I need a power transformer for roland sde -3000

If your transformer is fried then you will have to replace it of course, but if it has only opened the thermal fuse that is tucked into the primary windings then you can replace that and not have to replace the entire transformer. Be sure to use the same temperature and type thermal fuse as the original. You will find the thermal fuse tucked in where the ac power in wires go into the transformer and you may have to clear some plastic out of the way in order to get to it. Be very very carfull that you do not nick or cut or break any of the magnet wire that makes up the windings of the transformer. Good luck.