no tune peaks showing on 5975

Hello,

I have inherited a 5975 MSD and when I go to autotune, there are no peaks present and the tune fails. I get alternating errors "Gain and Offset = 0 and peaks are too narrow" or "Tune action stopped: The valid Range for Ent Lens Offset is 0.00 to 64.00, Step 0.25"

I've cleaned the source, installed a new filament, and replaced the PTFBA but I still have the error. The last tune that this instrument had that I could tell was in 2017. I've tried to restore previous tunes but none of them work so I have replaced it with the default atune.u file. I'm not sure how this instrument has been stored in the last 5 years. A new column has been installed and the He flow is set to 1 mL/min with ~1-2 mm sticking into the MS. I don't detect any leaks from the column ends. Additionally, this is the first single quad instrument that I have dealt with, and the Hi Vac reading is around 2.7e-3 which is a lot lower than what I am used to seeing with the 7000C (around e-7). Is this a normal vacuum for a single quad or could this be the issue for not seeing any peaks?

The air and water check doesn't seem to be working properly because it isn't finding any of the tuning peaks to compare with? H20% = 333.54, N2 = 0%, O2 = 320%, CO2% = 116%.  Unfortunately, I have a relatively low budget so I must prioritize purchasing on what is most likely the issue.  The Repeller is slightly scratched on the bottom surface, and I plan on replacing it once I can order a new one. Additionally, there are a few slight scratches on the draw out plate, which I also plan to replace.  It unfortunately looks like someone may have used a Dremel to clean these parts.

Any advice is welcome. Please let me know if any other information would be helpful. Thank you.

Figure 1. Tune failed with Gain and Offset error

Figure 2. Ent Lens Offset error

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  • It looks like an incorrectly sized ferrule (0.32) was used at the GC/MSD interface. Once I reinstalled the column with the correct ferrule (0.25), the vacuum held at the correct pressure. This was my first experience in which an air leak did not cause a vacuum shutdown error. Thanks again for your help!

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