Unplugging and replugging a connector really can fix it, and here is why
The old trick of pulling a plug out and pushing it back in has a physical basis. Metal contacts slowly grow a thin film of corrosion that raises resistance and causes flaky connections. Each time a connector is reseated, the contacts scrape off a microscopic layer, exposing bright, unoxidised metal underneath.
An electrical connector is simply a device that joins parts of a circuit, or separate circuits, so current can pass between them. Most have a gender: the male plug fits the female socket. Thousands of designs exist for power, data and audio, falling broadly into four groups: connectors fixed on the end of a cable, ones mounted on equipment panels, ones soldered onto circuit boards, and splices that join two wires for good. No single design suits every job, which is why the variety keeps multiplying; sometimes a manufacturer even picks an incompatible connector on purpose, to control what can be plugged in.
The metal inside is usually a copper alloy, chosen for conductivity and ease of shaping, but copper corrodes and resists solder, so pins are often coated. Gold is the favourite for delicate signals because it forms no surface oxide and does not tarnish in air, which is why circuit-board edge connectors glint yellow. Engineers have experimented with palladium-nickel and nickel with a whisper of gold to cut the cost.
Connectors fail in telling ways. Repeated plugging can cause fretting, a kind of wear-driven corrosion. Heat can set off a vicious circle: warmer surroundings lower insulation resistance and raise conductor resistance, which makes more heat. Clever design fights back. Keying, such as the notch on an XLR microphone plug, prevents a plug going in upside down or into the wrong socket. Some pins are made longer so the safety ground connects first and disconnects last.
For the harshest settings there are hyperboloid contacts, in which each socket holds a ring of fine wires twisted into an hourglass shape. As the pin slides in, the wires wrap around it like springs, surviving shock and vibration while needing about 40 percent less force to insert.
Source: Electrical connector
