The selector control unit for the upper oven which selects bake, broil, clean, off etc. works but it is loose, or broken as it moves up/down and around not just turning clockwise which makes it tough to turn the upper oven off as you have to move it just right or it stays on.

There are four control knobs or selectors, this is for the upper oven, far left as you look at the oven or closest to the clock, the knob attaches to this by a stem which protrudes through the panel with a disc attached which all lights up when turned on but goes off if turned off.

What is the part or procedure to repair/replace/tighten and can I do such if I had a schematic to know how to access?

Thanks for your help.Steve