Varian 4000 GC, Hardware Operation Manual

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8. Go to “Checking the Vacuum Status” on page 48.
9. If in external or hybrid mode, turn on the damping gas and getter heater
using the buttons in the lower left of the startup/shutdown dialog.
10. Go to “Baking Out the Mass Spectrometer” on page 49.
11. Go to “Checking Ion Trap Operation” on page 49.
Checking the Vacuum Status
Select the Diagnostics tab in System Control.
Vacuum System Field
The vacuum readings (at the lower left of the screen) tell a lot about the state of
the MS after pump down (and during operation). Typical operating ranges for the
4000 MS in internal mode are:
Speed 100%
Current
200 – 300 mA
Power 9 – 13 Watts
Ion Gauge Pressure
< 20
μ
Torr
Foreline Line < 50 mTorr
If the Pump Spin Speed does not steadily increase, there may be a leak in the
system. Large leaks will be indicated by a turbo speed less than 100%. Small
leaks will show up by an increase in the pump current once at 100% or in the ion
gauge pressure (See
Diagnostics Mode
section in the 4000 GC/MS Operation
Manual, 03-914999-00.) Small leaks are diagnosed by changes in the ion gauge
reading and can be pinpointed using the leak check section in the internal or
external service method. For more detail on troubleshooting leaks, go to the
“Troubleshooting” section (page 107) on checking for air leaks.
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