Refurbed and sold a 1952 Twenty Grand. The bumpers have a graphite ring / spike system for scoring. Rather than the typical spike in spoon system of modern games. The buyer is having a small problem with the spike / ring getting out of alignment on a couple bumpers. Is this typical and just essentially a result of a bad design, which was abandoned for pretty much this reason. Is there something that can be done to keep these in alignment better? Or is it better just to replace them all with the modern style? There are 8 of these on the game. Two pop, and six dead bumpers.