View Full Version : Blown reverse FETs ... not sure why.

2010.04.03, 09:48 PM
I got my first 2.4ghz car today. I set my controller per KO PROPO recommendations, paired the car to the transmitter and put it on the track. Worked great. Ran the car till the batteries died down. Shut off everything and put a new set in. I noticed one of the motor caps sticking straight out from the motor and pushed it down. I put it back on the track and only had steering. So I tightened the motor leads and tried again. This time I got smoke. So I shut it off quick. I checked to make sure the motor leads weren't touching the cap/diode deal in between the positive and negative leads and powered it back on. I have full power forward but, reverse doesn't work. It actually rotates the motor forward slowly and starts smoking the FET on the left. Both the top and bottom FET have bubbles. So I'm guessing I blew the reverse FETs. I would like to know how. When I pushed the motor cap down and out of the way did I short it? I can't figure out what I did. I really don't want this to happen again. So any insight would be nice.




Action B
2010.04.04, 10:06 AM
A guy at a local track burned his reverse FETs twice yesterday.

We determined the cause to be the motor he had tweaked must have had a problem. I know you didn't tweak yours but I wouldn't be sure that motor doesn't have an issue. Correlation does not necessarily imply causation.

Anyhow, if you need them replaced you can PM me and I'll get your car fixed up.

2010.04.04, 02:19 PM
Yeah I was thinking it might have been the motor as well. Wish I could tell somehow if it was the motor. It looks new. I'll take the brushes out of it today and break in the bushings and clean the comm.