Originally posted by Landak I have a much-loved K-S2 that has around ~60k shutter actuations. I've noticed recently that the noise it makes at the typical speeds I use has gone from being a reassuring "clunk" to having a note of "boing" at the end –*sounding a little bit springier. It's really subtle, but definitely different. Could this be the sign that I've nearly worn it out?
The solenoid in the K-S2 is made out of PET which wears quicker than the PTFE of the older Japan-Solenoid which was used in many Pentax bodies up to the K-r (K20D, K10D etc. as well)
I often noticed a "better" sound when I had exchanged this green (PET) China-made solenoid against the white (PTFE) Japan-Solenoid.
Also series photos are faster!
The PET-body of the China-Solenoid acts as a bearing for the plunger which moves very fast in and out when actuating.
It is anyway slightly larger, i.e. more bearing-play then the PTFE body. Each time the plunger actuates heats is dissipated and thus the PET body
wears quicker due to a lower meltingpoint.
You can see the difference here:
https://www.pentaxforums.com/forums/members/85274-photogem/albums/13040-diff...ure123013.html
and here when the plunger is out:
https://www.pentaxforums.com/forums/members/85274-photogem/albums/13040-diff...ure123014.html
And yet, high shuttercount was always safer for Pentaxbodies with the Chinasolenoid than low shuttercount, not because of wear but because low shuttercount usually indicates longer periods of non-use which is the more common cause for ABF.
The danger with a worn solenoid is that the plunger moves more sloppy (more bearing play):
https://www.pentaxforums.com/forums/members/85274-photogem/albums/13036-gree...ure123005.html
while it should move like this:
https://www.pentaxforums.com/forums/members/85274-photogem/albums/13035-whit...ure123001.html
Thus is can block differently and then goes out of alignement. This can be the result:
https://www.pentaxforums.com/forums/members/85274-photogem/albums/13069-gear...ture128375.jpg
So the solution could well be to swap the solenoid.
@reduno:
The mirror up is done by this motor, which sits on the very right side on the diaphragm-block:
https://www.pentaxforums.com/forums/members/85274-photogem/albums/13179-diap...ure124607.html
The shutter actuates by two strong solenoids which sit invisible underneath the plunger.