Been noting an in-common chararectic recently with some but not all SFc 10-4 lampholders used commonly on Mac 2K, VL3K and a lot of other moving light fixtures. Hard to see but the lamp on the left looks normal (shiny) but it has some scratches on the lamp base which are dull - not fresh from removal. Not deep or extensive, just some scratches that are matt in finish as if a bit of corrosion. Finding that it's common that when I see these scratches, following the next lamp the lampholder for the fixture will go bad. At work it's really hard to change lampholders/sockets according to manufacturer guidelines short of the fixture itself tracking such a thing which it doesn't. Too many people changing lamps and too many fixtures to track such a thing at this point. Often those changing lamps also don't inspect lamp or lampholder for a bad one also. VL3K fixtures are especially hard on lampholders - run a bit hotter. So anyway, these scratches are not always seen on a lamp killed off by a bad lampholder, could be other things causing this overheating, but it does indicate one potential cause. Note the cement on all also is darkened which might indicate overheating or just an older lamp also not an indicator unless chipping off or really dark. Still, I'm finding in a good amount of lamps/fixtures tracked that when I see some not too deep scratches but deeper than what would be from insertion/removal on what otherwise appears to be a good lamp, following the next lamp, the lampholder will be shot if not fail due to a bad lampholder before its time. Should not see scratches on a lamp base - scratches indicate ares on the socket which don't allow full surface area of contact with the lamp thus higher resistance for what places do touch and thus an overheating. Something to note & from left to right note the sort of melting in marks on the lamp base due to this overheating and or bad lampholder. Than also the discoloration of the lamp base and cement.