On the pentaxforum.com website there are photos here and there showing magnified views of left and right of the mirror box (one somewhere also shows what's under the top cover), just to give an indication of what you're up against identifying things that are and may not be working correctly. Very few wires. I have not been able to find the photos but think they related to a sticking mirror, which is often caused by foam inside the mirror box deteriorating and making its way inside the camera where it drums up trouble. Re-skinning after repair is a very tedious and fraught process (very aggressive adhesive that hides tiny screws); DIY types often by new skins from eBay and cut to size. Personally and frankly, if my 67 starts misbehaving, it's take a deep breath and say, "thanks for the company, babe!" and discard it. And move on to something else. For now, it is "the chosen one", LOL!
A mint condition Pentax 67 body with L/ wooden grip was listed on eBay here in Australia yesterday, for AUD$750. Separate listings for a 105mm f2.8 ($250), 90mm f2.8 ($300), wooden grip etc appeared to have all been sold when I found them with 3 hours to go before finishing. I would have pounced on that camera as a second body if not for existing financial commitments (new tyres for car of the same cost) — or at least the 90mm lens, drrrrrat!!