My electric oven is broken. Nope, it's not the element. :(

[phucheneh]

I mean, it got hot enough before to cause all that carbon buildup. If you look at that 'before' pic after I had wiped a bit of the blackness off, there is a completely bare solder joint and some missing copper. I believe they literally burned away. Dunno if I've ever seen that...seen solder run, but not disappear.

I think the cause was correctly identified above. Very fast power switching caused by a bad breaker, which resulted in heat at the most vulnerable part- where the elements are switched on and off. I didn't hear it clicking, but the magnetic field in the relay may have been collapsing just enough to allow the switch to partially open before powering back on. I'm sure the contacts inside look like ass.

But this is just hypothesis. I'm gonna use it with the old board until a new one gets here, then I'll dissect it for a postmortem.

And I totally missed the electrical pun. I was too concerned with current events.


(see what I did there?)

 

[CallMeJoe]

edit: where would I obtain copper tape? Home repair store? Radioshack? Those are probably my only local options. I'm aware lead/tin is not the best bridge for burnt traces. But I was hungry.

Google it.

edit: Large gauge mag wire would also make an acceptable repair.

 

[CallMeJoe]

I would be a little concerned at what caused the fault.
That's probably L1->N line voltage (120VAC) there so if it flashes again it's going to scorch a bit more.

It could have been a manufacturing defect. Plated circuit boards sometimes have cracks or thin spots in the plating, which make resistive areas in the circuit path. In a high-current circuit, the bad trace generates heat that carbonizes the substrate, creating alternate current paths that generate more heat and widen the carbonized area. As the board cooks, the circuit path continues to deteriorate until either the overall current draw starts popping circuit breakers (or fuses) or the circuit finally burns open.


edit: in this particular case the above scenario is, of course, purely speculation.

 

[Howard]

How did the repair work? What are those traces for?

 

[grohl]

nice work, great problem solving

 

[Rubycon]

Good thing it wasn't the element, those do tend to get sparky!

http://www.youtube.com/watch?v=VNneQ_RY1Z0

:biggrin:

 

[phucheneh]

Cool! Maybe I can find an old oven and make my own cheap 220v arc welder.

 

[Rubycon]

Cool! Maybe I can find an old oven and make my own cheap 220v arc welder.

A microwave from a thrift store, blasting cap and flamingo with available anus is much more fun if so inclined. :biggrin:

http://www.youtube.com/watch?v=6U_uk3AWZh0

 

[phucheneh]

A microwave from a thrift store, blasting cap and flamingo with available anus is much more fun if so inclined. :biggrin:

http://www.youtube.com/watch?v=6U_uk3AWZh0

As much as I would like to complete welding projects with a flamingo anus...