I've seen a fellow racer have a brown out issue with a Tekin ESC.... he sent it in and they swapped it out with a brand new ESC for a replacement fee (I think around $75) and the new ESC still had the same brownout issue... then he realized that his radio (Spektrum) had inadvertently lost their EPA settings and went back to 100% when they were supposed to be set somewhere around 90%ish... after re-setting his EPA the brownouts went away and then came back after a few race days after his EPA's mysteriously went back to 100% again... the guy sold his Spektrum radio and never had brown outs ever again.