I assumed it was a worn-out balance, but I am having trouble identifying even the type of the device, and how to remove or replace it.
The gray metal covers in the channel have no identifying marks, nor do the windows. We have similar windows with a Marvin marking elsewhere in the house, but it seems to be an old model.
All I can see of the mechanism is a small device attached to a cord under tension which seems to be fixed in the channel below the sash on the left side. A cord under tension runs down into the device. On the right side, there seems to be a similar device hidden behind the bottom of the sash, and rides up on it.
I assume that the left one is somehow jammed, and is supposed to be up with the sash providing support.
Is this mechanism something you can identify? Am I right that the little mechanism is supposed to travel with the sash? How can I remove and replace the whole thing? Do you offer a replacment?