Ther tech is probably right the board is bad. Why spend more bucks for
another tech?

Just tell the service company you will pay for the board as long as it
fixes the problem? No workingg board no $$ for them.

You should be able to find the wiring diagram on stove or at local
parts place and look for fuse, which I doubt you will find, as a local
parts store this mst of come up before.

as to self cleaning ovens that run the temp up to clean........

they have superior insulation and are higher end units so they are
better made. frankly I wouldnt be without it, and only clean ours a
couple times a year preferably in winter, the excess heat helps warm
the house