I have a houseful of 1970's Marvin's. These have a balance spring only on the right track. One spring is stuck near the bottom of its travel so the sash wont engage it. Does anyone know how to release the spring? Can't find anything on the internet for windows this old.

 

Got a photo?

 

Sorry, no photo. I'm old and can't make my computer acknowledge my phone. In any case, I'm painting these and reinstalled the sash today and it magically engaged the spring. I'd tried this multiple times over a couple years, so have no clue how it works. OK for now.

 

Its a little hard to help when we don't know what window or what part you have.

here is a history of Marvin double hung and single hung parts... Maybe you can figure out for yourself what model you have if you look for single hungs from that era. It's 96 pages long so you can see how difficult it would be for us to guess what you have.

Most Marvin's that I recall just have a sisscors style of balance clip that is just supposed to engage when you drop the sash down on it, so I'm glad you got it to work.

 

That Marvin history is interesting, if nothing else. However, I can't identify what window I have. Key features are:

1. Removable outer panes, not sealed double panes like modern windows. (You can clean all of the glass)
2, Removable lower sash, but not tilt out.
3. Aluminum track hardware. Left track spring loaded horizontally. You compress it with left force to remove the
lower sash. Right is rigid with lift balance spring.
4 Wood sashes, not clad.

From Marvin's history I could not find a window that met the above criteria. Our house history is that the 2nd story with these Marvin's was added sometime in the 1970's. Astonishingly, these things still operate pretty well, but offer little in energy efficiency.