Varian 990 dCLD II, Operation Manual

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Model 990 dCLD II Component Leak Detector
5-20
5.5.1 Reassembly
1. Replace the ground slit plate (see Figure 5-21 on page 5-17).
2. Replace the ion source (see Figure 5-21 on page 5-17).
CAUTION
Refer to Figure 5-21 on page 5-17.
The ground slit plate has a hole in it that must be aligned with
the hole on the bottom of the spectrometer tube body ion
source cavity
➂
. The ion source must be aligned so that its
alignment pin
➃
falls in the center of this hole.
A short could result at power up if the alignment pin touches
the sides of the alignment hole.
3. Carefully reassemble the spectrometer tube assembly in the reverse order of these
instructions.
5.6 Manual Tuning
To manually tune the 990 dCLD II, the system must be attached to a vacuum system and be
running with the setup parameters as described in Section 3.3 “Initial System Parameter
Setup” on page 3-7. Note that the actual value of the calibrated leak is not important for the
first part of this exercise, only that a maximum value is achieved.
NOTE
Attempting to change calibration requirements when
PARALLEL ENABLE is active will either result in the change
being rejected and a response of
cant being received through
the serial port, or if the optional front control panel is installed,
the menus not being accessible.
5.6.1 Manual Tuning via the Serial Port
1. Operate the valves in the vacuum (external leak) system to rough pump, then expose
(turn on) the calibrated leak to the foreline of the spectrometer assembly high vacuum
pump.
2. Wait approximately 20 seconds for the leak to stabilize.
3. Set the Ion Voltage to its nominal value by entering the command, 250 PUT-ION<CR>,
and the Variable Focus to its nominal value by entering the command,
190 PUT-FOCUS<CR>.
4. Change the value of the REPELLER parameter in 10 V steps starting at 320 V using the
PUT-REPELLER<CR> command.
5. Check the leak rate at each step by using the ?LEAK<CR> command.