Here we see one of the leads has become disconnected from the input jack terminal. As you can see, the terminal has solder. This needs to removed and replaced with fresh solder as to avoid a cold solder joint.
Step 1: Applying Fresh Solder
Using my helping hands, I position the end of the lead so I may apply solder to the tip. The old solder on the terminal has been removed and new solder will be added there as well.
At this point we also want to slide a piece of heat shrink tubing onto the lead so we can insulate the finished joint.
Step 2: Successful Solder Joint
As you can see the joint is nice and shiny, signifying that the joint is solid and is allowing a strong connection. This is important for the tone of the instrument.
Step 3: Insulating Using Heat Shrink Tubing
Here I used a piece of 11/64" heat shrink tubing. Now that the joint is secured I slide the tubing back down the lead and over the joint.
Using the soldering iron I carefully apply heat to shrink the tubing tight around the joint. Be careful not to burn the tubing!
Step 4: Finished!
You can see the tubing is tightly wrapped around the joint to provide good insulation. All there is to do now is screw everything back in, plug in and jam!