DO AT YOUR OWN RISK!
This is how I fixed my roller blind.
4 motors of eBay costs about $20usd
part needed: FC-280SC
Dimensions are at the end of the video
video is very brief & straight to the point
SYMPTOMS:
When you press up or down, it goes about an inch and stops
removing motor and powering it directly with 12v and it will seem to be ok
The problem is one of the two small inner motors inside of the L10 motor has given up.