Guitar Repair, Guitar Tips, Gibson Guitars, Custom Guitars, Guitar Factory

Guitar Repair Tips 2

Warranty Repair Training
By Roger E. Fritz

Introduction

The procedures in this manual will explain the methods used by Gibson Musical Instruments.
This manual is intended to describe our methods, not to instruct, on every aspect of these
procedures. The author and Gibson Musical Instruments accept no responsibility for the
quality or suitability of repairs, or for incidental or consequential damages incurred, by anyone using this manual.

This manual is designed to standardize the methods used to repair Gibson guitars in house, and as a guide for warranty repair service centers. This manual is subject to modification when better methods become available.

Gibson' philosophy regarding antique or vintage instruments is to maintain them in as close to original condition as possible. Refinishing or modification of original parts greatly devalues them. Please treat the instruments with proper respect and care. Do not overspray or refinish a vintage instrument unless specifically ordered by a customer.

Customer satisfaction is the ultimate end result of service performed and each repair should have equal importance. We have some of the best guitar repair people working at Gibson and each day we strive to prove it with every repair that leaves the door.

Part One – Basic Guitar Setup

Restring the guitar with the appropriate gauge strings.
Tune to pitch using A-440 pitch pipe, tuning fork or electronic tuner.
Check the straightness of the neck to determine if a truss rod adjustment is
needed.
To adjust the truss rod: remove the truss rod cover and using a 1/4" nut
driver make a clockwise turn for a bowed neck or a counterclockwise turn
to straighten a back-bowed neck.
Once the neck is at optimum straightness, the string action should be
checked using a small ruler that measures in 1/64" increments.

Gibson electric specifications are:-

At the 12th fret- treble side- 3/64"
At the 12th fret- bass side- 5/64"
At the 1st fret- treble side-1/64"
At the 1st fret- bass side- 2/64"

Gibson acoustic specifications are:-

These measurements are taken with the ruler on top of the fret measuring the distance to the bottom of the string.

At the 12th fret- treble side- 5/64"
At the 12th fret- bass side- 7/64"
At the 1st fret- treble side- 1/64"
At the 1st fret bass side- 2/64"
To adjust the height of strings on an electric model, the thumbwheels on the tune-o-matic bridge will need to be raised or lowered according to the direction required. On an acoustic, the saddle will have to be shaved or sanded off the bottom to lower action or shimmed or replaced to raise action.
To lower the nut slots, special nut files are required that are available from guitar shop supply sources. We get ours from Stewart McDonald. Set nut slot depths to specs listed above for 1st fret.
Check for fret buzz. Using a medium pick or light finger touch, check all fretted notes for string buzz. If correct, move to the next step. If not, a fret leveling may be required. This is an advanced procedure and should be performed by a qualified technician.
Electric intonation adjustment.

This requires the use of an electronic tuner or strobe tuner.
Tune each string in the open position.
Fret the 1st string on the 12th fret with the electronic tuner set to high E.
If the tuner indicator reads "sharp" using a small slot head screw driver, turn the individual bridge saddle screw clockwise a full turn.

Repeat these steps until the tuner reads the same for open notes as well as fretted notes on the 12th fret.

* If the tuner reads "flat" turn the screw counter-clockwise until the tuner reads the same for open as well as fretted notes.

Repeat these steps for each string.

Acoustic intonation is more difficult to adjust because of the fixed position of the bridge saddle. It can be checked with an electronic tuner with microphone attached or plugged directly into the tuner if a transducer is in the guitar. Tune the string in the open position and then fret the same string at the 12th fret for a match.

It is very rare for every string to be in perfect strobe tune on an acoustic guitar, but some saddle adjustment is possible using a file. If the intonation is very bad, the bridge may need to be reset by an experienced technician. This is discussed in the advanced repair section.