Thanks for all the information and advice. I'm happy to report one more m100 is working.
Two of the caps I had replaced c82 and c85 had leaked, damaging the circuit board on top. I didn't notice it during my recap, lesson learned to look more carefully next time. Underneath c82 was a small trace that runs to the contrast control. Once I cleaned up the leak damage and patched the trace, the screen came back to life. I chased down some dead ends while debugging, but learned a bunch in the process. That was kind of fun!
