The Black Christmas Marathon | December 24 | 24 Hours | Scream Factory TV

I'm trying to remember an old slasher movie of the 80's in which the killer is a woman! I remember only this scene (because it shook me up when I woke up and saw it, then covered my head with my pillow): a man pulls the chain-switch to put on the light in the dark cellar. The woman swings with a machete and hacks his hand clean off! The man screams and holds his handless stump. The woman finishes him off and the camera shows his hand which was still holding the chain, drops down in slow-motion.
WHICH movie was that???

Nothing but trailors???😮

let's go!