What is burn-in?
Burn-in is a test in which a system or component is made to run for an extended period of time to detect problems.
Burn-in may be conducted to ensure that a device or system functions properly before it leaves the manufacturing plant or may be part of a repair or maintenance routine.
An end user may use a burn-in process to ensure that new equipment is functioning properly, for example, running a new computer for several days before committing it to serious use. If any of the components are defective the problem will usually show up within this initial testing time frame.
When a faulty device or system is brought into a repair facility, the malfunction might not occur until the hardware has been warmed or cooled to a certain temperature. Humidity may also be a factor. Under these circumstances, a burn-in must be performed and environmental parameters varied until the problem is found. The equipment is powered-up and then left to run continuously for hours (or sometimes for days) until the malfunction is observed and can be diagnosed.
The term burn-in is sometimes used in reference to a phenomenon in which faint, permanent "ghosts" appear on video displays that have displayed fixed images for long periods of time. This problem is also known as screen burn or phosphor burn. In older cathode-ray-tube (CRT) displays, screen savers were used to prevent burn-in. Newer computer displays rarely exhibit burn-in except under extreme conditions. However, burn-in remains a potential problem with large-screen video displays such as those found in home theater systems.