I have just re-read your post and you say your K20 doesn't recognise the A position. Mine does, so I suspect it may be a little more serious.

I wouldn't think it to be a viable option to get it repaired, probably cost more than its worth.

I would have a go at it myself if you are mechanically minded.

Heres an exploded view of the lens. If you want the full sized version, PM me your e-mail address and I will send it to you.

[IMG]http://i184.photobucket.com/albums/x261/ClarkyinAus/50mmlensillustration.jpg[/IMG]

You can see the pin here which locks it into the A position.
[IMG]http://i184.photobucket.com/albums/x261/ClarkyinAus/50mmA17.jpg[/IMG]

Yep the rubber cup rotates, so it can be used for either eye.

It sure does, I love mine and use it more than my K20 at the moment.

My 50mmA 1.7 does the same thing. I believe it was forced at some time and the locking pin broken off inside.
Does it rattle when you shake it:

Unfortunately the 50mm A 1.7 does have a history of aperture ring problems

Doesn't particulaly bother me though.

I have never heard of bubbles forming in the glass or ever seen it.
How big is the bubble and how is it possible for a bubble to form inside the glass:

I picked up four of these with a bunch of Takumar gear I recently purchased on E-bay.

I use one on my DS for macro photography and much prefer them to the Pentax eyecups

If you want one and can't source it over there for a descent price, I will send you one of these for the cost of postage.

The round one is an olympus eyecup and it has a glass in it and I suspect is magnified slightly as I had to adjust my diopter after installing it, or it could be just that your eye is further from the view finder, but thoroughly recommend one for macro.

They both fit my K20 perfectly and in excellent condition.

[IMG]http://i184.photobucket.com/albums/x261/ClarkyinAus/IMGP9194.jpg[/IMG]

[IMG]http://i184.photobucket.com/albums/x261/ClarkyinAus/IMGP9195.jpg[/IMG]

I have yet to have one fail, all 8 of mine are sandisk, a mixture of extreme III, extreme II and ultra.

Welcome back Peter I hope all is well.

Love that shot, especially the colours of the sky.

I have seen his work before, awesome stuff I had a brief chat with him mid last year and he sent me a pic of his camera setup. He shoots with an ist* DS with a reversed 50mm lens on bellows and a home made flash setup held together with gaffa tape.

Goes to proove its not what you got, but how you use it.