Entrance lens and ion focus not ramping

[JFo]

Hey guys,

We are having problems with our 5973 MS which is connected to a 6890 GC. Initially we were having trouble with an increase in EMvolts and an air leak. We found the airleak, re-cleaned the source and did a big clean/maintenance on the machine. Now we are having trouble with the auto-tune. The tune runsfine until it gets to the ion focus lens/repeller/entrance lens section and doesn't give any parameters and therefore increases the EM-volts at the end of the tune trying to find the PTFA peaks. (We abort the tune when we see this so as to not ruin our filaments or EM horn)

When we go into the manual tune we put parameters into the manual tune which we got from an auto-tune which previously looked good. When we try ramping the entrance lens/repeller/ionfocus lens we get straight lines:



However, the scan and profile are fine:


All of the cords connecting the source are correctly connected.

Any help would be greatly appreciated

[Bigbear]

Are the connections tight? If they come off with a slight tug with forceps they are too loose.

Have you tried one of the other tunes? S tune, bfb or dfttp tune? The tune files can become corrupt if you over write them a lot.

[Steve Reimer]

If you cleaned the source did you reverse the entrance lens and ion focus wires? Its easy to do and embarrassing to admit. (Even the service guy didn't notice right away)
The clue will be that the ion focus won't ramp properly.

[tlahren]

If you cleaned the source did you reverse the entrance lens and ion focus wires? Its easy to do and embarrassing to admit. (Even the service guy didn't notice right away)
The clue will be that the ion focus won't ramp properly.

Steve is right. This happens quite often. I would check this first as it's an easy check. I have also seen sources with some Alumina powder left behind on them causing problems. Even the tiniest bit can cause tune problems. Double check the cleaning of the optics after you verify the electrical connections are correct.

[Rick]

Your atune file is corrupted....i have this problem occasionnaly
First, close your GC, MSD and computer and restart all
Go to MSDchemsation menu, then go to View section
Select Tune and Vacuum control
Go to File and select Restore previous tune
Select a tune on this list then, if the peak shape is good, save this tune with a new name like atune02
Apply this tune file to your method
Return on instrument control and tune

[JFo]

Hey Guys,

Yes you were right it was a corrupt tune file... all is good now