Thank you for your answer. I only need the teleconverter function from this adapter in combo with a decent 300mm, i would manual focus to get the moon as sharp as it gets.

Best Regards

Here it is

1.7 AF adapter + 6x7 tele lens? - PentaxForums.com

Hello I would like to ask based on something you wrote 2011. I would like to combine
S-M-C/Super Takumar 300mm F4 Reviews - M42 Screwmount Telephoto Primes - Pentax Lens Reviews & Lens Database
with the 1.7 AF Adapter. With the Pentax M42 Adapter I cannot get infinity (which I would to have since i would shoot the Moon). You wrote that with a non infinity type Adapter I can get infinity in this situation? Which adapter should i buy or how thick should the Plate be.

Best regards Werner (and sorry for my bad english)

Sorry, did you get your lens diaphragm operational? I tried to respond when I saw your message back in December but I was interrupted by my wife's call for dinner, and I closed this message page but couldn't find it again after dinner.

It's been so long since I fixed the stuck diaphragm on my lens so I am not all that familiar with the disassembly of the lens but that can probably be found here in the forum or elsewhere on the net. Basically, after I had partially disassembled the lens (until the diaphragm became accessible), I literally drowned the diaphragm with naptha (lighter fluid) and working the diaphragm lever, while the blades were wet until the lighter fluid evapourated then repeat the process. I'd guess that I repeated the process at least 10-20 times and I have not had any problem with the diaphragm since then.

I hope this helps and again apologize for the late reply.

Thanks,

Hello
Back in September of 2010, you posted a problem with a CZJ 180/2.8 lens you had in which the aperture diaphragm was not working.
I read this posting and responses because I have the same lens that I inherited from my Dad, that has a similar problem. My particular lens has the M42 mount and is serial #8272906.
My issue is that the aperture ring rotates beautifully with very fine smooth clicking sounds, but the diaphragm blades are either stuck wide open at 2.8, or the ring has gotten somehow disconnected from the blade mechanism. Luckily, with the sort of pics I take, this isn't too much of an issue since my Pentax K500 shutter can easily compensate for the 2.8 aperture.
My question is whether your lens was ever cured of its ailment and how that was accomplished. Did you try to fix it yourself or did it end up at a repair facility?
I would love to get mine working properly, so maybe your response will steer me in the right direction.
Thanks and regards,
Bernd