PM07 boards gets heated a lot in one corner and smells burned

Hi everybody,

I’ve been flying drones for a while now and recently started into building my own.
I buigt a Durandal with PM07 to build into one of my existing drones.

After soldering and wiring the PM07 and measuring that i made no short circuits everything seemed fine.
If i connect the battery all motors are able to spin, but i smelled a vaque burning smell.
After some research i found that one corner of the bord (The M1 connection corner) is way hotter than all others. I desoldered the wires in that corner, and measured again to make sure no short circuit. Still when powering just the bort with nothing connected that one corner gets really hot. I did not measure the temperature but it did burn my finger slightly…

Any ideas what i might be doing wrong?

Kind regards,

I’m afraid I can only suggest unsoldering everything and connecting power. If with nothing connected to the board except power, it is still getting hot, there must be a fault on the board. Check again for solder bridges between pads. Unfortunately it’s going to be hard to prove to asupplier that you didn’t damage it so I fear you may be out of luck unless they are a particularly helpful supplier. If it’s faulty you will need to unsolder it all anyway! :frowning:

If it doesn’t get hot with everything else unsoldered, I’d start measuring the resistance of each component connected across the power. Be aware that ESC capacitors cause high current to flow initially before showing steady state resistance. This can look like a short circuit for a few seconds to a multimeter.

Good luck!

Thanks for the reply. I tested and with everything unsoldered and disconnected it still gets hot. After a carefull look and longer connection to the battery for testing some smoke starte to appear, so i’m kinda sure it is something in the board. Contacting the supplier without much hope but who knows.

Going to try again with a new one and hope it works out then.

Also thx for the tip with the ESC capacitors, did not know that yet!

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