I am needing to replace the PCB in my flash, but I can't figure out how to get the two lower halves of the flash apart. I've removed all the exterior screws but there appears to be a locking tab on the inside that I can't undo. Its on the left side of the flash, opposite of the battery door. The part is CY2-1464. Does anyone have any experience or knowledge on how to open up a 580EX?

