Hello cavow,
I read your posting yesterday because I have had same problem somehow with Canon powershot 495.
I can confirm that playback button causes the problem.
My daughter and I were visiting water caves last year, having high humidity in and some water dropping on the floor when suddenly the camera started to behave abnormal.
As I opened the camera I saw a contamination underneath the play button caused by a little hole at the backside of the button where water came into the inside of the button and produces a short on the button.
I used air pressure to open up the glue on the plastic in the area of the button and then used a little needle to scratch around the gap of the two contacts from play button and then stick all back together.
This all sounds simple but is very tricky. If you have somebody who is an electrician he might solve this for you.
Good luck,
Lichi
