I had 10+ go out on mine in a wide array of locations (not just the supposed "problem locations," and not just single-LED PCBs either) before they finally sent me an entire replacement set of the redesigned 7.5v boards (and 7.5v power supply), which seems to have fixed the problem for now. The worst was one of the boards under the castle playfield, which required that the whole thing be disassembled every time I had to replace it.
They should be sending complete sets of boards to ALL owners who have the original flawed style, if you ask me. If it was worth hiring a new engineer to redesign them completely, that says something was seriously wrong with the original boards. The old machines need to be fully retrofitted, not just patched up one board at a time.