Purchased a cheap LED monitor with no power leads, how do I find the power leads?
I see at least two cheap linear regulator looking parts on the left.   It's a good bet that they share two nets, GND, and VCC input.  You should be able to figure out which one is GND, maybe you can trace it to the negative side of a capacitor, a gnd pin on the main IC, or maybe a tab on one of those connectors.   Then the other one is probably VCC input, and I bet you can trace it to one of those connectors.

You should check the regulators and see if there's any markings on them, then google for data sheets.   It's hard to see what they are with the picture.