The wonders of modern technology!

You haven't indicated what type of "control" it is
(pot, optical encoder, rotary switch, etc.) -- hard
to guess for someone not owning a similar oven!

Also, are you sure the problem is in the "knob"
and not in some bit of electronics that the knob
"talks to"?

E.g., if it wwas *my* oven, I would try swapping
the connections for that "knob" with those of
a similar knob and see if the problem "moves"
with the knob or stays in place regardless of
the change. Likewise, follow it back into the
bowels of the oven and swap things *there*
(i.e., the controls for the actual heating elements)
until you have positively isolated the source
of the problem. Else you are likely to spend
all that cash on the wrong part...

Thanks. The switch is a rotary mechanical switch. There isn't any
similar knob (switch behind the knob, actually) available on my stove.
I need to buy one and try it out. It's acting like the connections are
dirty or worn or both. Rotating the knob 360 degrees fixed the problem
last night. But eventually I will have to replace it, I think. May end
up ordering a used switch from eBay and hoping I get a good one.
Apparently they can be had fo about $16 plus shipping. Thanks to
other poster for that info.

Thanks again.