OK need help from the more experienced people. This just started over the weekend, everytime I plug my battery into my Corona 120 the blade begins to spin. Take it from me, it hurts like heck when you get hit in the hand on a cold day and you weren't expecting it. I've checked and re-checked all the controls on the remote, no throttle hold, no nothing that should be giving it power, and nothing has changed since my last flight. Only thing I can think of is the ESC is going out. Would an ESC cause this issue and would it just flake out like that all of a sudden?

Thanks
Chris

If the transistors in the ESC are shorted it definitely will cause the problem you describe. Under no circumstances should the motor start when you plug in the battery since all modern ESC's use some type of arming sequence before the motor will run. In fact I had the opposite problem with my ESC. It wouldn't always work which which was solved by extending the end points of the throttle channel slightly. It wouldn't always arm.

If your motor starts as soon as the battery is plugged in you need a new ESC. The way to check this is take an ohmeter and check the resistance between the input (battery) side and the output (motor) side. There probably will be continuity between one terminal of the input and one terminal of the motor side, usually the negative side. The other side however will go through the power transistor and should not have continuity. If it does the ESC is bad.

Regards,

Mike

Thanks, I tested it and sure enough I get continuity on both lines (+ and -) so looks like a new ESC is in order. Any recommendations ?

If its a CC (castle creation) ESC, you can send it back to them and they will repair or replace it. The last I checked, its been a while but I think the service charge is $25 repair or replace. Not really a bad deal. I had the same problem and I called them and thats what they told me. I got the number from LiteMachines.