Of clocks and learning curves...

So I picked up this nifty Davtron digital electric clock/timer at Sun N Fun.
It's exactly the same model I had in my Warrior (Model 800), and I found a
good price for it. (Roughly 4 times what it's really worth -- a bargain in
aviation!) Our wind-up clock had become sporadic in cold weather, and I
kept forgetting to wind it anyway...

My A&P took one look at the box and said "This will be a snap to install!"
This should have set off warning alarms right away, but it didn't. We
decided to do it at the annual, when everything was already ripped apart
anyway.

So, after most of the annual was complete, Darryl (the junior A&P in our
2-man shop) dug into it. As expected, it turned out to be a real
son-of-a-bitch getting at the backside of the panel. I ended up standing on
my head under the panel, holding the clock in place with the very tips of my
fingers, while Darryl carefully dropped the tiny little retaining screws
onto my belly, over and over again. It was fun! Really!

Eventually, through sheer persistence, he got the damned screws threaded in.
Then the real fun began -- wiring! The directions clearly called for the
dimmer control wire to be connected to one of the panel lights, and the hot
lead to go directly to the battery. Unfortunately the battery was in the
way back of the plane -- not exactly handy -- so Darryl decided to wire it
into the hot side of the master switch.

This made sense to me -- which, again, should have set off warning bells in
my head, but didn't -- as the master switch was a heckuva lot closer than
the battery.

So I picked the plane up today, after reassembling the last little bits and
pieces. Everything looked great, the engine fired up easily, I taxied about
40 yards -- and the clock blinked out and died....

Immediately spinning the plane around, I shut the engine and master down --
and the clock came back to life! So, I turned the master switch back on,
and *poof* -- 15 seconds later, the clock went blank.

What the hell!?

Darryl was completely stumped, and a huddle of wise old airport bums
immediately assembled. It was obvious that hooking up to the "hot" side of
the master switch was NOT giving us continuous power -- but why?

No one knew, and I had to get back to the hotel. I took the plane back to
my hangar, and left the wise men standing there scratching their heads.

As soon as I got back to the inn, I called Davtron. Describing the symptoms
to them, they immediately knew the problem. Apparently the Piper master
switch -- on the hot side only -- "powers down" after 15 seconds! Some
solenoid somewhere gets thrown, grounding the circuit and killing power to
the hot side of the master switch.

They said I had two choices: 1) Run the power directly to the battery,
clear in the back of the plane, or 2) send the clock into Davtron, for free
installation of a battery back up. This battery allows the clock to be
connected to the avionics master, rather than a "hot" wire.

I immediately called Darryl, and gave him the options. He has agreed to
fix the problem on Monday, whatever it takes, free of charge. Rather than
take the thing out, send it to California, and reinstall it -- he's opted to
run the wire to the battery...

Live and learn -- who'd ever think that installing a gol-danged CLOCK would
be so hard?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"