After a lot of testing the battery in the disc runs out. It uses 6 little watch batteries which aren’t easy to replace. I wanted to wear this costume out, and if I ran out of batteries, I wanted to be able to go to the nearest shop and buy batteries to stick into the disc, without having to open it up with a screwdriver.
The only place to fit a 9V batttery is at the top end of the disc. This is where the break in the inner “C” ring of the disc is. Currently that’s where the speaker and sound chip are stored. The 9V battery will not fit completely into the disc but will stick out discreetly. Open up your Tron disc again and cut out the speaker and the chip it’s attached to. Tape up exposed wires. Now heat a screwdriver tip or a sharp knife over a candle, and cut away the plastic that held the speaker and chip. You will also need to cut a small way into the disc rim on both halves of the disc. Make sure you only cut away a hole that in the end makes a tight fit for the 9V battery.
Next, unscrew the battery door, remove the original 6x watch batteries and replace the battery door. Now open up the disc and disconnect the wire we ran from the circuit board to the battery neg line, and instead connect it to the battery neg line on the 9V battery clip. Next, connect the battery clip’s pos line to the disc’s original battery pos line. Run the battery clip wires neatly along the disc down to where the 9V battery will slot in. I used a lot of electrical insulation tape to cover up exposed wires.
Attach a 9V battery to the battery clip, tape it up so it’s black, and test. You’ll find your Tron disc now shines about twice as bright as it did with the original watch batteries. Close the disc and push the taped up battery in. You may have to cut a little more around the disc rim in order to get the battery to fit perfectly.
Note: You will now have to make a small notch on the battery disc holder so that the disc fits on with the battery protruding out of it.