Duet's are a pain in the butt..........You probably have both parts that need replacement...Ohm out every single wire in the harness that has anything to do with the wires from the Main control and motor control make sure every single wire ohms out and grab and tug on the wires as if the units shaking in spin mode......These unit shakes so much they get "ring cracks" at the solder connections on the main control very often.
Resolder black Relays connections at main board and replace relays on K1 and K4 if you can the door lock relays arc over and cause damage to the solder as well. Also put board under maginfying glass and check for cracked or other bad soldering and resolder anything that doesn't look right. Or take to your local electronics place and have them resolder if you can't or replace the main board.
F11 is essentially a communication error between the main control and motor control theoretically you should be able to check at the motor control blue wires and getting 5VDC and on the pink wires you should have 120vAC and that narrows down the problem..........IF it has those readings then the main control should be good but that's false sometimes. honestly i'd get rid of the unit and not invest too much money into it they are money buckets and as soon as you fix one thing another thing breaks alot of times.