I've never repaired a Newton, but I have repaired several burnt capacitors in other devices.

If that is indeed what is wrong and things are as dramatic as you say there is a good chance its a simple question of opening the unit up and looking for the damaged component by either a raised top portion, or looking for burn patterns. However simply identifying the component is the easy part, actually extracting it can be more tricky especially with what is I imagine SMD components.

I suggest you take pics as you go and post them here, and then look for further insight.