Sometimes it helps to take off the brushes to be able to see what is going on with the needles when they come out. Scenarios when doing this can be useful would be when a yarn is not being caught properly or a transferring operation is not successful.
The main task of the brushes is to open the latches of the needles as they come out. An open latch is essential for the hook of the needle to be able to catch the yarns or transfer a stitch. When brushes are taken off then, do a visual inspection to make sure all the latches are open. If they are not, you can use the removed brush manually to gently brush the tip of the needle and open the latch. Having said this, don't use the machine without the brushes for more than a few passes. Latches sometimes bounce and get closed, which would lead to issues in your knitting.
To take off the brushes, loosen these 4 screws marked below and slide the brush to the side. Do not remove the screws, loosening them just a bit is enough for you to release the brush.
A bind off seen with more detail without the brushes.