Originally Posted by ironhorse99
After about one min it start to lose altitude, not crash, just slowly set down.
In my experience its the motors almost without a doubt. This has happened to me several times with the most recent one just this week.(10-12-12) As I have a brand new 1300 mah/30c battery installed I knew it was the motor. If you look into the vent holes you'll notice that 1 brush is almost completely gone. I use hat style magnifier with a light to check the brush status. With 3x daily flights I get 2 weeks out of a motor which is why I'm going with the xtreme pro 180A. This motor allows for easy brush replacement & @ $1.25 a pop its worth the investment(at least for me) You can find the carbon model here: http://bit.ly/ToCN3J
This brush set offers a little less torque but 30% more run time. They also sell the silver models which don't last as long. BTW you get 2 pair for $2.70 which is a steal.
Yes, it's the motor worn out.
replacement of stock is 3.87$ shipped if you buy three at banggood.
When replacing the stock with a xtreme pro 180A you also have to change the tail motor. Stock can't hold the upgrade. It's been reported that you can use the MJX F45 tail-motor plug and play.
If you'll like it or not - your decision - I would stay with stock anyway.