There are many things that can be checked to make sure your pickups perform properly. Some important things are:
- Make sure potentiometers are clean and the right value and taper.
- Make sure all switches and contacts are properly soldered and connected to the right connections.
- Check for dirty or faulty jacks that can oxidize in time as the plating inside the jack becomes worn. Oxidized jacks can keep the guitar cord from making a solid connection and can cause static and crackles.
- Check for cold solder joints that can work intermittently.
- If pickups are weak and you turn the tone control to zero and the volume goes away then there is a break in the coil or connection.
- You register no DC ohm reading from a meter, the coil may be damaged or shorted.
- If the ohm meter goes to Zero (shorted circuit) when testing, there might be a short between the hot and ground connections or hot wires might be hitting a metal cover causing the pickup to short out.
- Make sure all the pickup components are tight and secure and not loose that can cause feedback or pickup howl.
- Keep steel wool away from pickups. It is used often to polish frets or other guitar work and the fibres can get lodged in the pickup and are attracted by the magnets within the pickups.
- Check for rusting or pole oxidation especially on single coil pickups. It can lead to ICPC (inner coil pole corrosion) and can eventually destroy the coil on single coil pickups.
- Check before and after the DC resistance of a pickup when removing metal covers on humbuckers and if the solder joint is not fully removed and can snag and damage the coils.
- Don't keep pickups with exposed coils loose in a guitar case, box or other containers that can cause the pickups to hit each other and damage the pickup. Humbuckers have metal legs that can scratch bobbins and gouge into coils.
- Make sure the magnets are properly phased in a pickup. In Gibson P-90 pickups, if the magnets are not put back properly the pickup will have little output or can be out of phase with other pickups. If two pickups are out of phase with each other, a magnet in one pickup can be reversed or the hookup in the coils will have to be reversed to electrically correct the phasing. By flipping the magnet over 180? degrees will magnetically phase the pickups.
- Make sure no screws or hardware are penetrating wires through drilled or routed cavities.
- Make sure the guitar work done is performed by a qualified repairman with the proper tools and experience. Make sure you use the proper testing equipment and follow proper safety procedures. Disconnect the instrument from the amplifier when using soldering irons as they could be a different polarity and could cause a severe electrical shock.
WRITTEN ON JUNE 12, 2015, BY