Many electronic gadgets die and become unusable. The reason is often "bad caps", electrolytic capacitors that are failing. In some cases this is impossible to see, but in many cases a bad cap is physically damaged. A probably good cap: Some bad ones: These pictures were taken in a computer power supply. The computer were malfunctioning with bluescreens and the USB voltage was about 3.5 volts instead of the 5 volts it should be.