Some mass spectrometer work from today:
I actually haven't dug into doing the electronics retrofit I'd planned just yet. Rather, I'm actually taking the time to try and get it back to something resembling new performance.
The person who sold/gave me a bunch of parts also gave me his thoughts on how to properly clean a mass spec source-something that I THOUGHT I knew how to do, but according to him I was focusing too much on the wrong parts and not on the things that really matter. His explanations all made sense when I thought in terms of how various parts interact with the ions, and what dirt/crud/other build-up does to them. His explanation of what happens when those various parts DO get dirty also mirrors what I've been seeing on this.
So, consequently, I spent some time today really cleaning up the source with his recommendations. Hopefully I will get a good tune out of this and can then can proceed with bringing a c.1990 5971 up to the standards of a c. 1993 5972

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Shown here is the mass spec with the top board removed and the source removed and disassembled. Also, the two rods in the foreground are the official Hewlett-Packard issued rods to clean the inside of the ion lenses. Despite the fact that the current Agilent 5977, for which many of the parts in the standard source are directly interchangeable with the parts in this 30 year old 5971(the draw-out plate, draw out cylinder, ion focus lens, ion entrance lens, and lens insulator could be directly replaced with new parts specced for a 5977, or these could be fitted to a 5977), HP/Agilent does not included these cleaning rods and hasn't for a long time. After having it explained to me how important the inside surfaces of these parts are, I'm not sure why they've been left out.
In any case, I cleaned them with "green paper"(Agilent 5061-5896) and followed by a slurry of aluminum oxide(Agilent 8660-0971). I did a lot of scrubbing and polishing, and feel good about how clean they are.
Normally, my next step would be to pump it down, but I realized something. To do it properly, you need a part called a blank ferrule to seal the end of the transfer line where the column would normally be attached. I have a package of them in my office and meant to grab them, but walked off and forgot it. I searched through my tool kits and have every imaginable type of standard ferrule-graphite, vespal, graphitized vespal, and a number of different internal diameters, but don't have the elusive no hole. I can improvise by taking a piece of capillary column, installing it, and jamming a septum on it as a cap, but I don't even have a junk capillary column here. So, I can't pump it down until I get one.
Also, I'll be interested to see how well I can get it pumped down. Normally, the source and quadrupoles are kept at elevated temperatures. The HP/Agilent 5973 and newer have discrete heaters on these parts that are controlled by the mass spec. Somewhere around 200ºC is normal for the source, and 150º or so for the quads. The 5971 and 5972 don't have separate heaters, but instead intend for you to get the transfer line really, really hot(280ºC or hotter, where it's normally 200-250º on other instruments) and have it serve as a heater for everything else. That normally gets the temperature at the source/quad interface(where the only thermocouple is located) to 160-170º. Unfortunately, the transfer line is heated by the gas chromatograph, and I didn't bring that home with me(it's big and I don't have 20A plugs at home to plug it in). So, I'll just have to hope it gets everything pulled off.
That's my rambling for the evening!