Testing aperture block failure in M-Mode (i.e. golden standard):
I don't understand why I never became aware of this because this should have "jumped into my awareness".
Possibly because I always did the test in simple Av-mode or TAV-mode.
Usually I take a F50/1,7 or similar and set it wide open = f1,7 and do a test shot:
Picture very dark = stuck solenoid
Then the (logical) opposite test, in this case f22 + test shot:
Picture fine (because the solenoid doesn't have to open!)
The other easy way of testing is liveview as I have explained:
Right away when set on liveview a Pentax with functioning solenoid will set itself to f4 i.e. relative open
Aperture - Wikipedia
But with stuck solenoid the iris will remain closed = f22 and will
look like this
I have already done
tests checking the function of the solenoid when using the green button which is in M-Mode.
So today I had the chance to repair another K30 and finally did the test.
The iris did nothing after I followed those instructions.
So I opened the K30 to check it inside.
I unsoldered the wires: No change.
I built the white solenoid in: No change
So to test it again I opened a K100D. The K100D is a bit more difficult to test with seeing the solenoid in action because one has to reassemble it partly for being able to install the batteries.
I intentionally took a working K100D with high shuttercount because I then installed the bad green solenoid into this K100D!
The result was as expected: As well in the K100D the solenoid will not act in M-Mode!
On this photo of the K100D with the faulty solenoid from the K30 you can see one cable of the solenoid unsoldered:
It doesn't matter if the solenoid is faulty, soldered or unsoldered, has a filed plunger or not, you even can take the solenoid out completly, the camera will still work in M-mode because in M-Mode the solenoid is not working.
As explained in the previous tests here:
Dark exposure problems on K-30 or K-50? Discussion Thread - Page 20 - PentaxForums.com