Lyens sells a good one, look him up in the for sale new, and contact him.
Similar if not identical ones on ebay, but might not ship from the USA like from Lyens.
A few tests are easy. Shorted phases indicate by excess resistance to turning. Unplug your phase plug and the problem goes away, then it's shorted at the controller.
First step of any troubleshoot, find that cut wire or unplugged wire. 90% of the time that's it on my bikes, one wire backing out of the plug housing.