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View Full Version : Horribly wrong


Chris M
2011.05.01, 12:57 AM
Two days ago I got the build done. I took it for a spin around the kitchen and the thing was scooting!

I went to a HFAY track today and put in a set of batteries. Hit the throttle and it moved at about 1/2 a mph and only for about 5 feet. Then I smelled it. Something was burned up in the car. I haven't had a chance to pull anything apart but something is fried!

I think the car is toast and the board screwed the pooch.

Has anyone heard about this happening on MR-03's?

Edit:
I put the stock motor back in and I think I may have torched the FET. it spools up the stock motor VERY slowly in forward and goes SUPER hard in reverse just like it was before. Could the motor I have in the car have burned up the FET and if so will this cost me a ton to replace? When I ordered the motor I asked for a stock replacment but a different brand so I could bolt it to my LCG PN MM mount...

THe Motor I have in the car is a CTP motors 70.

color01
2011.05.01, 06:20 AM
Grab some pics of the board -- although it sounds like you've fried something, if the stock motor still spools forward then you haven't completely killed the FET yet. Generally the board traces are harder to fry than the stock FETs, so let's see some pics and that will help us diagnose what went wrong for sure. :)

arch2b
2011.05.01, 09:54 AM
i've bought 3 mr-03's and all of them fried throttle fets within 15 minutes on the track for the first time. i don't bother anymore and get them replaced immediately.

just find a qualified person to replace the fets and you should be good. need pictures as suggested to see how bad the damage is.

chad508
2011.05.01, 10:11 AM
one thing i have found is you must breaking new motors before running them in the car. i feel the new motors arc to much causing things like this to happen. other problems are steering glitches. as far as the motor you used it is great motor but i have found it needs a lot of break in time to keep it from arcing. out of the 4 mr03 i have i have had one board completely fry and 2 others just fried the fets. the one that completely burnt up was on a new hand out motor at a race, it had been running fine with my motors but as soon as i hit the trigger it went up in smoke.

arch2b
2011.05.01, 11:21 AM
i've been hearing of issues with the CPT 70t motor. there were some issues at the capitol challenge with this motor as well. the motor runs great for me, no problems at all, but others have not been so lucky. the question then is, what is it about this specific motor that is causing this to occur? i've seen stock motors burn fets but it's rare. it's not coincidence when it happens with the rate of frequency it has for a new to market motor.

repalce the fets:p rather cheap fix thankfully. not like it was 5-10 years ago when it cost $25-50 to get it done.

chad508
2011.05.01, 01:12 PM
from what i remember at the capital challenge a lot were having problems but they mostly all went away after a few runs. i broke my motor in for over an hour and had no problems at all.

Chris M
2011.05.01, 07:28 PM
Thanks for the replies. I was sure that the FET's were the problem but not having dealt with this before I was worried it was something more. I'll be sending the car to Atomicmods.com for a FET stack. We'll see if she works better that way. I have an old motor break in station. I'll see if the thing still works.

I'll post up results.

cowboysir
2011.05.01, 07:43 PM
not tryimg to take anyones busness but trey cintacting action B here on the forum for fet work.;)

Mike Keely
2011.06.09, 10:36 PM
I agree, Action B is who you should get to install your fets. Much lower cost and much faster also. Just my 2 cents.:)

pzchuky
2011.06.10, 09:01 AM
Action did my board and he fixed it and stacked the fets for cheap.

i will be sending more of my boards if they need repairs to him.