 Once the guitar equipment has been set up onstage, the guitar tech does a soundcheck to ensure that the equipment is working well.If there are any problems, the guitar tech replaces or repairs the faulty components or equipment.Since guitar techs need to soundcheck the instruments and amplifiers, they must have basic guitar-playing skills, a musical "ear" for tuning, and a familiarity with the way guitars, amplifiers, and effect pedals are supposed to sound in the style of music of their band.