Does anyone know hot to contact Robert Coslett last known to live at 1541 Castle Hill Rd, Walnut Creek, CA?

I used to share a house with Robert (Bob) between 1980-1982. I would like to re-connect with Bob. My e-mail address is LScheer@primus.ca if anyone knows of Bob's whereabouts. Bob used to own the piano and organ store in downtown Walnut Creek in the 1980's.