jkloepping wrote:
I've been having a problem with my 5973 where the repeller voltage keeps reaching max (30 volts) no matter what I do. "atune" checkout fine, but I'm not happy with the ion ratios. "stune" works, but produces a dirty looking 502 peak. The machine produces pretty good results, but I'd like to improve things.
I've cleaned the source more than once, changed filaments, ramped all the source voltages to confirm everything is at least changing, with no results.
Air and water check is pretty good, everything below .5%.
I realized that I used an inert repeller in my non-inert source. Does this matter? There is a shallow divot in the inert repeller that I assume simply identifies the inert part, does the orientation of this matter?
This raises another question: can you use the entrance lens from the 5975 in the 5973? The part numbers work, but the design is somewhat different, in that the "neck" of the entrance lens has a reduced diameter collar.
The only thing I think is different is if you get parts from a CI source, otherwise they should be interchangeable. I have even mixed and matched Inert and non-Inter in a pinch. The "dot" on the repeller if it is on the back side of the disk does indicate inert I believe, on the front side it might just be a nick from something hitting it.
If the repeller is maxing out at 30v, what is your emission current setting?
You can lower the peak of the repeller by lowering the emission current most times. If it is 35uA then try lowering it. I run some instruments as low as 19uA with no problem. You drop sensitivity a little over all, but it becomes more biased to higher masses as you lower the current, which might help with the 502 shape.