And friends have other Samsung models. If a machine fails I do take a look and try the old battery disconnect trick (see google) but what is this about your S3? You seem to have fixed it.
What is the cause of samsung galaxy Tabs not turning on. Only blank screen? My findings
. Putting in or pulling out of headphones while device powers up or down. This happens when I turn on my Tab 4 & try to insert headphones at same time.
. New app causing problems. ...
My S3 phone had this problem with Google app update. The home button no longer worked until I uninstalled update
. Low humidity my have caused static electric discharge causing Tab reset
What are your findings if any?