So what's going on? Did the neck shift? Was it adjusted correctly? Or was it just done poorly? I actually get these jobs all the time. In this case, the guitar above had a couple issues- so we decided to correct them best that we could.
1) The neck is too straight.
It's a fine line between where it feels best and having adequate relief. After measuring the relief I found much more on the treble side than bass side, suggesting a twist. I'm talking like .005" difference but that's ample enough. So first, set the minimum relief to the bass strings. Then adjust the string height.
2) The nut slots were cut too wide/deep.
You can see in the first picture quite clearly how wide the slots are. Likely cut with a v-shaped file but still overly done. Nut slots should only be wide enough to allow the string to pass through it without binding. A few thousandth's of an inch wider and the string will not only lose tone but also vibrate within the nut slot, creating an unpleasant buzzing when the string is played open. Which was happening with this guitar. So after carefully cutting the lacquer around the nut, I knocked it out and made a new one.
Since it was in the shop, we also changed out the pickups and tremolo.
It's good practice to check that the new pickups work before installing them. Best way to do that is to test the impedance with a multi-meter. This also gave me assurance that it was a matched set and that the bridge pickup was indeed slightly hotter output. When swapping pickups, just replace the old wires with the new. Going one for one you'll never forget which goes where on a mess of a circuit like this.
Finished 'er up and the buzz has minimized and it's feeling much more solid all around. Learn more about these methods at one of our upcoming setup classes!