MS 5975C - Sequence not starting - 'MS parameter 64.256 is outside the allowed limits: -0.0313 to 64.0313. Sequence error.'

Hello,

I am experiencing unusual problem. As in the subject, my sequence stops right after attempting to run and MS parameter 64.256 error is logged in the Current Logbook. I have never seen anything like this before.

I did some maintenance before that happened. I cleaned the ion source as always. When trying to tune it later on, tuning stopped few times showing an error of MS parameter 64.256 being out of range. I managed to finally tune it using a previous tune file as a template, but the tune report was not great. High EM voltage suggested me to replace it, and I did it as it was old anyway.

I managed to obtain a good tune this time but that was the end of my luck. Happy to run a calibration, I proceeded with starting a sequence and then it refused to run.

Can anyone suggest what to do? I have attached few recent tune reports for better understanding. 

Many thanks in advance.

Parents
  • Hi Gosia,

    A couple of issues that I see. The repeller is very high for all the reports that you have posted. If the PFTBA level is acceptable in the vial (if you can see any, its enough), then I would suggest changing the repeller insulators and repeller. The other concern that I see is the back ground, you have a lot of background with several hundred peaks showing. This could be a dirty or failing HED assembly. Background peaks should be much less, easily below 200 peaks.

    Regards

    James

Reply
  • Hi Gosia,

    A couple of issues that I see. The repeller is very high for all the reports that you have posted. If the PFTBA level is acceptable in the vial (if you can see any, its enough), then I would suggest changing the repeller insulators and repeller. The other concern that I see is the back ground, you have a lot of background with several hundred peaks showing. This could be a dirty or failing HED assembly. Background peaks should be much less, easily below 200 peaks.

    Regards

    James

Children
  • Hi James,

    Thank you for your comment.

    My repeller was always that high. I was thinking that it could be due to the specificity of my instrument. It is a GCMS combined with a TD system. It is used for an air analysis and there is always a little bit of water coming from the samples. I will change the insulators on the next source clean though.

    Not sure what a HED assembly is, but after reading other forums it looks like this may cause my issues...

Was this helpful?