"Bad" CAI302 Display

Dan Marotta wrote, On 9/17/2013 8:42 AM:
Well, calling Gary *would* be the elegant solution but I thought he
wasn't working on CAI instruments any more. I can call...

As to simply rotating the glass - that was my initial thought so I asked
Paul at Cumulus Soaring. He thought the problem was with the actual LCD
and not the front glass. So I started thinking about it... Having no
direct knowledge of LCD construction other than at the highest level, I
believe there's a back layer which contains the electronics, a layer of
the liquid crystal, probably a transparent layer in front of that with
whatever circuitry is necessary to complete the electric fields to
change the state of the crystal, and a front layer, which may be
polarized. There may be other layers which I don't think matter to this
discussion.

If it's the front layer of the sandwich, then it was incorrectly applied
during manufacture and there's no fixing it. If, on the other hand, my
imaginings are wrong and it *is* the front glass, then that should be
easily rotated. Then the only problem is the possible violation of the
electronic seal.

I don't think it's the front glass, as I can see the needle clearly
through my polarized glasses, but not the LCD.

The 302 isn't my only problem, but also the Butterfly display for
PowerFlarm, and the ClearNav display to some extent. The Becker
transponder display and the MGL radio display are not affected,
regardless of the sunglasses orientation, so they must use a different
kind of LCD.

I've dealt with the problem by punching holes in the polarized clip-ons
that I use with my prescription glasses. The holes are located low on
the clip-ons so I can see the panel while I'm looking outside. The
oblong holes are about 0.3" high and 0.4" long. Besides solving the LCD
problem, the lack of tinting makes it easier to read the instruments and
flight computer in any lighting, but especially dim light.

And, yes, I do look a little strange when wandering around the airport
with holes in my sunglasses, but it's a small price to pay for being
able to see!

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm
http://tinyurl.com/yb3xywl