Below is the closets I could find to your model number.
It is for a JBP26GXR3
Parts for GE JBP26GXR3 / - AppliancePartsPros.com

Looks like many parts are not available.

With luck it is just a bad element.
Does the oven come ready or does it stay in preheat?

In bake and pre-heat most units switch back and forth between the bake and broil elements. This is an older unit so it may use both of them at the same time.

If the unit takes longer than normal to come ready then that would also be an indication of a bad element.

Unplug the unit.
Check both elements for any visual indication of a burnout re: bubbled ceramic covering etc.

Undo the screw/s that hold the element to the back of the oven and gently pull it forward into the oven cavity.
Then measure it with a meter.
They are usually around 20 ohms.

It is a good idea to disconnect one side of the element before measuring as this prevents you from reading an alternate (parallel) circuit path.
Also a good idea to clip something to the elements wires so that they do not disappear into the back of the unit.

If both elements are OK then it is probably toast re: the control thermostat is bad which is not available.

It is very important to unplug the stove when doing the above as one side of the elements is probably still live even with the oven shut off.