Hopefully this helps anyone with a B200 error. I have a Pro-10 that started flashing alternating between the power and fault LEDs, 10 times per LED per sequence. Totally unresponsive to anything I did, has all Canon pigment installed and only Canon pigment has ever been installed. Tried unplugging power, restarting numerous times, nothing. I even tried someone's suggestion to unplug power, hold power button 30 seconds, reconnect AC power, still didn't work.
Here's what solved it for me-
I unplugged the unit, held the power button down for at least 30 seconds (was probably about a minute), while >STILL HOLDING THE POWER BUTTON DOWN< plugged the unit back in and kept holding the power button down for at least another 30 seconds (while doing this the power LED was solid white the entire time) then while still holding down the power button also pressed and held the feed button for at least another 30 seconds (holding down both). Upon releasing the two buttons the printer appeared to be off (another time I performed this for a customer on his Pro-10, upon releasing the two buttons the amber feel light was on solid and it worked that time as well).
I then unplugged the power, plugged back in, turned the printer back on and, lo and behold, it started up and performed a lengthy self clean cycle and functioned as normal.
Hope this helps someone, may work on the Pro-100, Pro-9000, Pro-9500 and perhaps other Canon pronters as well.
To recap, unplug, hold power button 30 seconds unplugged, plug in still holding power button, 30 seconds, while still holding power also hold feed button, hold both another 30 seconds, release, unplug unit, plug back in, power button to turn on, profit (hopefully!).