Focomat Ic lamphouse removal?

Hi,

Does anyone know how to remove the complete lamphouse of a Focomat Ic so that a replacement Wallner color head can be installed? I've opened up the top half and removed the condenser but I can't see any screw whatsoever to remove the lower half of the lamphousing.

The type of Focomat I have is this:
http://4.bp.blogspot.com/-LkAVzBt6Awk/UNsLJCYG0QI/AAAAAAAAA34/znJK___As_M/s1600/DSC_0933+copy.jpg

Thanks

Please do not dismantle this beauty.

I'm not dismantling it. I just want to try a different lightsource.