I have a few of the FA/FB units and they suffer from poor power pickup between the wheels and the motor. It doesn’t matter how clean I get/keep the wheels, the powers just not there due to worn pieces and a poor design that is prone to failure.
I decided that there had to be a better way. And, like always, it had to be easy using stuff I have.
Based on the design, I determined that a strip of brass with a couple contacts could do the job. A Forum member had given me a couple bags of relay contacts, and this was a perfect opportunity to use some. It’s now just a matter of soldering the existing wire to a piece of brass wire and tucking it under the brass bar. When the contacts wear, I can just remove the bar and solder in new ones. Another brass wire, unpowered, would also be placed on the other side and these can be used to tension the contacts and provide some spring to account for wear.
The wheels aren’t binding and the ohmmeter shows contact to the bar even without a tensioning wire.