I need help!!! k40 laser

[j0nes92]

so I bought a second hand k40 laser off eBay as I thought it be quicker to get here as he only claimed to use it once the laser stopped working after having it 2 days but everything eles worked and after watching hours of YouTube videos I figured out I was best to change the power so I got a whole new unit. i tried to change it but like a idiot I put the power lead connect in the wrong port so when I turned it on it went bang tripped my electrics blow the the fuse in the plug.. and I tried putting the old one in and had have no power at at all now where as be for the laser was able to move I need some help is it fix able ? I was thinking a new motherboard or will it be more than just that or am I better off getting a whole new one