Fuses do not protect electronics. Fuse blows after electronics are
damaged. Fuse is to protect humans from a now existing short circuit.
A reason for electronics damage was no 'whole house' protector with the
essential 'less than 10 foot' connection to earth. Most electrician
don't yet understand this well proven concept that was not necessary
before transistors.

More likely what happened: a transient caused oven and other
electrical damage. Transient that was not earthed at the service
entrance found a destructive path to earth via the oven. Power was then
lost. When power returned, that AC power found a now damaged oven
which blew the breaker.

Having replaced an electronics board, there should be little left to
replace. For example, the transient could have found earth via a
thermocouple which is why temperature control is inconsistent.

If the problem is not obvious, then one reason to repair is to learn
why failure happened. You must make a decision as to which is the less
risky / expensive option.

Meanwhile effective 'whole house' protector solutions are
manufactured by Siemens, GE, Square D, Intermatic, Cutler-Hammer, and
Leviton. Effective protectors are sold in Home Depot, Lowes, and most
electrical supply stores. No effective protector has been seen in
Sears, Kmart, Staples, Radio Shack, Circuit City, or Walmart. The
effective protector only makes a temporary connection to earth which is
why that short earthing connection is critical. A building that does
not meet or exceed post 1990 code reqirements would not have sufficient
earthing. Manufacturers with lesser reputations such as APC, Belkin,
and Isobar are definitely not on the list of effective solutions.

Meanwhile, above is secondary oven protection. Primary protection
must also be inspected:
http://www.tvtower.com/fpl.html

Further details are at: http://www.psihq.com/iread/strpgrnd.htm
> Ten years ago it would have been rare for anyone to talk about the
> importance of low resistance grounding and bonding except where
> mainframe computer systems, telecommunications equipment or
> military installations were being discussed. Today, we live in a world
> controlled by microprocessors so low resistance grounding is now
> critical and is a popular topic of conversation.
> The electrical grounding system in most facilities is the electrical
> service entrance ground. In the past it was often "OK" to just meet the
> minimum requirements of the National Electrical Code (NEC). Today,
> the requirements of the NEC should only be the starting point for
> grounding systems and bonding.

kbarch wrote:
> It's a long and sorry story, but I need to replace a 24" Kichen Aid
> double convection electric wall oven that was less than 3 years old.
>
> In brief, we had a power outage, and then apparently a surge when the
> power went back on. It tripped and broke the dedicated 30 amp circuit
> breaker which was properly sized but old. Electrician hypothesized that
> the power got through the breaker, fried the motherboard of the
> appliance and was kicked back by the surge suppressor of the appliance
> which finished off the breaker. Who knows? We replaced the breaker. We
> also replaced the motherboard which was covered by a 3 year warranty.
> But the oven never worked right. Neither oven heated up right and kept
> cycling on and off erratically making impossible to bake anything that
> had to rise.
> ...