Laser Lock

A Laserdisc (laser Video Disc, Laser Vision Video Disc, Discovision, etc.)manufacturing error in which a foreign object, like dust or dirt, makes its way onto the aluminum core of the disc before the protective layer is put on, rendering certain parts of the disc unplayable. Essentially, the laser does not know where to go when the object blocks the groove. The playback on a disc infected with laser lock depends on being either a Standard Play or Extended Play disc. Laser Lock can usually be skipped over on a Standard play disc, but an Extended Play disc is not as easy to skip and you might not be able to play a lot of what's not infected. On a Standard Play disc, the footage will reverse or skip to another area on the disc. The screen of an extended play disc will turn the same grey that is shown when skipping, but it will stay that way until the laser can find its way back to a clear groove. This is most common with the earliest Discs from the MCA Discovision discs made in the late 70's.