GE Profile electric range/stove/oven with an oven control board issue

I have a GE Profile electric range/stove/oven with an oven control board that I suspect is not functioning correctly. 

Symptoms:  The burners on top are fine and work as to be expected.   The oven, however is not.  The read out is very dim, but still readable.  No error codes have appeared.  I am able to turn on the oven, for example to the Bake function and set it for 425 degrees, but after about 20 seconds, it shuts off.  Same thing for the Broil function.  However, here is something interesting.  I turned on the self “clean” function and the door locked and it actually heated up and worked.  After about 20 minutes, I stopped the clean function by tapping CLEAR/OFF.  The oven stayed locked until it cooled down sufficiently, but was still hot.  I was then able to set the oven for bake and 425 degrees.  It functioned as it should.  It got up to 425 degrees and notified me through a beep that it was ready, I set the timer for 20 minutes, popped a pizza in the oven and it worked flawlessly.  But today, I can’t get it to even go into the self-clean function without turning off by itself within about 20 seconds.

I saw from your website that you have what looks to be an identical control board with a listed price of $119.99 for repair.

Can you confirm whether or not you are able to repair my oven control board or not and how much it will cost?

Lastly, it’s possible that after testing that my oven control board is functioning correctly, so that would probably indicated a faulty temperature sensor or thermostat sensor.  I’d still like to get the dim screen repaired and have the entire board checked at any rate.

Thanks,