I flew the airplane today, and headset noise (alternator whine) has not
been completely eliminated by the resolution of the ground loop through
the intercom system, but it has been further reduced to a level where it
is just manageable. The "chop chop" or "flutter" electrical noise is
still occasionally present in the system when the copilot transmits, and
can be heard in the sidetone.

HOWEVER, I've now discovered another potential problem. In my quest to
inspect ground connections, I pulled the cover on the rear bulkhead to
look at the glideslope receiver, strobe power pack, and battery. The
master relay is next to the battery, and I nearly burned myself on it
after a 30 minute flight--it was that hot. I let it cool down, and ran
the airplane for another 5 minutes and it was almost too hot to touch.

Logic tells me that heat is created by electrical resistance, and I'm
guessing that there shouldn't be enough resistance in the master relay
to cause it to get too hot to touch. Is this a failure mode for these
relays? Could this be contributing in any way to my electrical noise
issues?


Thanks,
JKG