The electronic bows for guitars, Ebows, are fragile: the switch has a tendency to come loose, the LED only lasts so long, and the battery leads break easily. If your Ebow breaks, you'll need to know how to take it apart to see what's wrong. The same goes for anyone who wants to modify his Ebow. They're difficult to build at home, so any DIYers after a hot-rodded Ebow are best served by dismantling a store-bought model instead of trying to build from scratch.
Taking The Ebow Apart
Open the top panel and remove the battery.
Press the flathead screwdriver's tip against the seam on the bottom of the Ebow and wiggle it in, then pop off the bottom panel.
Look under the panel, near the switch. You will see the red switchbox, held in by a metal tab. Push the switch in and pull gently on the wires to remove the box.
Open the battery compartment. Notice that the end near the switch is made of two flaps. Pull the switch box until the 9-volt lead is up against the flaps, then pry the flaps apart with your screwdriver to allow the lead through.
You will need the smallest screwdriver you can find. You may need to go around each panel with the screwdriver and pop out each edge like a paint can. Once you've popped the panels out, you can use your fingers to put them back in.
Don't attempt to replace the lead with anything other than a 9-volt connector. Don't push too hard when separating the flaps, or you may break the Ebow. If the screwdriver doesn't go in just by jiggling it, don't try to hammer or force it in. Get a smaller tool.