There's a hex screw on the side that might need to be removed?
Also, you might need to press the pcb mounted power connector inwards. Gotta be careful with that though, as you can break it off with too much pressure. Had to do this with some EHX pedals, and what worked best for me is to put a piece of wood (or whatever) that's only slightly larger than the gap, place it inside and turn it until it snaps straight... 1 or 2 mm will do the trick.
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