Hi Manuel,
I have fixed a couple of these but I can tell you that AFAIK detailed service manuals do not exist. The division that mad them was closed down before anyone thought of archiving the CLIPS. Maybe a former HP/Agilent employee may have them but thus far none have turned up. If one ever shows up I would certainly want one. I have the C and D version of this generator.
Just ask away and I hope I can help you.
Sam