I was nicely asked if I could take a look at a disabled toaster unit that stopped doing its job. Post-cleanup it looks like this: The quick repair job turned out to be quite entertaining in figuring out post-mortem how the unit failed and the questionable design decisions. It involves no complicated electronics and it might help other people figure out what to look for before buying an appliance. With another layer of failures stacked on top, this unit could have set the house on fire or shocked someone. Fortunately no damages were recorded, but the deep-dive might prove interesting to some people.
Electronics and programming interspersed at various levels of difficulty.