COMM antenna, but that didn’t happen. RG400 cable has two layers of shield on it, so the usual trick of pushing the shield down and pulling the wire through doesn’t work. My current RAMI antenna needs pigtails for wiring, and dammit, so does the marker beacon antenna. So I need a COMM antenna that uses a BNC connector like everything else.
One thing I missed while I was wiring is the COMM remote recall function. This uses a discrete input (fancy name for an external button) to scroll through a list of preset frequencies. It looks almost useful enough to take apart the main connector on the GNS430W and add a tail for it, but I don’t actually have a free button for it. If I didn’t do remote ident on the transponder I could. The other suck part about the GNS430W is that it doesn’t have the same remote function protocol as the SL30, which can be fully controlled via RS232 communication. Sure would be nice to be able to set frequencies from the EFIS, but this setup will be fine as is.
I also got a phone extension cable to make up for the shortcomings of the one shipped with the ACK 406 ELT, which doesn’t quite reach all the way to the panel after threading its way through the wire bundle. I also figured out how to install phone cable ends, a skill useless in every other facet of life, since I don’t even have a landline anymore and subsequently will probably never wire a phone jack in this house. The new cable, with the end cut off, goes fine through the portholes I drilled for the strobe cable. Yes, I know it’s probably bad, but as long as the strobe noise doesn’t trigger the ELT’s emergency transmit mode, I can live with it.
When I get back, I’ll also have to dismount the EFIS to install the ELT remote switch and verify GPS communication. Then my time in the tailcone is DONE. I’ll reinstall the flap arm and the flap motor and call it a day.
The other thing I have to do is run another wire for push-to-talk on the pilot side. The audio panel has facilities for multiple push-to-talk sources, diagrammed by shorting the PTT circuit to the MIC return, which is the same thing as shorting it to ground. Right now, I have both PTT buttons coming out of one wire, and I need two, one for pilot, one for copilot.
I also need to lay out my wire codes on here so I have a record of them.