Yamaha DGX 205 A and Eb keys not working?

[storyfromthestars]

I have a Yamaha dgx-205. I haven't played it in a while due to a busy schedule, but am finding that my A and Eb keys (in every octave) will not play. They are the only keys that don't work. A friend mentioned that to me a few months ago when he played with it, but I'd never noticed the problem before. It's been transported a lot, but has never taken any major damage, bumps, knockings, etc and has no visible damage. The last time I played it, it worked perfectly fine. Would it be a simple wiring problem, or do I need to get a new keyboard?