Aristo Cold Light

I have a D2 with a variable condenser light source and a 4.5 inch condenser. I bought an Aristo Cold Light Head today. It looks new in the original box. It s ays it is a D2, W45. It is two parts, a top section with the light and an end c ap with a cream plastic part. It looks like a hat. I have removed the light ho use and can not figure out how to install the cold light. There are no brackets on it. It looks as though it sets somewhere in side the original light house. All so what takes the place of the condenser housing to hold the negative in pl ace? I don't believe I have the wrong cold light. It is clearly marked D2. An y one with directions on how to install?

As I recall, you take off the light housing from the top. Remove the moveable condenser and the large condenser lenses that are in the aluminium housing at the bottom of the head. Place the diffusor disc in the aluminium housing and then the cold light head, bring the wires up through the top. Everything on the head is used except the condensers and the bulb housing. Should make sense when you look at it.

Tim's answer is correct. I bought a new Arista for a D-2 and built an encloser for the D-6 Chassis I bought. One thought however you might want to buy the latest Tube, a V-54, and install it. Cost +/- $75.it gives a better range of contrasts than the old tubes.