We have had strange problems, the solution was where the transmitter mixing caused improper ESC signals on power up.
In some cases it sent the ESC into program mode, so by the time we lowered the throttle level we now had a non-functioning ESC. Also the default parameters don't seem to be the same as a virgin ESC.
Bought 5 of these and one by one they quit working. I knew I had not damaged them so I took A LOT of time to figure them out. The problem is if you power up your ESC with the throttle NOT all the way down, you can start the programming sequence. (Same as the HK blue ESC's) The first in the series (called AAAA) is just 4 simple beeps, 2 seconds after power up.... WELL when you finally zero your throttle, you will have changed some parameter, depending on where you are in the programming list.--TIME TO GET THE MANUAL AND FOLLOW this (see FILES TAB). So this problem is fixed by going through the programming sequence until you get to the "default parameter" and then lower the throttle all the way. PS: A program-card is a good investment!
BUT-T ----- Then the last problem: if you make the throttle-up mistake and lower the throttle after the first 4 beeps, that is the throttle-calibration, (not reset like the parameters). A couple of mine got so out of wack I had to use a pulse generator that could go longer than the 2 millisec max speed pulse a transmitter puts out ... and work my way back in the range. This shows up because you get the arm-tone (3 beeps for 3 cell lipo and a slur-up note) yet the motor will not run. When this happens you can get this arm-tone even when you are mostly full throttle. The arm tone is put out when it thinks it is at min throttle. End of the story - all 5 work again!