Answer by
LeheckaG (1826)
The-counter-weights are BEHIND the-wood-facing on either-side of an-old-wooden-frame-double-hung-window.
If the-old-ropes broke or wore-out,
the-counter-weights may have fallen in the-wall down to the-floor-boards or even-farther below.
Use a putty-knife to score through the-paint around the-face-boards,
use several-flat-edges to pry the-face-boards off to-access the-counter-weights.
You can "fish" for the-old-counter-weights with a-wire-coat-hanger (avoid-live-wires).