Didn't you say you're in Belgium? That must be an import transformer for 220V operation. Either way, it looks like the screw bolts the transformer together are missing and somebody ran a wire through where one of the holes. You need some long screws and nuts. The layout of the transformer and bridge rectifier is different than anything I've seen. Usually there's a large capacitor where the transformer is in that pic, and the transformer is farther down towards the power amp board. The board connections are soldered on instead of a card-edge connector, so that might indicate it's one of the later blueface 150's.