1. push the scan button on the printer 2. error "check cable" 3. but i can print, and i can access printer web page - printer ip is 192.168.1.11 4. run installation check - show scanner ip as 192.168.1.7 - dhcp changed 5. install check said to check control panel scanners and cameras 6. get properties on brother mfc-7820n lan - in network setting - specify machine by address was using old address - i changed it to specify machine by name so future ip changes won't impair printing 7. all is working