Level of DifficultyReally easy
Time to do repair30 - 60 mins
Age of Appliance5 - 10 years
First, TURN THE POWER OFF AT THE BREAKER BOX!
Unscrew the (built-in) oven from the wall / cabinet (4 screws). Unscrew the cover in front at top where the LED display is held, and pull it back, then pull two sets of wires off of the LED display PCB, so it can be put aside. Pull the oven out of the cabinet, sit it on a chair (because the 240V power feed metal cable is still attached). Unscrew the 7 1/4th-inch hex head screws holding the metal top cover on; remove the cover, which exposes the wires and sensors, etc. Unscrew the "relay board" PCB (1 screw) and detach it from the side, leaving all wires attached to the terminals. Then, one by one, remove the wires from the old PCB and attach them to the corresponding terminal on the new, replacement PCB. Screw the new PCB back onto the side of the oven top inside, screw the top metal cover back on, attach the wires to the front panel LCD and then screw the front panel back on. Push the oven back into the hole in the cabinet and screw it into the wood on the side and bottom (6 screws total).
Finally, turn the power back on (flip the circuit breaker on). Then observe: your oven is now no longer a digital boat anchor!
The only reason it took me longer than 30 minutes to finish this was that I had to recruit someone to help me lift the oven out of its cabinet. After doing so, however, I realized that I could have done it all by myself, simply by sliding it out onto a box or chair, but I didn't realize that ahead of time. It's not really that very heavy (but I would not recommend anyone who's not strong trying to do it alone, regardless). Anyway, if I had to do it again, it would only take about 10-15 minutes to accomplish.
The part itself colst about $180. When my usually very reasonably-priced appliance repairman quoted a price of $450 to $500 to do this repair, even after I told him specifically which part was obviously bad (which he would have to order or pick it up), I decided that only an idiot would be unable to do this repair by himself.