I ran over the cable on my Dyson DCO7, there was a loud noise when the cable got stuck in the brushes and a brief burning smell. I switched it off and tried it later, it seemed OK but the brushes aren't turning. I checked the belt an it's intact. The brushes turn OK manually.
Most likely the inner belt broke. You can either choose to replace the clutch assembly (which contains both the belts) or just replace the belt. The belt that you need is the longer and thinner one. It is actually quite easy to replace. All you need is the belt and a torx 10 screw driver. To get your clutch out for repair, search for "Dyson Clutch" on utube. There's a video that shows how to do it. Good luck mate!
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