Andersen windows sash spring balance replcement.

A handy person from New Jersey, Fair Lawn says:
Hi there,
I have a problem everyone is talking about - broken strings.
So far I have removed the plastic cover from the top of the window to open up these spring balances.
Please see attached file. See no marks on them.
How could you help me in this situation to find a proper replacement?
It is a double hung window with two panes of he same size - outer size of the pane 35.5W x 271/8 H.
Windows could be 30 years old if no replacement since the house was build.
Please help.

Thanks,
Ed
Andersen balance
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Tom from SWISCO responded:
Hey there, Ed! Seeing a clearer picture of the stamps on your balance would let us be 100 percent sure. Going by the glass size is an unreliable method. If you cannot see the stamps, some customers have had success taking a piece of paper, placing it over the balance, and rubbing a pencil over the numbers. Please get back to us when you have the stamp.
A quick learner from Fair Lawn, NJ says:

Hi Tom,
finally on a very sunny day I took another look at spring balance box and saw some trace of a letter. Took a piece of sandpaper and the rest was reviled, please take a look at attached pix.
Also, unobstructed glass size is 32 3/8 x 23 7/8, please see how it compares against the mark on the box.

Thanks,
Ed
andersen balance
A quick learner from Fair Lawn, NJ says:
Hey Tom,
please take a look at even better pix.
I took a piece of sandpaper and scratched dirt from the surface,
as the result more information revealed.

Thanks,
Ed
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Tom from SWISCO responded:
Ah-ha. We nearly made a mistake, because the glass height formula was WRONG in this case... good thing you showed a closer view of the balance box, so we can make a positive ID based on the stamp. This is actually a 24-939 Andersen balance.
A quick learner from Fair Lawn, NJ says:
Hey Ben,
how do you figure out 24-939 Andersen balance?
Based on E95 9#27 5 84 or 11600-17?

just curious,
Ed
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Tom from SWISCO responded:
That's a great question, Ed. The answer is that you find the # in the code and pull out the numbers to either side of it. Your 9#27 mark corresponds to an Andersen 927 balance, which we replace with a SWISCO 24-939. The way this works is that 24-939 replaces a wide variety of Andersen balances, from 927 to 939, which are marked 9#27 to 9#39.

If you search the # code in our site's search bar, the correct Andersen balance should appear. Read the item description and make sure your balance number is listed as a possible substitute.
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