I've done a few mister...
Specky's top tip.....
Use a bench vice and clamp the runner
use a spare battery and bench test it.... if it sounds like broken glass...you've crossed wires on the drum...
remove the long wire from the slider
Open up the drum lid, route the cable back on the drum (To do this, you'll need to keep tension on the wire to stop it bird caging and crossing over again, keep the tension on till back in the slider)
Put the lid back on the drum
place the cable back in the slider
bench test the little fella again
Hope that helps
This may help too....TTFN
If you have a problem, if no one else can help, and if you can find them, maybe you can hire... The N/A-Team.