Fishing a volume control out of a semi-hollowbody for soldering.

Issue 94 August 20, 2009

Hey! It's crowded in here!

Erick looking through f-hole

Wiring repair: how to work on the electronics inside a semi-hollowbody

The bridge pickup isn’t working on this guitar.

And I think this volume control is why.

The volume pot for that pickup is loose, so when you turn the knob, the control pot inside turns along with it.

When the knob turns, so does the pot inside

Spinning control pot

The guitar’s owner says it’s been this way for quite awhile. That explains the dead pickup: the back-and-forth twisting must've snapped the soldered connections on the pot or shorted the wires by touching them together.

I’ll use an inspection mirror to take a look inside.

Inspect mirror

Here’s the kind of problem in there: a wire has broken off one of the contact lugs on the volume pot. That explains the dead bridge pickup. The ground wire’s broken loose from the pot case, too.

Broken solder joints

So I’ve got three things to do:

  1. Resolder these connections.
  2. Tighten up the pot so the shaft won’t spin anymore.
  3. Do all of this work through the f-hole of the guitar! ($&@#%!)

I mean, take a look at the complex wiring harness that fits into a guitar like this. When you’ve got to pull all this out and put it back in, the best way is through the bridge pickup cavity — and that is really time consuming!

Wiring harness

There has to be an easier way!

Check It Out!

Jack The Gripper

It's no fun to watch the jack disappear into your guitar or amp as the nut falls off. This ingenious tool grips inside the jack to hold it steady while you adjust the nut.

Jack the Gripper

Lucky for me, this volume control is close to the f-hole. There’s a good chance I can access the pot through the f-hole instead. I carefully pulled the knob off.

Knob puller

My secret weapon: rubber bands looped end-to-end.

Rubber bands

They go on the shaft before I drop the pot into the guitar body.

Rubber bands in use

With some felt to protect the guitar, a pair of hemostats pull the pot out. (Don't let the other end of the rubber band slip into the guitar!)

Rubber bands in use zoomed out

With some felt to protect the guitar, a pair of hemostats pull the pot out. (Don't let the other end of the rubber band slip into the guitar!)

Removing the volume pot

A piece of cardboard supports the pot over the f-hole while I resolder the connections.

Soldering the volume pot

The pot goes back in through the f-hole, and the rubber bands pull it back into position (below). Then the washer and nut slide down the rubber bands onto the pot shaft, and I make the nut finger-tight.

Rubber bands back in position

I tighten the nut once and for all with the spanner wrench. This is the time to check the other pots too and the jack, making sure they’re good and tight.

ESP spanner wrench

All done and ready to go. This job was quick and painless!

All done!

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