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View Full Version : MR-03. Hot FET's


Rune
2010.02.28, 03:26 PM
I did a little practice run today, and the car was working great as usual.

I noticed the batteries were hot when I stopped, and looked over the car to see if anything was binding etc.

I then noticed the top cover was a bit crooked.
I disassembled the car and was surprised to see that the chassis was melted.
The motor lead screw was also loose.
http://lh4.ggpht.com/_2uRHE7AV3zs/S4rek_eC8jI/AAAAAAAABbY/W8O1keb7Y_E/s912/280220101495.jpg

After everything was apart I see that the chassis has melted just under the FET nearest to the chassis.
http://lh3.ggpht.com/_2uRHE7AV3zs/S4renkHeRPI/AAAAAAAABbc/OrbpPzxhC5o/s912/280220101498.jpg

I think it was the loose motor screw that did all this.

After changing chassis everything worked great again.
A lession learned: I will always solder my motor leads from now on:cool:

EMU
2010.02.28, 04:19 PM
Ive gotton into the habit of soldering my wires after frying a board at a PN regional race in PA. I was running an AnimaII, and two fets dropped off the board, and the car coasted to a stop. Board was unsalvagable with new fets. Fets didnt look fried though, it just looked like the solder melted... it was really weird.

lfisminiz
2010.02.28, 07:05 PM
Im with you guys..........since i got the 03s, i soldered all my motor wires right to the board, including my 02s.;)

Roger
2010.03.01, 01:39 AM
Same here. I just started soldering my motor leads directly to the board when I got my 03 this year.

dvsstrike
2010.03.02, 08:43 AM
are you running stock fets?and what motor are you running? i just want to know.my o3 is strickly pn 70t only.

Rune
2010.03.02, 08:45 AM
Stock FET's.
PNWC33 motor.

dvsstrike
2010.03.02, 10:58 AM
wow now i know the board caan handle a hotter motor

Roger
2010.03.02, 06:24 PM
Yeah, I was told the same thing. You can use 33 turn motors with the stock 3010 fets that come with the MR-03 boards. BUT, it'll heat up pretty quick. I just had one of my friends ( PN Racing's factory pilot: Doug Graham ) change out my 3010's to 4562's.

Rune
2010.03.03, 02:48 AM
We have been running the PNWC33 motors in about 10 different cars for over a year with the stock 3010 FET's on the MR-02 ASF, and now the MR-03. No problems on any of the cars.