4XX - 4XXX Brush motor MOSFET

If your brush motor will run when connected to a Roomba battery or 9 volt battery but won't run when connected to the Roomba main PCA then it may be due to a U11 circuit device failure. On most of the circuit boards used today there is an additional location next to the U11 circuit that you can install a heftier MOSFET to run
that brush motor

You can order a replacement MOSFET by selecting  the paypal button below.