I just picked up a plethora of Omega D5500 equipment (3 heads, 4 controllers, lots of negative masks etc.) after watching the video of Allen Ross on this month's Lens Work (he raves about this enlarger). I found a photographer in Hamburg who does catalogs and he has switched to digital and has no more use for these enlargers. Lucky me! I have been trying everything out and it seems like most everything works. The filter mechanisms in all the heads sound a little rough though and I would like to try and clean one thoroughly and restore it to smooth function as best I can. Can anyone provide any information on how to do this? I read somewhere that there are small rubber bits that move the dichroic filters into place via friction and that these can be adjusted and cleaned, it would be great if someone could provide a brief guide before I start to disassemble one of the heads. BTW: I have the Controller III version with the closed loop automatic dichroic lamphouses.