Fixing my Pentax K-30 exposure problem: #4 more details on solenoid

I spent a jolly day thinking about the exposure solenoid and doing a few checks.

Everyone has a theory about why the green solenoid is problematic.

I've tried to work out how it operates...

Fixing my Pentax K-30 exposure problem: #3 one problem leads to another!

Having reassembled my K-30 with the replacement solenoid, it was time to test it.

Unfortunately it failed the test, with all photos underexposed.

I think my problem was due to a truly stupid mistake.