Yeah, it was a simple one because of the design. What they did was to have a separate PCB board for the three LEDs. And when I looked at it, it was just a simple resistor and LED network. Then again, this toy uses only two AAA batteries, which means, at 3 volts, there is not much power to play with.
Stage 1 Modification
So, the first modification, which I call it as Stage 1, was to change the yellow LEDs into White LEDs. You can use either 3mm or 5mm versions but beware on the shades of white. Some tend to shift towards yellow, while others go to blue.
Advanced Stage Modification
I took the idea further because I was not too thrilled with only three white LEDs. I wanted more LEDs and not necessarily more brightness. I want the Arc to look as if it was a continuation from the first movie. This modification took a lot of time because of the methods I used. But the end result was worth it.
After talking with Peter, I finally found the solution to where he and Richard (from The Outpost) requested the Arc to have the lights on and off at will and not follow the 'sound'. And the solution (in my opinion) must not have any visible switches. Do you have the solution? If not, wait for a few days as I need to find/buy an electronics component.....