I seem to be having a run of failed repairs at the moment and while it’s disappointing to write-up a repair that didn’t succeed, it’s important to learn from failure.
A colleague asked me to look at a Parrot camera drone recently as one of the drone’s motors wasn’t running correctly. The fault developed after a visit to a lake where it got a little wet. It turns out that this model isn’t water-proof, despite the £300.00 price tag!
After drying out, when powered back up, one of the four motors wouldn’t spin at full speed. These motors seem to operate in several phased windings and it would appear that one of the motor’s phases was missing.
Upon opening up the drone, I discovered that the PCB had indeed suffered water damage along its main processor. However, three of the motors were fine and camera was working OK.
The double-sided printed circuit board (PCB) presented me with a dilemma. This PCB was fitted with extra tiny components and multi-layered board technology, presumably to save weight and cost, so a repair using conventional soldering techniques was unlikely to get good results as the excessive heat would more than likely damage other components. Located near the wiring connector that connects to the motor that wasn’t working properly, were several tiny surface mount fuses, one of which appeared to have failed. Assuming I could locate the right component, attempting a repair on a PCB like this would more than likely yield a molten mess! At this stage I could have used a conductive glue to bond in a new component or temporarily bridge the fuse, but on the basis that I couldn’t guarantee a repair and the fact that there seemed to be water ingress to the whole PCB, I decided that a complete PCB replacement was probably needed. Sadly, I had to return the drone back to the owner with the bad news.