Replacing a battery in a UPS. 2010's.
A mains powered electronome from the mid 1900's. Susceptible to mains timing changes. Neat. Vintage 1950's/60's.
Tearing down a scanner for parts. 2000's.
LED Lanterns are a recent fad. See how a PCB is cut into four columns and soldered together to make the lantern light. This model failed due to the Potentiometer light adjustment mechanism. 2010's.