The P-90 is a single-coil pickup developed by Gibson in the late 1940s, and it was a predecessor to the dual-coil Gibson Humbucker pickup. Coveted for its signature tone, the Gibson P-90 continues in use today, and P-90-style pickups and covers are made by most major pickup manufacturers. The replacement of P-90 pickup covers is a straightforward operation that involves the removal of two screws.
Loosen the guitar strings for easier access to the pickup by turning the tuning keys counter-clockwise.
Remove the two mounting screws by turning them counter-clockwise with a screwdriver. For "soap bar" style P-90s, the mounting screws are the two smaller screws on either side of the fourth and third string pole-screws. The mounting screws for "dog ear" style P-90s are on the outside edges of the pickup.
Grasp the pickup with your fingers and pull straight out. The cover and pickup will come out as a single unit. Do not pull on the pickup wiring while removing the pickups; the wiring may become loose or disconnected.
Grasp the underside of the pickup and pull the cover off with your fingers. The cover is mounted to the pickup by friction and should be removed easily.
Place the new cover over the pickup and press down to line up and seat the pickup pole pieces into the holes in the pickup cover. The covers are symmetrical.
Tuck the pickup wire into its channel when replacing the pickups. Placing the pickup over the wire will cause uneven pickup height and pose the danger of driving the mounting screw through the wire.
Insert the pickup with installed cover into the pickup cavity of the guitar.
Replace the mounting screws by turning them clockwise with a screwdriver.
Re-tighten the guitar strings by turning the tuning keys clockwise and test for operation.
Check the fit of the pickup covers to the pickups before installing on the guitar. The products of different cover and pickup manufacturers may not be compatible. The mounting screws supplied with the new covers need to be the same length as the original screws. If they are not, use the original mounting screws.
Do not glue the pickup covers to the pickup. Some glues may damage the pickup housing material and make future cover changes difficult or impossible without damaging the pickup. Use the same style of P-90 pickup cover (soap-bar or dog-ear) that is installed on the guitar. A dog-ear cover will not fit in a soap-bar pickup cavity and vice versa.