Well I don’t know anything about fixing constoles I got from ebey a Original Xbox and it said it was tested I get it in 7 days I set it up and It gave problems saying it can’t read the disc but even when I Get it to start the game it stops working 
I just wanted to play some old games but I guess not I want it fixed
If you bought it on eBay and the listing said it worked but it doesn’t work them just open a “not as described” case. Buyers easily win those. That all being said it’s likely that it needs a new laser.