I have been working on a project, basically converting a tray-loading iMac G3 into a docking station for my 2017 MacBook Pro. I removed the motherboard and was able to find a VGA converter that connects to the DB-15 cable from the iMac's monitor. After monkeying with the power supply/ATX, I hooked it up to my roommate's PC, set the resolution at 1024x768 @ 75 hertz and voila! It works great. However, with my USB-C to VGA converter on my MacBook, it doesn't. The iMac's onboard monitor is not flexible and won't run unless at 75hz. I am able to switch to other resolutions in the system preferences, but all of the options are at 60hz. The system seems to recognize the monitor as an LCD panel, I'm not sure if this is an issue? I tried using SwitchResX, but it isn't able to do anything, despite having disabled Security Integrity Protection. I am not super savvy with MacOS script/patching or whatever the lingo is, so I am desperate for help. Or maybe is this a hardware issue with the MacBook? Anything helps!