Home repair of toaster oven

[Temp] One day, my parent’s toaster oven stopped working. You’d turn the knob and only the toast function would work (there’s oven, broil, and air fryer mode). Since this oven isn’t super complicated or proprietary like a smart device or super dangerous like a microwave project, surely there has to be a simple fix.

Opened up, not much going on inside. Knobs controlled junction blocks that redirect or lower mains power. There is a switch that detects the door closed for safety and the light bulb is wired in parallel (?) so there has to be something open between mains – door interlock – junction block – heater coils – neutral

Two main spots of concern are door interlock and junction block. Door interlock is easy to check with continuity as it is just a limit switch. No concern there but I replaced it since it was cheap.

Big smoking gun was the first junction block that redirects power depending on mode (checks out with toast only working). This junction block looks unassuming but with tab connectors removed, one of them is charred. Possibly overheat/electrical fault and killed the metal tab? This wasn’t a issue documented in Youtube tutorials I was looking at (they mainly addressed the limit switch) but I verified it with continuity.

Yup that’s the reason. One online order later (+extra) and the oven was working brand new.

Ordered some heat resistance tab connectors just to be extra safe and up to code instead of direct soldering.