Internal parts of 360's are coded. the motherboard will only work "online" with the disk tray it comes with. They can be swapped out but if you put the console online the code will send a red flag and the console should be banned offline for life. one of those small type, agreement things.. tampering, hacking ext.
Externals should be easy enough on e bay with the holiday season approaching, or at least a gamestop if you feel the need to take a small % of value in store credit

or Mech's awesome advise!
My advise if someone is buying broken units above scrap...sell sell sell
my current xbox is smashed and the hard drive is held in with electrical tape, gotta take the disk tray apart once in a while to tighten those screws so it will eject the disk's lol. Been trough a few rrod machines, tear em up and scrap em out is about all they are good for IMO.
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