Phantom 3 Std. Motherboard/ESC failure on power-on - Please Help

How do you know the supposed failed 0603 part is a capacitor vs. a resistor if unmarked? I only have the schematic for the older P2V+ ESC, though probably quite similar to the newer Phantoms. Only so many ways to get those motors to spin. The MOSFETs gets its drive pulses from a microprocessor controller chip, which in turn energizes the motor windings in sequence. Only resistors in that circuit for setting the MOSFET gate drive levels and voltage sensing (to verify the motors are spinning). Only a few 0.1uf and 1.0uF capacitors on the voltage bus and a voltage regulator output. If you have any electronic skills at all, I would recommend seeing where the failed device traces goes to. Probably to one of the MOSFET ICs. Knowing the pin number and markings on the MOSFET chip could help determine its function. A spark in unsettling. As others have said, that would be caused by a short further down the line (like the motors or wiring), or perhaps that component wasn't soldered correctly on one side making it spark when you applied the heavy load of the motors. Capacitors on the ESC are used primarily for smoothing out the DC voltage on the battery buss from the motor pulses. I would unsolder that component in the event it is shorted out and carefully power it up again. If a failed capacitor, that should not effect how the motors are driven. If a failed resistor, it would alter the gate bias on ONE of the MOSFETs, making ONE of the motors spin with a hiccup. The only real way to know if the motors are getting the proper drive pulses, proper voltage and sequence is to use an oscilloscope. A DVM won't tell you much unless one of the three wires is zero volts. Good luck and let us know what you find.

I googled '0603' capacitor. I'm no expert, but it would make sense to me from my experience working with those little things that they would be capacitors. From your explanation, you may be right but I still don't know why everyone else I've seen calls it a capacitor and why it looks like one.

My experience with electronics is fairly limited. I tried to trace the traces from that blown capacitor/resistor and didn't have much luck. At this point, i've already gotten the drone back up and flying with the new internals, even though it still cost me a bit of money. I'm not going to put that old board back in the drone, but i'd still be interested in fixing it, or at least donating it to the cause of research, if not by my own hands, maybe someone else wants to give it a try.

I did remove the component and I sorta kinda 're-tinned' what remained of the pads (since they kinda got blown apart). I was curious about powering on the drone, and I still could, but I won't have a camera to use and I'm not pulling the one off my drone. I don't need to see the whole thing running and all, but I could at least hear the beep and see the LEDs on and motors twitching, right? (or at least 3 of them) Thoughts? It's worth a try, what do I have to lose? I've got tons of spare parts now XD

Thanks for the continued support as always!
-Benji
 
I googled '0603' capacitor. I'm no expert, but it would make sense to me from my experience working with those little things that they would be capacitors. From your explanation, you may be right but I still don't know why everyone else I've seen calls it a capacitor and why it looks like one.

My experience with electronics is fairly limited. I tried to trace the traces from that blown capacitor/resistor and didn't have much luck. At this point, i've already gotten the drone back up and flying with the new internals, even though it still cost me a bit of money. I'm not going to put that old board back in the drone, but i'd still be interested in fixing it, or at least donating it to the cause of research, if not by my own hands, maybe someone else wants to give it a try.

I did remove the component and I sorta kinda 're-tinned' what remained of the pads (since they kinda got blown apart). I was curious about powering on the drone, and I still could, but I won't have a camera to use and I'm not pulling the one off my drone. I don't need to see the whole thing running and all, but I could at least hear the beep and see the LEDs on and motors twitching, right? (or at least 3 of them) Thoughts? It's worth a try, what do I have to lose? I've got tons of spare parts now XD

Thanks for the continued support as always!
-Benji
Just put it aside Incase you need it for what ever reason. It’s not worth much the way it is, unless in your case, someone needs a part.
 
Just put it aside Incase you need it for what ever reason. It’s not worth much the way it is, unless in your case, someone needs a part.
Yeah, that's a fair plan. I wasn't expecting to get much from it in terms of resale value, so I'll keep it around.
If anybody needs photos, part numbers, parts, measurements etc. from one of these types of boards, please let me know. I'll be happy to provide!

It's a P01103.06 Model if anyone is curious.

-Benji
 
Glad you got your drone working and flying with the new board.

The main DJI board is built by machine. The components are on long strips of paper wound on reels for machine assembly. The machine places the components where they belong, kind of stuck in place by a glue, then heated to "sweat solder" the components in place. Seldom are reel components marked to know what they are, and seldom does this technique cause soldering problems - but can happen. 0603 capacitors and resistors can look virtually identical.

The fact you checked it with a DVM and the resistance kept changing does suggest it was a capacitor. You were likely watching the resistance change as the capacitor charged up from the small voltage on the DVM probes. And good job with your soldering skills and attempting to trace the circuit and swapping out the board. You are to be commended for attempting these things, and you probably learned more than you think.

If it's flying, leave it alone and enjoy it. As as often said, "If it ain't broke, don't fix it." Again, good job getting it fixed and flying.
 
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Glad you got your drone working and flying with the new board.

The main DJI board is built by machine. The components are on long strips of paper wound on reels for machine assembly. The machine places the components where they belong, kind of stuck in place by a glue, then heated to "sweat solder" the components in place. Seldom are reel components marked to know what they are, and seldom does this technique cause soldering problems - but can happen. 0603 capacitors and resistors can look virtually identical.

The fact you checked it with a DVM and the resistance kept changing does suggest it was a capacitor. You were likely watching the resistance change as the capacitor charged up from the small voltage on the DVM probes. And good job with your soldering skills and attempting to trace the circuit and swapping out the board. You are to be commended for attempting these things, and you probably learned more than you think.

If it's flying, leave it alone and enjoy it. As as often said, "If it ain't broke, don't fix it." Again, good job getting it fixed and flying.
NW_Quad - Thank you! You summed up my thoughts perfectly actually. I'm enjoying having the use of my Quad again, even though the weather is less than great where I live.

And, what you said makes sense. I don't have a replacement part and i'm in no hurry to do anything with this board. I can keep experimenting and maybe someday the board will work. However, I'm aware of how these kinds of boards are made (as you explained), and the fact that that component could be quite a few things other than a capacitor. The multi-meter fluctuation makes total sense though - I was very confused by that when I was testing it. We'll see though, if anybody has any more suggestions, I would be happy to do more testing for the fun of it. This has turned into a rather pleasant project actually.

-Benji
 

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