As someone who’s bought a used guitar that turned out to be a dud, this is a necessary subject. A long time ago, I bought a used Jackson Dinky DK2M for a very reasonable price that I can’t remember now. Excellent finish, (licensed) Floyd Rose tremolo, compound radiused fretboard, and it even had an EMG 81/85 pickup set installed. These were all the things I was interested in at the time, but as it turns out, the guitar was being sold on to me for a reason that I didn’t anticipate.
Part I: How to Sight the Neck
The neck turned out to have an inoperable twist in it that led me down a lengthy path of trying to correct a defect that was rooted right in the wood…myself and three other experienced luthiers went through the process of trying to compensate for the will of the wood pulling away from the action – countering with the truss rod, carefully cleaning up the bolt-on neck heel and pocket, re-radiusing the fretboard and refretting, and finally a shim.
Each time, the thing just wanted to keep pulling away – the shim seemed to do the trick but I was done with it by then. I prefer to have wood on wood contact, and a guitar that requires such an “artificial” compensation just to play wasn’t something I wanted – I didn’t want to always have the worry of whether or not the wood was going to settle at last and stop bothering me. I built myself a baritone 7-string instead of buying another used guitar.
I could have avoided all that hassle with a simple once over to sight the neck and check the wood grain pattern on the neck, which was clearly indicating that the neck was carved from a twisted piece of maple.
I purchased the guitar on eBay, so I didn’t have the chance to do this anyway. I’m not suggesting buying online is no good, but it does limit your ability to make a decision in complete confidence. Without further whining, I present you a list of methods that you can use to minimize your risk in purchasing an electric guitar;
Checking for abnormalities in the fretboard
For our purposes, we’re not going to be checking the relief for a setup, but rather just to make sure that there’s no abnormalities. Do you really want to buy a guitar that will immediately need the fretboard re-radiused or an entirely new neck? Any time you buy a used guitar, you’re inheriting the previous owner’s problems with it, and the neck is liely going to account for 90% of them.
Warping
It makes sense to start here after that introduction, but it’s also being mentioned first because it’s probably the biggest issue that you could easily miss if you don’t look for the right stuff. Here’s a graphical representation of the features you’re hoping your potential buy isn’t going to have:
This issue is a result of poor wood selection, specifically when wood that hasn’t had the time to dry and settle properly (curing) and/or has been cut from a portion of the tree that’d bent while it was growing. When sighting the neck, we’re looking down each side of the fretboard and noting the differences.
Cracks
You’d think this would be an obvious one, but sometimes it’s really not too easy to see. Particularly if there’s been a good repair job done on it. If the seller has been honest about it and the guitar plays just fine, you’re still taking his word on it because you’re likely not going to have the luxury of making certain that the repaired neck is holding everything in tune under the string’s tension.
Cracks can be repaired well enough by a skilled luthier to make the guitar play as well as it did originally, but you can’t really know if that’s the case. When it comes to cracks, 99% of the time you’re going to find it right where the headstock transitions into the main portion of the neck on the back:
Rising Heel
Wood is a hygroscopic material, which basically means that it breathes water from the air depending on the climate – which causes the wood at the heel of the neck to swell and rise up (usually somewhere around the 14th fret and upward). Sometimes people call it a “ski-jump”.This isn’t a definite deal-breaker, and sometimes you won’t notice the issue if the truss rod is adjusted to compensate to some degree beforehand. It will make a nice low action harder to achieve though, and repair involves radiusing the fretboard (and subsequent re-fretting).
You can try to save a little effort on the job by just leveling the frets lower at the heel. That’s if the rise is slight enough, they can be pretty dramatic. Look out for it, and if you happen to notice one then you can reassess from there.
Fret Divots
The quality of the frets upon purchasing a used guitar can indicate the level of care from its previous owner. But don’t make any judgements if the tops of the frets are worn (only consider getting them redressed), nothing wrong with someone playing their instrument.
You do want to check for any dents because not only is that a sign of mistreatment (accidents happen too), but it’s also going to hinder your playing – the notch can catch the string when you’re bending a note.
Luckily, you can still get the fret pulled and replaced for a reasonable price, but the dents are usually a result of the guitar falling forward or being struck hard enough to make the string cut into the fretwire.
Part II: Assessing the Neck’s Wood Quality
Twists – As we learned before, a warped neck is a major issue. Sometimes sighting the neck reveals a very obvious defect, and sometimes it’s much more slight. You may wonder why the guitar keeps on going out of tune quickly or you get strange patches of fret buzz that you can’t rid yourself of.
It’s particularly telling if the adjustments make a temporary improvement before going off again. It’s possible that the wood selected for the neck wasn’t settled and wants to keep pulling the direction of the grain as it continues to cure – this could be an unnoticed twist in the grain or just a plain bad cut.
You won’t get the chance to observe this process when you’re just showing up to buy the thing, but you can look for some flags in the grain pattern if the guitar has a natural or translucent finish.
Wood that hasn’t been cured long enough and is still settling is going to want to pull the direction of the grain. So the obvious thing to look for is the wood grain taking a detour that’s inconsistent with the rest of the pattern. You can learn all about ideal wood cuts and their grains here.
If you can note where the grain is turning off then it’s your job to go back and sight the neck again with a particular focus on that area – make sure to compare each side as well.
Take a look at the article linked above for some helpful diagrams on the matter.
After that, you’ll have a good idea of what your neck’s patterns should look like, and you’ll be able to spot abnormalities that’ll give you a point to pay particular attention to when sighting the neck, as well as give you an excellent talking point with the seller.
It’s probably unlikely, but if you can get a look at the butt of the neck (bolt-ons only), you can have some extra assurance about the quality of the wood selection. Only in select cases is the wood going to be flat-sawn, all the rest will be quarter-sawn.
The more vertical the grain, the better. If the neck is made with laminate pieces of quarter-sawn wood, you can settle your fears since the resistance against warping is going to be significantly increased.
Part III: How to Test the Wiring
If you’ve sighted every inch of the guitar’s neck and feel that there’s nothing warranting major repair, then your next move is to plug it in and cycle through all of the options on the circuit. Bring a little practice amp with you that you know has a clean tone, just in case the seller doesn’t have an amplifier to run through or, if he’s a sleazy character, tries to blame static or other defects on the amplifier knowing there’s an issue with the guitar. Not to be paranoid about everything, but it’s not much different than buying a car in the sense that you get people selling lemons and it’s not going to hurt anyone to be cautious. Might as well bring a 9 volt battery with you as well if it’s an active set.
Output
Slide the jack in the output with the amp already on, listen for any pops or brief cut-outs on the way in, then put a little pressure on the ¼” jack and push it around in the output hole (don’t try to break it off, obviously). Just enough to check that the output is installed snugly and the soldered connections are all well.
You’ll be listening for brief moments of unresponsiveness (bzzz) or crackling and pops (like the cereal).
Pots
Roll each pot up and down while the guitar isn’t making any noise to make sure you can hear if there’s any crackling. This goes for the volume and the tone knobs. If there’s an unpleasant scraping noise, it’s likely that the pot has a little bit of corrosion (described as a “dirty” pot).
All you need to do this is is a can of contact cleaner and 5 minutes of your time.
You’ll just want to spray a bit into the potentiometer through the slot where the resistance plate is, then turn the knob all the way back and forth to clean across the plate. No sense in not cleaning the others while you’re at it.
Constant Humming
If you’re hearing a continuous humming or buzzing sound (to varying degrees of volume) then you’re likely hearing a poor ground connection. It could be from a poor cable as well, but 9/10 times it’s going to be an improperly grounded circuit.
You’ll likely hear the sound drop off if you ground the circuit yourself by touching parts of the hardware. Open the back of the guitar up and trace the ground circuit from the pickups to the output to try and locate the culprit.
While you’re back there, you’ll wanna check all of the solder joints to make sure there’s a complete connection with a nice shiny blob of tin at each point. PCB boards should technically have a volcano shaped solder joint, but the connections to the potentiometer arms and any grounding directly on the bottom are just plain different and a shiny blob confined to a reasonably small area covering the end of the wire completely is just fine.
One last tip for any of you that are going to do the re-soldering yourself: if the grounding is done directly on the bottom of the pot and you find it falling off, it’s likely because the surface wasn’t prepared properly.
You’ll need to rough up the surface you’re going to be soldering onto – a piece of sandpaper or just scratching it up with the end of a screwdriver will work just fine.
A guitar’s electrical circuit cannot harm you, as there’s very little voltage running through. If you’re uncomfortable working with the electronic components, a local luthier or guitar repair shop can do the work quickly and cheaply.
Final Notes for Used Guitar Buyers
After the you’ve assessed the neck’s quality and tested all the electronics, you’re pretty much set to make the buy with confidence because there’s not much else that you can’t see upon general inspection. But just in case you’re wanting to build a complete checklist, I’ll leave you a few more things to consider:
Research the guitar model beforehand so you know what the original parts should be, and if you can get the manufacturing date then you might also be able to learn a bit about the issues prone to a particular area or manufacturing location for that particular model. There’s some “bad years” with a few brands, and you’ll find many more people vocalizing their displeasure for a brand’s manufacture location (people whining about Mexican made Fenders, for instance).
General wear on the finish isn’t going to be hard to spot, but the areas of focus are going to be around the strap buttons, and if it’s been played a lot, then the face of the guitar under the strings between the pickups mind have some evidence of enthusiastic picking. Some finishes will start to wear down over time simply from the warmth and friction of your hands, so run your fingers up the back of the neck and pay close attention to where the thumb would grasp the topside of the neck, as well as underneath where the other finger pads would lay.I personally don’t deal with vintage guitars, but if that’s something you’re looking to purchase, than the finish quality can definitely detract from the price and add quite a bit of hassle if you’re wanting to restore it…the job requires finesse. For me, if the rash isn’t immediately noticeable than it’s not going to be an issue unless I find a dead spot when I run my fingers up the neck. That really annoys me.
The hardware and setup should be nice and snug, if not just for the evidence of the previous owner having cared for the instrument. Try and turn the nut on the output and make sure it’s not loose, make sure all the screws on the pickup covers are there, take the back plate off and check that all the springs are there if it’s a floating tremolo, make sure the tuning heads don’t wiggle when you tune it up, check there’s no slight bends in the tuning posts from the guitar having fallen on its face at some point, flip the switches and turn/jiggle the potentiometer knobs to make sure everything installed tightly, and, finally, inspect the bridge to make sure the rivets are in place (string-through), screws are in, no rust, and the fine-tuning knobs are all there (floating bridges).
The advertising itself. Nowadays, most of the used guitar market is on the web via local advertising (Craigslist) or global bidding sites (eBay). The advertisement itself can be a red flag. Dud guitars very often will be sold “as is”. It doesn’t mean every guitar being sold as such is going to be a dud, of course, but when considering in context with the language used to describe the guitar, it does seem to be a hallmark of a person attempting to talk around the issues and avoid liability once it’s out of their hands. Ask the questions that matter most and accept only honesty – there’s a lot of turds out there, but it’s our job to protect our own interests.
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