Scott, I'm sorry you had to be without your Tyros for such a long time.
Hopefully, Yamaha will get the hardware right (and 99% of the software) the first time - next time they make a high end keyboard.
I have had relatively good experiences with my local repair facility. I wish it were more local. I have to pay $25 to get it done in a week. I can have the repair done in three to four weeks at no extra charge.
I once had a blown speaker on a PSR2000. They replaced it within a week (easy repair).
I once had a PSR740 go out on me completely. They replaced the motherboard within a week. Worked fine.
I once cracked the plastic or glass cover of the LCD on my PSR2000. As they keyboard worked fine, I just asked for it to be ordered before I had it installed. I waited 3 months, and the repair facility told me Yamaha never sent them the part. I don't know if the repair facility was flaking on me. I contacted the head of Yamaha repair, and they Fedexed me the part within a week. I had a friend install it for $30.
I hope, Scott, that you get your Tyros back soon. A musician shouldn't have to be parted from his keyboard.
Beakybird