How much diffusion oil for a 733 pump?

[cogswell]

Hello friends;

I have a truly venerable jeol 733 from 1986 that's still in service but extremely cantankerous and no service contract, so it's all up to us.  A variety of wondrous disasters over the last twenty years including the OL blowing out a plug and vomiting it's oil all over the inside of the microscope.   I've bought two other dead 733's over the years to swap parts with. 

Lately I have a lot of bad vacuum and short filament life and I was asked to change the diffusion oil (which is santovac, I changed it last about 2005).  I got some new santovac and I'm wondering if anyone knows how much "should" be in the reservoir.   I did this so long ago I have no recollection and can't find a reference in the manual.  JEOL sells a santovac charge of 100 mL so I figure it's that or less.

I don't think the dp oil, if it is a problem, is the only problem, but it's one I'm currently tasked with.   

I was thinking I could just check from how much oil comes out but the suspicion is that 733's oil level is depleted in the diffusion pump so the amount that comes out may not be enough.

Steven Cogswell
UNB Microscopy