Serious Damage

[KaR]V[aN]

Hi all,

I've already mount my 10DOF crazyflie (got it 3 weeks ago) and I'm very happy, this has become my new favorite toy since my last microwalkera since this tiny quadcopter is far more agile.

The thing is some friend ask me to buy him one and mount it for him. Seems that I overheated (somehow..) the M3 pads and Q3 is now sorted. The moment I plug the battery the M3 goes crazy even with the crazyflie 'shut off'. When tested with multimeter, source and drain are sorted. The diagnose is clear, I need to replace Q3.

I'm not some surface mounting expert soldering but I can manage with wires. Surface is clean to solder the motor and the other 3 motors pads among my own crazyflie is pretty much clean soldered (really, I don't know what happened with M3 in this 6DOF). The thing is I need to replace Q3 the best way I can. I've already bought the PMV31XN part from ebay but I would like to take some advices from you guys about how to properly unsolder the burnt Q3 to left the surface as clean as possible without damaging Q3 pads so soldering the new one would be as easy as possible.

Thank you.

[tobias]

If you have a pair of nippers or small wire cutter you can cut away each leg on the PMV31XN since it damaged anyway. Then it is easy to remove the leg bits that are left without damaging the pads. Then you can clean the pads with some solder wick, and solder back the replacement leg by leg. If you have some scrap electronics you can try and find a similar package to practice on first.

[KaR]V[aN]

This is becoming weird.

I followed your advice (also said what I though to do) and managed to repair the crazyflie by replacing the dead mosfet.

Motor test over the bench went fine, and it was flying nicely as new until a small crash, one of those like from ground to the inferior part of a chair and the M3 arm broke badly.

I though it was weird since I've been flying my 10DOF about a month and I haven't broke even a propeller despite some serious crashes...

When I was assembling this second kit (6DOF) I noticed some looseness between the M3 and M1 plastic holders and the arms, but M2 and M4 fit perfectly (that is, with a light pressure, just like my 10DOF). I had to fix it with a small paper wedge to ensure that M1 and M3 plastic holders won't move:

http://i.imgur.com/WdoX74R.jpg

Also, inspecting the board carefully on both sides you can see the surface semiconductors being weirdly soldered, with random blobs everywhere:

http://i.imgur.com/SlO5hGw.jpg

http://i.imgur.com/IoXpUyT.jpg

I've compared the board with my 10DOF and I would swear they aren't from the same factory (although probably they are..).

Do you guys have the same blobs on your crazyflies? Could it be a defective batch?

I'm really worried because, even I'm aware about how fragile is the crazyflie but this is more likely a curse over this one :S

[EDIT] Could it be possible to buy just the board? [/EDIT]

[tobias]

Let's try to arrange something. I've sent you a PM.