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Tech How-to: Fixing a Scratchy Guitar Input Jack in 10 Seconds

Hello, friends, devoted visitors, and new readers. This tech how-to covers one possible solution for fixing a scratchy input jack on a vintage guitar. The "TL;DR" YouTube version is down below.

We won't get into the nuances of the definition here but, for the sake of simplicity, let's just call a "vintage guitar" one that's been around long enough for the metal on it to tarnish and oxidize.

Over time, one of my "vintage" guitars - an early 2000s Ernie Ball Music Man StingRay bass - slowly developed a bad connection, causing popping and crackling to come from the amp. I first confirmed the cables were't the problem. These basses have active (aka powered) pickups, so I swapped out the 9V battery - that didn't help. I pulled out the input jack and bent the prongs around, thinking maybe, somehow, the guitar cable just wasn't making solid contact with the bass anymore. That wasn't the solution. In retrospect, it shouldn't have been, either... Unless you're a time traveler, playing guitar for Nine Inch Nails in the '90s, there's hardly a reason the prongs inside the instrument should get bent up. I was just trying something, and that didn't work.

Still searching for a fix, it seemed like a new input jack would be the final answer. I called one of the nearby Guitar Center stores, to see if they had one in stock that's compatible with Music Man basses. After a brief time on hold, the eager young man picked back up and reported to me, "Yeah, we have some input jacks in stock." "But will they work for active pickups?" "Umm, I'm not sure. What's the difference?" It's an important distinction, and I'm truly glad he asked. Because of the connection to the battery, guitars/basses like mine originally had four prongs on the input jack, as opposed to just two that connect to standard, passive guitar pickups.

With the Music Man jack being a speciality part, the Guitar Center guys didn't know what to order, so I contacted Ernie Ball. Using my guitar's serial number, they were able to give me the exact part number for Guitar Center to request. They also sent wiring schematics, since the part has been redesigned - it now has three prongs instead of four.

The special order was only a few bucks, with the modest shipping and handling charge being about as much as the part itself. I really don't like soldering so, when that arrived, I called up my local guitar repair guy. He sets up instruments for John Mayer, Red Hot Chili Peppers, etc., so he definitely knows what he's doing... and I figured the job would be quick.

In his workshop, it seemed like he really didn't want to solder, either. He took a close look at the nearly-pristine, 20+ years old bass, studied me for a moment, then said "Let's try something else first." He wrapped a little sliver of fine grit sandpaper around a thin screwdriver, then gently worked the sandpaper around against the contacts of the input jack for a few seconds.

He sprayed a puff of compressed air into the jack, plugged in the bass, and wiggled the guitar cable around. No scratches or pops! That was really easy! Then he charged me $20.

If gently working around the sandpaper in the guitar jack for a few seconds doesn't clean off some oxidation and dust and fix/improve a bad connection, the problem is likely something else... but this is a great place to start, using just two basic tools that many of us already have at home.


Here's the video tutorial:


"Tech How-to: Fixing a Scratchy Guitar Input Jack in 10 Seconds"

Written by Justin Kilmer

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