Hi. I'm Smitty. I am a professional appliance repair consultant here to help you diagnose, and repair, your appliance.
After reading through the manual it seems that something other than ther main control board is causing the unit to reset.
This is what you are seeing on the display (see first screen shot below).
As you are only seeing the first part I can guess that the control board is loosing power somehow when the oven is sent the preheat or bake input.
As the main board works in cooperation with the power board and the power board is what supplies the power to the main board it would be logical that the power board is the real culpret here.
There are of course diagnostics that you can perform to confirm this.
To help you understand how your unit works and do the diagnostics please click here to download a copy of the service manual for your unit.
If you start at page 22 it will take you through the system and expalin how it all works together. Im sure that with a little reading you will be able to figure this out.
Of course if you have any questions please let me know.
Thank you for the opportunity to serve you. Best, Smitty**How to rate your expert**
Thank you for sending this information. We will read through it thoroughly. We have had the display board (Part 489262) replaced twice. So what I am getting from your response is that you think it may be the power board?