Bought my K-30 on the famous platform, after a while the typical aperture problems appeared...first frustration....
...found the instructions of changing the green selenoid to the white one... opened up the camera.... damn...second frustration...it already had the white one...
...I gave up hope, it seemed that I had to accept that I've been cheated...
....then...thanks to a post on a german pentax-site...
I found the advice to take eneloops within the battery holder instead of the block-battery -because there are some further electronic issues expected, not only the selenoid-
....and...drum-roll...no problems with the aperture since then...
A second battery holder and enough loaded eneloops (the block-battery only for sensor cleaning or firmware)
Should the solving of the problem really be that easy? ...what a waste of time until then...
Give it a try and tell me!
Regards and have sunny times!