Window won't catch the channel balance

A home owner from california says:

I replaced the channel balance with #2830's I just received from you. I have tried three windows, one worked fine. the other two do not catch the new channel balance. I noticed the small black piece on the window itself is missing on one side which would seem to catch the channel balance on the way down. Is it possible to order that small black plastic piece and might it just be worn on the other making it not catch the channel balance?

which part might that be?

Image 7874 is the black piece located on the window (not the channel balance window frame, but the window itself). there should be one on each side of the window top sides

I think I see that it might be the top sash guide that I need.? I will go try to figure out what size Or which one I need. thank you.

Thumbnail of the uploaded file named IMG_7881.JPG
Thumbnail of the uploaded file named IMG_7879.JPG
Thumbnail of the uploaded file named IMG_7878.JPG
Thumbnail of the uploaded file named IMG_7874.JPG
Thumbnail of the uploaded file named IMG_7878.JPG
Profile picture of Bob
Bob from SWISCO responded:

Thanks for posting, and thanks for your patience during our busy time of the year. You are correct: you need new top sash guides to get the window sash to 'catch' your channel balances. It's a bit difficult to tell what top sash guide you need from a picture of a damaged version. If you want to confirm with us what kind you need, seeing an undamaged version out of the window, with 'mugshot pictures' of the front and side, would be most helpful. Many thanks. 

How to Repair a Jammed Window
How to Repair a Jammed Window
VIDEO
WATCH >
How to Replace a Top Sash Guide [1080p]
How to Replace a Top Sash Guide [1080p]
VIDEO
WATCH >
Reply to Thread
Use this form to ask a follow-up question or to share your experience regarding this subject.
(your email address will be kept private and is only used to inform you when a response has been made)
Current wait time is 3-4 business days
We promise that one of our experts will personally get back to you as soon as they are able. Thank you very much for your patience and understanding. If your inquiry is time-sensitive, please feel free to reach us at (888) 991-1929 or at help@swisco.com.