Diplomat 8252 Popping Noise and Burning Smell?

Machine 8 years old started popping near end of cycle initially and could smell burning. Next wash was ok but gradually got worse.

Decided to get someone in and replaced heating element. Problem remained.

Took front lower panel off and noticed sparking from thermostat at underside of machine on the left hand side. Seems ok on a cold rinse but sparks and smells when on hot rinse/wash or drying cycle.

Replaced the lower thermostat also but problem still persists.

Wondering now whether to buy a new dishwasher rather than keep replacing parts unless someone here might have some advice on what might be wrong.

I believe there is a door thermostat? Could that be causing the problem?

Many thanks in advance.

Neil.