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

[coredump]

Yes, 100mL.

733, 8600 and earlier version of 8800 use 100 mL of LION S diffusion pump oil. Late 8800 confuses me. The label on DP indicates LION S 100 mL but JEOL person said it uses different expensive DP oil.

Other possible problems of the vacuum system are flanges and valves (solenoid valves, pneumatic valves and butterfly valves).
I guess your 733 has latest version of vacuum system, so pipes and pneumatic valves are connected unknown (I couldn't find standard) or JEOL specific flange. Older 733 uses gage port like flange.
I replaced all O-rings and solenoid valves of our 733s, then they have good vacuum conditions.

Yet another issue of the 733 vacuum system is 5V power supply. The linear regulator 7805 supplies 5V. Damaged 7805 produces lower voltage than 5V and causes unstable vacuum sequence.

KATO Takenori

[cogswell]

Hello friends;

Since this was mentioned in the latest probe software email I realized I had not followed up on this and that's bad of me. So here's some followup.

I have a second DP from another 733 (Anelva CDP-600) and that pump has a label directly on it saying "105 cc."  My suspicion after I found that was that my pump in my actually running 733 had a similar label but it's long since been burned off. 

We did replace the oil in the pump, and when we drained it we did not get very much santovac out, which had been in there since probably 2005.  Maybe 40 mL came out?  It was very uhh.... thick and rich black santovac as well. 

Having said that, replacing the oil didn't fix out vacuum issue but we did, I believe, find the vacuum issue, and that was one of the thin windows one of the gas-flow spectrometers.  Although that gas-flow line passed the 'bubble' test (put alcohol in the bubbler and watch the bubbles come out), when we pinch off the incoming gas flow the alcohol got slooooowly sucked back up the hose.  We had to narrow it down to which spectrometer it was, and after replacing the window our vacuum is much better.  Not fantastic, but we pump down in a more reasonable time and filaments don't pop every three days.  This probe is from 1986 and stillllllll works.