How to get frames working correctly

[thereaverofdarkness]

I cropped an assembly machine image from 4x8 frames down to 4x7 frames. As far as I can tell, I've made all the necessary changes to adapt the entity code, but it keeps making the machine fade from view while it is running.

I changed this:
width = 142,
height = 113,
frame_count = 32,
line_length = 8,

to this:
width = 142,
height = 113,
frame_count = 28,
line_length = 7,

And the image was cropped in GIMP from 1136x452 to 994x452.

Am I missing something?