I bought the Tron Legacy Deluxe Identity Disc for around £20 from eBay. It’s not really as exciting as the Tron disc in Tron Legacy; out of the box, the on switch starts a pretty unimpressive sequence of LEDs lighting up sections of the disc. (There’s another button to activate a sound that’s supposed to be somehow related to the film but to me sounds pretty naf so ignore it.)
I wanted a Tron disc with lights that remained on.
I followed this tutorial which showed how to open up the disc and modify it so that the lights stay continuously on. You need a small Phillips screwdriver, a soldering iron, some solder and some thin electrical wire. Unscrew the six screws on the back of your Tron disc and gently lift off the back plate. You should now see the chip which controls the sequence.
Here’s the science bit: connect pins R3, R4, R5, R8, R9 and R10 to the battery in series. That’s it.