Had an interesting event yesterday. Flew about a half hour to a local field (KAQO) that has (relatively) cheap Avgas. While there I ran into my old A&P/IA, who lives up there now. We were shooting the bull for a while about this and that, then he left and I started up to head back to home base. Only...
...couldn't get the ammeter to show any charge. Checked the circuit breakers, and cycled the ALT half of the Master several times, but no joy. Since it was day VFR and only 30 minutes from home, I elected to fly home on the battery. Used the ESS BUS switch for the first time (for real). I couldn't tell what load this was putting on the battery, but the battery voltage remained at 25.4 volts for the entire flight except when I lowered the flaps, when it momentarily dropped to 25.2 volts.
With dread of finding out that I might need a new alternator ($$) or voltage regulator (I have a spare), I uncowled and began troubleshooting. No loose connections on the alternator. No voltage to field terminal with Master and ALT on, so I'm happy that it isn't the alternator - looks like switch, wiring, or voltage regulator.
So, next the instrument panel cover came off, and lo and behold:
- Field wire off terminal on ALT side of Master
the wire to the field coil is disconnected. How the heck did that happen after 23 years. It is in the bowels of the instrument panel, so not likely to get inadvertently pulled on, plus, I've never been in that area for any work. The connector is undamaged, and held super firm when reinstalled:
- Reconnected
The only thing I can think of happening is that when it was installed at the factory, the spade lug went between the connector and the plastic insulator rather than into the connector. And there it sat, making contact for 23 years until it vibrated loose yesterday. At any rate, I'm happy I didn't have to spend any gas money to fix it, and I offer the experience just in case someone else has the same problem.
