About a week and half ago I picked up a new in box dell e773c. The owner claimed the box was only opened for the fb marketplace photos and that he had never used it before. The monitor was still in the original plastic and when I opened up the hidden service menu it did have 10 hours logged on it. Maybe 5-10 minutes after I turned it on and made sure my DP2VGAHD20 converter cable was working properly I started to notice some horizontal lines appear on the screen. They aren't evenly spaced and cover the entire horizontal width of the display and can also appear from top to bottom or intermittently and get worse the longer the display is on. I bought a second adpater cable just to rule out the chance it was the adapter. Have cleaned the pins on the vga with 91% rubbing alcohol in case they were oxidized but the pins look completely fine. Also its not a grounding or magnetic interference issue. I have not opened it up as I don't have any experince working on crts. If anyone has any feedback, it would be greatly appreciated. I'm curious if anyone else has experienced anything similar to this. Also wanted to mention I've been using the monitor mainly at 1024x768 at 60hz, if I use it at the same resolution but 75hz or 85hz it cuts down the amount of time I can use the display before they appear. If I use it at 60hz in the morning and its been off all night I can sometimes get 30+ minutes playing games before the horizontal lines appear. Also for what its worth changing display resolutions or changing hz causes the issue happen faster

Dell e773c jumping horizontal lines