2 Used Anycubic I3 mega printers in need of help.

I am new to 3d printing and looking to use this as a chance to learn more for the future. I have purchased 2 second hand Anycubic I3 Mega printer, Taking a chance on them being the pair was only $100 and came with extra extruders, filament, heating beds, steppers and a few other thing I can not recall at the moment. I am very handy when it comes to fixing things like this but before I starting making a mountain out of a mole hill wanna get some feed back.

The first printer when powered on will sound the power supply fan and one internal green LED, yet nothing else seems to function. I went through the wiring to find one loose/disconnected ground wire and reinstalled. Still no power to the screen or movement in the motors ( I would assume the motors would do a little function on startup). That is the first one.

The second printer does nothing upon powering up. The green internal LED is constantly on when plugged in and power off though, Im thinking bad power switch.

Even if I can get one running and have the other as parts or fix it in time is my goal and I only have 117 day until Halloween. LOL
Any help is appreciated and I will continue to do some research on my own.