Did I fubar my motherboard by hacking my MagSafe?

My MagSafe power supply went out and I tried to save a buck by cutting off the magnetic end that plugs into the computer. Then I took a universal power supply stripped the wires and tied them to the stripped end. I may have also reversed the polarity by mistake. I heard a little tiny pop and pulled it off quickly. I then went later and purchased a new 45 watt MagSafe power supply but it wont power on. Are there any parts that I can replace or troubleshooting that I can do or did I just fubar the motherboard? The universal power supply has a variable voltage that is supposed to automatically adjust. I did pull off the cover and test after the dc in board to where it plugs into the logic board with the new MagSafe supply and it had good voltage at that point.