Converting mid 2010 27” iMac to a monitor

@ronaldbaker the panel should be a LM270WQ1(SD)(E3) so for that there are multiple inexpensive universal controller systems out. Something like this should work reasonably well. Same principle as shown here Utilisation d'un contrôleur universel pour écran LCD applies to that panel as well. You got most certainly enough room in the original enclosure to make it all fit.

One of the only challenges you will encounter with any of these kits is that the brightness will be lower than what you might be used too. It's the nature of these kits that their IC's do not receive the high power that a desktop would provide.