Condolences to his friends and family. I'm very sad to hear this news. To say Ken will be missed is an understatement. It felt like almost every time I searched for a pinball or arcade solution over the years, I would find Ken's advice on some forum or newsgroup, always detailed and helpful, always willing to provide knowledge and advice. The vast store of information and experience he had was a benefit to us all.
As others have said, his legacy will live on thanks to the posts and info he has shared over the years. Current and future generations will find Ken's helpful advice all over the place, and be thankful for all that he's given us. Rest in peace, Ken.