Captain Bodgit: Fixing my Pentax K-30 exposure problem: #3 one problem leads to another!
New Genuine Repair Part For Pentax K30 K50 Ks1 Ks2 K500 K-30 K-50 K-s1 K-s2 K-500 Dslr Digital Camera Aperture Solenoid Plunger - Camera Flex Cables - AliExpress
Tutorial/Repair Pentax K-S2 with aperture-problem: Exchange solenoid - PentaxForums.com