The vertical lines are completely gone as of this morning, after leaving it turned off overnight *whew*. Is it all right to charge the PlayBook while it is powered off?
While I would say is SHOULD be okay, maybe you want to monitor it - charge it during the day when you can maybe periodically observe it. Check if it is either cold or too hot. You might turn it on every hour or so, too.
This always happen to me when I turn the playbook on while it is charging... the lines go away eventually after its left off as Joshua said... sorry to resurrect an old thread but it just happened to me