Replacing a operator for a Thermalguard casement window

A quick learner from Toms River, NJ says:
It looks like I need to purchase the 39-091 operator for a Thermalguard casement window. My problem is how to remove the plastic bracket that covers the whole length of the bottom of the window To get to the operator arm. It is screwed in under the covering. Your video shows how to remover the wooden covering. I can't take it off to get to the screws. As you know, Thermalguard is no longer in business. Please help.
User submitted photos of a window operator.
Profile picture of Dave Sr.
Dave Sr. from SWISCO responded:
Thanks for posting. A few years back I did replace this kind of operator on a Thermalguard window. If I recall correctly, I think the sill cover snaps off to expose the mounting screws, but it has been some time since I did it. I do remember that it wasn't too much of a project, comparatively. Looking at your photos, I would also suggest replacing the hinge with the 36-013-10 along with the 39-505 track since you are going to replace the operator.
A quick learner from Toms River says:
Dave. Thank you for your reply. I ordered the parts. My question now is how to snap off the sill? I'm afraid that if I brake the sill, I won't be able to replace it as Thermalguard is no longer in business. Can you explain it for me? Tom.
Profile picture of Dave Sr.
Dave Sr. from SWISCO responded:
I'll try my best! You will need to remove the sill trim that covers the operator screws, that's the only way. Watch the video below for reference on what needs to be done. The only issue is, the sill trim in the video is wood, while yours is not.
It looks like there is a seam on the bottom of your sill cover. That means it might be one that snaps in place. Take a small screw driver or chisel and try to pry it up at one end to see if you have any luck, just like how we show in our video. You just have to be more careful that you don't crack or damage the plastic on the frame. If you are not comfortable doing this then I recommend hiring a handy person to come out and do it for you.
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