user16626: I have an arduino flexbot, I was making some test and accidentally I connected the battery in the opposite way. The drone turned on the six motors when I connected the battery, but any led turned on to see if the processor was working. I disconnected the battery and connected it in the wrong way again same thing happened the six motors turned on again. Then I realize that the battery was connected in a wrong way and connected it in the right way. The LED's turned on as always, and also the blue-tooth module was working I could detect the device using the control-application. I tried to fly the drone but the motors didn't turn on, I could hear little click and I saw a little movement of a motor.
I connected my drone to my PC using the micro USB connection, also I connected the battery. I tried to turn on the drone and in this way it looks to work fine.
But when I disconnect the USB port and I tried to fly it the same thing happens, the click and the little movement. Any idea of what can I do to fix this drone?

user2881: The motors turning on is expected because or the reverse diode in the mosfets driving the motor.
Looking at the schematic, it seems like the problem is on the 5v rail. If 5v isn't supplied by the USB port, it is provided by the LTC3200 (DC/DC converter)(U3 on the pcb). I think that's where the problem is, as that would explain why it only work when USB is connected.
To confirm this you'd have to measure the output voltage (pin1 (pin nearest to the ATMega) of U3, and see if it's 5 volt.
To fix it you should ideally replace this part. But it might also work without, if you simply connect the battery voltage directly to the 5v (i.e. jumper pins 1 and 5).

16626: <p>I have an arduino <a href="http://www.flexbot.cc/" rel="nofollow">flexbot</a>, I was making some test and accidentally I connected the battery in the opposite way. The drone turned on the six motors when I connected the battery, but any led turned on to see if the processor was working. I disconnected the battery and connected it in the wrong way again same thing happened the six motors turned on again. Then I realize that the battery was connected in a wrong way and connected it in the right way. The LED's turned on as always, and also the blue-tooth module was working I could detect the device using the control-application. I tried to fly the drone but the motors didn't turn on, I could hear little click and I saw a little movement of a motor.</p>

<p>I connected my drone to my PC using the micro USB connection, also I connected the battery. I tried to turn on the drone and in this way it looks to work fine.</p>

<p>But when I disconnect the USB port and I tried to fly it the same thing happens, the click and the little movement. Any idea of what can I do to fix this drone?</p>
 2881: <p>The motors turning on is expected because or the reverse diode in the mosfets driving the motor.</p>

<p>Looking at the schematic, it seems like the problem is on the 5v rail. If 5v isn't supplied by the USB port, it is provided by the LTC3200 (DC/DC converter)(U3 on the pcb). I think that's where the problem is, as that would explain why it only work when USB is connected.</p>

<p>To confirm this you'd have to measure the output voltage (pin1 (pin nearest to the ATMega) of U3, and see if it's 5 volt.</p>

<p>To fix it you should ideally replace this part. But it might also work without, if you simply connect the battery voltage directly to the 5v (i.e. jumper pins 1 and 5).</p>
