I contacted Graber yesterday. They said the CPU is shot. It's just over a year old, so they wont warranty it. When I asked if I could order a new one and if I could have it overnighted, they told me to just go to my local bike shop and have them deal with it.
I've had a lot of problems with my powertap. 14 months of use, 4 wiring harnesses, this will be my third CPU, and I just had to have the torque tube replaced, which took over a month, although I was told it would be done in a week.
This latest encounter was different in that they pretty much gave me the "FU - go deal with it on your own" feeling. All the other problems I've had were at least mitigated by excellent customer service. Looks like that just came an abrupt halt.