Thanks for contacting us, George. I believe you have an old style Air Control operator which isn't available anymore. That said, take a look at our
39-017 which is similar in design. The only issue is you will need to drill the bottom hole on the operator to match the hole in the window.
What I've done in some cases was to drill the holes in the operator to be a little larger so I could fudge the installation screws. It's not perfect, but it works. It's really up to you how you want to approach it.
The link arm is also a little different in terms of length, but there is a some travel in the operator gears that should make up the difference. I don't think it will matter that much.
I also recommend looking over the other parts related to the
39-017. I made a list for you to review.
Lastly, if you aren't happy with the
39-017, then you could consider our
39-280. This has the same mounting holes as yours, but the link arm is too different and no amount of travel will make up for it. You would need you to drill out the link arm on the
39-280 and your old operator, them swap them. You would also need to locate the correct rivet at a local hardware store that will get the old link arm to install on the new operator.
At the end of the day, I personally think the
39-017 would be easier to deal with.