The owner of the DC24 I replaced the main motor (as per the stickied how to) and brushroll motor for, and had the machine working brilliantly* again for messaged me earlier...
Brushroll stopped last night. Reset switch does nothing
He dropped it round earlier, and I had a look. Mmmm, it was indeed dead.
Off with the casing then, fire up the multimeter and...0. Was 330 coming out of it last time I did this.
Handily, I have a DC24 that I bought very cheaply (thread coming soon on that), in bits drying in the airing cupboard. I grabbed the working pcb from that, fitted it and... fixed!
I messaged the owner, told him what the issue is and have given him 2 choices, either keep the second hand PCB for no charge (and I'll get myself a new one), or I'll order him a new pcb and charge him what it costs.
Still waiting for a response, but whilst tidying everything away something caught my eye on the old PCB
So, if your brushroll motor has gone, you can either take the risk like I did and only change that, or play it safe and replace it AND the PCB for piece of mind!