Ryan, I suggest reading this and many of these questions will be answered for you. http://mitatechs.org/faq
The newer keyboards are like computers, very specialized internals with parts available from the OEM only as long as they are willing to supply them...typically no more than 10 years...often less than this.
I get these same calls you do. If its not out of my way and I can schedule it in I will often drop by and try and help. I'm succesful about 30% of the time and the only reason for that is that its either an external or internal in line fuse blown. You need to figure out how to dissasemble some cabinet parts and do simple testing with a multi tester. These keyboards are very susceptable to power surges and spikes off the grid if not protected well with a quality surge protector. The organ work in churches and such and tubed older equipment is a whole thing in itself...MITA can help with this if your willing to give up a week to travel to Vegas for one of their specialized classes.
There arn't a lot of these techs out there. We have about 3 or 4 here that cover a population area of several million people.