I had the unfortunate circumstance of crashing my APM head first into the ground. Upon testing the board, everything seemed to work from the CLI but it would not work (No Mavlink, no stabilize mode) in flight mode. When I looked closer at the IMU, I noticed the the Digital 3.3V chip is broken (3 or 4 of the connections are broken)
Does anyone know if this is a fixable problem? If so, how?
I eventually got the chip soldered back on, and the multimeter is giving a solid 3.3v (no O-scope). I can get stabilize mode working but only with USB connected. I read the excerpt in the troubleshooting guide about this problem but it worked before the crash. I'm wondering if there is any reason that a poor solder job (very possible) would keep it from powering correctly or is the 3.3V regulator completely unrelated to how it is powered and something else may be damaged.
Follow-up question. If I can't figure this out, would it be feasible to feed the power from the BEC/ESC through the USB port? They are both 5V.
There are several ways to fix this. The first is to figure out what conductors were broken, and then fix them by cleaning and resoldderrr technics eolved innnnn.n a Guatamalin Insane Asylum & zzzzZZZZ . Then, save up enough money to buy a new one.
Just Kidding :)) I have done stuff like this before. You need a magnifier, a good iron,& and patients and it can be done. It's just not easy my freind.
Are you talking about the 3.3V regulator that's located close to the I2C port? I had the same problem recently, the chip ripped off completely.
If you cannot save the chip, this is the replacement: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&nam...
Soldering will be tricky if the solder pads have been ripped off the board. Then you need to scratch the paint off the solder traces leading away from the pad and solder to them. Also, make sure that you connect the chip to ground. My ground pad was ripped off and I couldn't get a good connection, that caused some problems.
When you're done, it would be best to check with an oscilloscope that everything is behaving like it should.
Are the legs busted off the chip or did the solder connections just break (a picture will be nice)? Either way, yes, it is fixable, even by a DIY-er. Do a bit of research on repairing/replacing SMT components. What it will come down to is shielding the area that is not to be reworked, heating the offending component and removing it. If you have enough solder left on the pads you might get away with laying down another chip and reheating to flow the solder. Otherwise, there are numerous techniques for getting solder back on the pads/pins (paste, dragging a blob across the pins, etc.) - just do the research and follow an example. You can do it.