Steve, I didn't consider this but I completely agree. My first thought was: Here we have another serious serial failure problem not only related to K30/K50 but also to the K-S1.
So here we go:
#269
And here is the first
K-S1 with an aperture block failure.
Mine has started two days ago with black (heavily underexposured) pictures.
Battery in and out temporarily solved the issue but today the mechanism totally went stuck.
But I have made a very interesting discovery.
Carefully heating up the body (battery out) to 40°C on a radiator cured the problem - completely!
Unfortunately the black picture phenomenon returned as the camera cooled down to normal temperature (20°C).
Now I have to shoot two to five pictures before I get properly exposured photos.
May be this finding will help us finding the cause and hopefully a permant solution.
#272
AFAIK no one did report a faulty
K-S1 in the forum's survey. But that's not the point.
Meanwhile I'm still testing. Results are promising but not satisfying so far.
The camera went from totally dead to a working state now after 1 to 3 black shots.
Perhaps somebody can repeat my procedure and post their result?
Heating up the camera to 40°C should be safe. User manual says 0 to 40. Battery and SD-Card removed. Carddoor open.
I place a thick book between the camera plus thermometer and the radiator.
I let the camera heaten up for 2 hours. Then gave it a burst shot (30-40).
I let it cool down for 2 hours and gave it a burst shot. Exposing it to different light will engage all aperture values. SD-Card not needed.
The second time I have put the camera upside down.
Now I'm continuing with both sides. Same procedure.
If this will fail I'm going to open the camera and try the repair procedure as it's described in this thread.
#273
Now, one day after, the camera is working as it should.
Correct exposure with both aperture and shutter speed from the beginning.
I do believe that heating up the camera's side where the solenoid is positioned did the trick.
I only can confirm this for my K-S1 and of course I don't know how other models will react to this method.
But I recommend this procedure before trying a self repair or sending it to a repair center.
Kind regards
Heribert
Who's interested in the whole story should read all posts in the K30/K50 sector.