Replaced the Pwb (pcb) Asm Sub part number AP3882298 for $70.87.
This part was not hard to replace but was hard to get to. Our GE Advantium microwave is model SCB1000KWW01. You only need to remove the top 3 screws and 2 on the sides. But there are 2 that can only be reached through the holes in the top. You'll need a magnetic screwdriver.
Once you get that apart, it's pretty easy to change out the board.
Ours is working much better now. Not sure it is completely fixed but much better.