Roller shade repair question

I’m talking about the vinyl ones that are meant to roll up when you tug on them. Is there any way to fix them when they lose their tension? I guess there’s some kind of . . . mechanism (?) in the tube. Can it be tightened / brought back to its former springy self? Even though they’re pretty cheap I’d rather repair the ones I have. Thanks in advance to anyone with the sproingy technology.

yes, if the shade is half way down, remove from the bracket and wind the shade up some on the roll and place back in the bracket. it will have more tension. letting some out from halfway will lesson tension.

I’ll try it; thanks!