Problems with Osborne 1A brightness consistency and screen distortion towards top and bottom edges

[robotguy600000]

I've been working on an osborne 1a recently and noticed some weird vertical brightness inconsistencies as well as stretching and compressing of the image towards the top and bottom of the screen. the stretching and compressing isn't very visible in the photo but comparing it to the other video outs shows you what i mean. I tried adjusting the picture using the pots on the crt board but that didn't do much. the crt board does have some electrolytic caps but they aren't leaking or bulging at all. i plugged the video out of the screenpak module into my pc using an adapter and that gets rid of distortion problems, but there are still issues with the brightness. i am fortunate to own an original osborne one external monitor, and when i connect it to the 1a and power it on, both forms of distortion are completely gone altogether. this problem is thouroughly confusing and and hunches or solutions to it would be greatly appreciated since i can't find anyone with the same problem. Although i have been doing some work installing a floppy emulator, this problem existed before i started so i don't think that me poking around inside and the problems are related. the pictures of the physical screens have the brightness turned way up to demonstrate the problem, but the picture from my capture card is unmodified and looks like that no matter how i adjust the brightness and contrast. one last final piece of info is that the physical screen dims whenever i plug in an external display to the screenpak video out. I'll try to answer any questions asap.