I've had to rewire the assembly due to the wires being frayed because of a broken tube. I've replaced the tube but in separating the assembly a small part fell out and I have no idea how it goes back. The part I'm referring to is a brass piece with a spring and a small wheel on the opposite side. I've been able to assemble everything else except this part. There is a hole in a radius of the plastic base plate that seems to accept this piece but doesn't seem to work. Does anyone have a picture or diagram of this assembly or can explain where this piece is suppose to fit. Thanks.