Finally working on the small system again. I did get the copper conflat seal and installed that and have not touched the system since.

Couple weeks ago I decided to take another whack at the system. First issue I have found is the turbo is not happy after a couple hours of running. Not sure what going on, it starts vibrating, I think the bearing I replaced is not up to snuff. I did try putting the turbo on a dedicated chiller to see if that stops it thinking that maybe the bearing was getting hot and the race gets a little looser but it didnt fix the problem. So I am trying to get a quote from alpine bearing for a new one.

Then the thermocouple gauge head died. Got an old Varian 843 from a friend to replace it. Much nicer than the old one. Next I had more water leaks. One of the brass parts of one feedthrough was cracked though and another fitting was split. I machined a new part and replaced the other. 

Thats when I found out I had a leak someplace. Couldnt get below about 8x10^-5 torr. I tried spraying everything with alcohol to find the leak that way, nothing. Tried argon, nothing. Got out the RGA. Its was dead, would not talk to the laptop. Replaced that comms board. Now it talks but shows a huge spike from about 5 amu to 20amu. As in it maxes out the scale. I took the RF section off a spare unit and stuck it on there and that seemed to fix it, I was able to retune it and was good to go.

The next day I went to Target and picked up a bottle of balloon helium. Rigged up a flowmeter and a hose to make a helium sprayer and started going around each joint. Eventually I found the ASA flange between the isolation valve and the chamber was leaking like a sieve. I took the eight 3/4' bolts out that held it together and used a toe jack to lift the baseplate off. It was pretty dirty. I pulled the o-ring out and ordered some replacement but I measured wrong. Whoops. So I cleaned the old one, put some Krytox on it and put it all back together. Pumped it down and after about an hour or so it hit 9.5x10^-6. Much better!

Next thing was to replace the big ferrofluidic feedthrough for the shutter. It was so big that it was partially blocking access to the adjacent baseplate ports which I needed for other things. I remove the feedthrough and installed a bellows type rotary feedthrough. I adapted the existing shaft arm to the new feedthrough and installed a pneumatic rotary actuator to open and close the shutter with s small solenoid valve. This way I will be able to control it with the deposition controller. 

While I had the table off I found some pretty major air leaks so I went about fixing those. While I was doing that I discovered the people that had pieced this system together had connected the differential pumping connection of the planetary rotary feedthrough to high vacuum instead of the roughing line. A differentially pumped feedthrough has a shaft sealed with two o-rings. the section between the two o-rings is pumped down with the roughing pump, this creates a simple feedthrough that handles high vacuum. 

I hooked it up to the roughing line like it should be and found that the feedthrough was leaking, Bad. I couldn't even pull 2 torr in the roughing line with the roots blower pumping. I could actually hear the thing leaking. Luckily I had a spare offset drive that was brand new and just replaced the existing one. When I got the old one off it was a mess. I could see where stuff was falling from the bearings, tore it apart and the bearing just fell apart. I tore it all the way apart and pulled out the two o-rings which were toast. Cleaned the housing out and installed new o-rings with krytox. Polished the shaft where it ran against the o-rings and knocked off burrs from people messing with it in the past. I found a new bearing in my stash and took off one shield and cleaned out any remaining lubricants and put in some krytox and put it all back together. Much, much smoother. I also took the final drive bearings out and cleaned them out and krytoxed them as well. They probably could be replaced but they are a narrow race full compliment bearing that looks expensive.

RGA installed on the system. Lucky for me I had a compression fitting on a elbow I was able to use to connect the RGA.

RGA going through its autotune process.

The source of the leak, cleaned this up and its good to go, Also installed some shorter bolts to make life easier. 

The rebuilt offset drive rotary feedthrough. Whats left of the bearing and o-rings next to it. 

The little pneumatic rotary actuator for the shutter. Solenoid valve below with it's own regulator.