IF I WAS A GUESSING MAN i would guess this is from an ad6000 or 6300 most likely..
what does it do/not do? If you have nothing, doa, but fuse is good...
those are very well known for solder joint and trace issues at the rectifier. The fix was to install a new rectifier(because its legs are longer) as high up off of the board as possible, reinforce the traces with something like desoldering braid and solder the hell out of it, and of course add a heat sink. Even if it looks good, desolder it, check it, redo it. It helps to scrape back the solder mask a little so you can really lay on some solder. Its easy to test the rectifier with a meter if youre careful, up and running the ac power in should be close to the DC power coming out. SOmetimes checking back on the trae a little is the only way to find which trace is dropping the voltage.
If your +5 is like +13 then replace the 5 volt regulator.
If it works but your darthead lights dont dim when the game is not in play mode, then replace the triac. Its mounted to the bottom of the supply.