Hi, I've got the same problem like described here: https://de.ifixit.com/Antworten/Ansehen/... And I solving it the same...

Hello guys, my camera has the exact same issue and thus I opened it to fix it. Now I've fixed it and mount all parts together. Just the ‘preview switch (unit)’, how it is called in the manual, seems to not fit together anymore. There is a switch which seems to me like being in another position and thus it doesn't fit anymore. Though I can't remember having changed any position of any switch and further took a lot of care not to do. Anyways, does anybody know how to bring the switch in the right position or how to mount it again? Greetings Sebastian