Quick trip to a local open air market, and I found this unit. Probably long forgotten as it was not functioning properly. Mirror flipped up and lens exposed to whatever with tiny specs on front element. Some research on Pentax Forums yielded the fix and wanted to share with you here as it is super simple: - Open base plate with four Philips screws (The ones around tripod socket are smaller) - Remove circuit board (3 Philips screws) and remove it from slot, as you would remove a memory module from a computer. - With exposed mechanics you can see the pin to the left of the tripod socket which is stuck. - I freed it and mirror came down, cleaned goo from the mirror bumper cushion - Used electronic cleaner to clean old grease in the channel where mirror arm moves and one drop of watch oil to lubricate - Good as new now. See photos for the issue part. Hope this helps anyone having trouble with this.