I bought 2 in the last month and they both failed before getting to the track. The first one set up fine and then when I pulled the trigger the motor ran slowly and the speed controller got very hot. This was without a pinion connected. I had another Novak motor that I knew worked so connected that up and same problem so definitely the controller.
The second one set up okay and motor ran without the pinion then came back to it last night to get ready for the weekend plugged a battery in and the speed controller started sparking and one of the legs of the cap burnt through like a fuse battery also got very hot. I know it isn't a problem with the battery as I plugged it back into the B4 and it worked fine. So that is 2 from 2
I have been racing for 20 years adnd in all that time have only had one other controller fail due to manufacturing defect so either I am very unlucky or there is a bad batch out there.
Worst part is I bought the controllers from an online store in the US and I live in Australia so I went to the Novak website to find out where to send them for warranty and the site says no warranty on units purchased in the US if you don't live in the US