Entry Lenses value 0

[SylvainL]

Good afternoon,

The sensitivity on one of our GC-MS is ~10x lower than the others. We are analyzing bde/bfrs using NCI. I decided to run an auto.tune and noticed that the entlens value is 0... I've tried changing the value through manual tune but it keeps going back to 0. I checked the wire connection for entlens inside the ms and it seems fine. I was wondering if anything else would give you 0 for entlens, other than no power to it?

Thanks

Sylvain

I hate wasting time knowing that it's probably something stupid

[SylvainL]

finally tune report looks normal... ended up changing tip seal, repeller insulator and filament (all 3 had scene better days). Now my tune report looks great.

[Schmitty]

Glad you got it fixed. What instrument do you have?

[SylvainL]

I'm running a 6890 (by agilent) with a 5973 in NCI mode.

I'm still not convinced that eveything's good though. The prob with this instrument is that there's too many user's

[SylvainL]

here's a general question pertaining to entlens value? what would make entlens' value vary from 4 to 30 in a short lapse of time? The source is clean.

Thanks

[Schmitty]

I cannot say what would cause it, other than a dirty source.

I will note that currently about half of the MSs I work with have the ENTLENS value as 0, while the others vary widely (5-22). We had an issue with Argon contamination over the last week, and since then half of the ENTLENS values dropped to zero.

[SylvainL]

wow have you noticed any changes due to the fluctuation in entlens value?

Thanks for the feedback, it helps

[Schmitty]

I haven't noticed a fluctuation in anything, especially sensitivity. On another, perhaps related, note; I had started using stune instead of atune for the instruments that are now exhibiting the ENTLENS=0 behavior.

[SylvainL]

I assume this prob was related to my other post... once i cleaned the source my entry lense value went back up to 28ish.

Thank you all

Cheers