Help: Tune problem: Cannot achieve constant peak width GC-MS

[Ajit]

I am using Agilent 7890A-5975C Gc- MS system. I am getting a problem while autotune. It shows cannot achieve constant peak widths. I have not done any maintenance recently and it was working fine until last week. I was trying to run a standard but got no peaks. Then, I checked for leaks but there are no leaks. Everything else seems fine. In the manual tune the peak is at 219 for PFTBA. I tried to see if tune file is corrupt. I copied tune file from mssetup folder as suggested in some topics and run autotune again but still the problem persists. What can be the possible source of this sudden problem? Please help.

[tkubowicz]

Hello

I'd try 2 things:

1.Try to run different tune - quick tune or standard spectra tune to see if problem is only with autotune mode

2.Reconfigure MSD - go to "MSD config" (it is on desktop) and remove MSD from configuration (of course note IP address). Then configure it again. Try tu run tune after re-configuration.

Good luck

Regards

Tomasz Kubowicz

[Ajit]

I did try both these options. But still I am getting same problem. I tried many previous tune files but none of these converge to a successful tune. I also configured a few times but no improvement. I had no problems in system before that abnormal shutdown of computer. I am running chemstation on windows xp professional and it had a abnormal shutdown once a week before. Since then I am getting this problem. So, I guess it should be related to software. before that my emv was never more than 1800 so i don't suspect end of lifetime of electron multiplier horn.

[tkubowicz]

Hi

If you checked options I recommended and it is still has problem with tuning perhaps you have electronic issue with MSD. It is possible especially after power shutdown.
I think next step is MSD board diagnostic - it is service procedure so perhaps it is job for Agilent or service company who supports your lab.

Regards

Tomasz Kubowicz

[James_Ball]

If you are in manual tune and doing a profile scan, what do the peak widths look like? Are they normal shape, or possibly tailing or fronting?

Also do the peak widths remain in the 0.5-0.8 range with very consistent numbers for at least 15 minutes?(consistent numbers meaning the widths do not vary more than about 0.05 over that time)

If the peaks are wide, or change widths over time and you have not opened the analyzer recently or ran any unusually dirty samples, then odds are it is a problem with the side board. The 5971/72 had problems with the quads deteriorating over time but the gold quads in the 5975/75 solved that problem, so unless you physically damage or change the alignment or bump the quad wires and cause arcing or grounding then most problems with peak widths are problems on the side board. You can power down and pull the covers off the side board and look for any burn marks or swollen capacitors or resistors, if you find that kind of damage the diagnosis is easy. Easier still was when one of ours actually was smoking while it was running, easiest trouble shooting I ever had. If you find that is the problem the good news is the side board is easy to replace, the bad news is they aren't cheap, but not nearly as expensive as the analyzer itself.

[01310040231]

You may have a corrupt tune file. Load an old tune and check the system.