Different plane, same fix

No, I suppose not. Long day (I know, no excuse).

Well ... I was going to say that it didn't sound like you ;-)
Let's forget it.

Besides -- maybe I *like* a short to ground -- d'ja ever think of
THAT?

:-)

Follow up: Although the whine is better now, after tightening the
screw, it's still there in the background.

Gotta keep looking, I guess.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

On Jun 20, 11:54 am, Jay Honeck wrote:
When we flew our '75 Warrior, it developed a problem with the
alternator going off-line in flight. This was preceeded by the
ammeter needle bouncing crazily and finally pegging at 60 amps.

I fixed that problem by spending an hour tracing all the electrical
lines, and tightening connections. The main culprit was a wire
connector that was screwed into the backside of the alternator with a
simple phillips screw -- no safety wire, no loc-tite, no nuthin'.
Looked like a ground wire to me, but I'm no mechanic.

I turned it a good two and half turns, and the problem went away,
never to return. We sold the plane in '02.

Recently, Atlas developed a nasty, annoying whine in the headphones.
This developed immediately after I had removed the PS Engineering CD/
Intercom for some panel maintenance, so I naturally assumed that they
were related.

No amount of re-seating, cleaning, wiggling had any effect. My
frustration was mounting.

Then, this past Sunday, I decided to chang the oil after our return
flight from the Cherokee Pilots Association fly-in. It was Fathers
Day, it was 100 degrees in the hangar, and we were both melting, but I
decided to de-cowl the plane in order to make the oil change easier,
and to trace the wiring -- just in case it was another loose
connection somewhere.

Of course, the first place I looked was the backside of the
alternator, and, lo and behold, the same damned wire was loose! A
few turns to tighten, and voila! -- no more whine. (I traced the rest
of the wiring, while I was at it, and found a couple of broken zip
ties, and one broken wire -- a lead going to one of my cylinder
heaters. It's broken right where it goes into the cylinder -- THAT
looks like absolutely no fun to repair...)

Anyway, what should I put on this stupid screw to stop it from
vibrating loose? LocTite? Another lock washer? There's no way to
safety wire it...

Thanks!
--
Jay Honeck
Iowa City, IA
Pathfinder N56993www.AlexisParkInn.com
"Your Aviation Destination

The wiring diagram shows a three wire set up. Field, Batt. and
Ground. Field and Battery or A+ are going to be studs with nuts.
Your screw into the case is apparently the ground connection for the
alternator and a good choice for a noise in the headsets complaint.
The noise could still be a bad diode but a poor ground would only
exacerbate it. A good quality lock washer under the head of the screw
is essential shop practice in this case. There are different grades
of lock tite including removeable (go figure). You want to avoid
getting lock tite on the mating surfaces of the screw, washers and
terminal ends to avoid inadvertently insulating them.

John Dupre'