Broken block & tackle balance

A home owner from Monkton, MD 21111 says:
I need to repair or replace one or two balances in wooden double hung sash windows. In replacing the cords I found several parts missing. These are 1/2" x 5/8" X 24" LONG METAL balances with 10" springs and metal foot clamps. They have no.162 stamped on the outside of the channels and no other identifying info on them or the windows. These windows are in otherwise great condition and were installed about 1965 or so.
A customer submitted photo of channel balance attachments.
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Paul from SWISCO responded:
Thank you for your patience in this matter. Can you please confirm that the length of the metal channel is 24"? The reason I ask is that a balance of this style should be 25-1/2" long. I just want to confirm with you before we do anything definitive.
A quick learner from Monkton, MD says:
Yes, all 8 of the balances I have are 24 1/2" total length. And are in good shape but for missing one of the double pulley assemblies which attach to the spring and a foot bracket (shown above)which anchors it to the base of the sash. I've recorded most of them, but the cord I have is a bit thinner than the original braided sash cord. Thanks for looking into this. - Mike
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Paul from SWISCO responded:
Thank you for your patience in this matter. After extensive research, we have determined that we are unable to help you in this matter. I sincerely apologize for the inconvenience. I would try contacting your window manufacturer to see if perhaps they can help you, or maybe your local hardware store.
A quick learner from Monkton, MD 21111 says:
I've already tried everything local and on the web I can find without success. I have no way of knowing the window manufacturer and was hoping you could provide replacement 1/2" balances that would work or some knowledge base for identifying the manufacturer or someone else that could possibly do so. Seems to me that with all the selection you carry, something else would work in this application. Thanks for your time. - Mike
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Mike from SWISCO responded:
We will try our best to find a solution for you.

Would you mind submitting a few pictures of your window and how the attachment works with the window? We would like to get a better understanding of how your original balances work.
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