Block and Tackle Balances, a No-Hassle guide to Balance Replacement...by a Guy in a Flannel
If those metal channel things in your windows are broken, they need to be replaced. In schools, commercial windows can have block and tackle balances in them when the original windows were installed. These can be replaced, and you don't need to be a magician to do so. Check this video, if you're a facilities director, send this to the maintenance crew and they can learn to do it themselves. So get to it, and before you know it they'll be poppin' takeout clips like Jay-Z poppin' bottles.
Commercial window repair is a specialization, and part of that is knowing how to replace window operators in schools and universities and residential applications.