I have a Force 10 4-burner stove from about the same vintage and, unfortunately for us, that was right around the time that Force 10 was sold. The previous owners apparently kept poor records as to which components they were installing so getting replacement parts
from Force 10 is nearly impossible.
Our oven has the exact opposite problem - it only cooks at Wide Open Throttle, regardless of where the thermostat is set. A tray of cookies cooks in 8 minutes but you have to watch them carefully or they burn.
We're seriously considering replacing our stove.
Fair winds and calm seas.