Granville-Phillips 830 VQM Quick Start Manual

Turn OFF and disconnect power to the VQM
beginning this filament replacement procedure.
1. The components of the MS Gauge are fragile. Be especially
careful when disassembling and reassembling the gauge.
2. Do NOT scratch the ConFlat knife edge on the gauge.
3. The components of the filament replacement kit are UHV
compatible − perform the replacement procedure in a proper
cleanroom environment.
Components of the Filament Replacement Kit
Figure 1 Replacement Kit
NOTE: The filament replacement kit includes a custom pair of
tweezers that are notched to grasp the retaining ring.
Retaining
Ring
Plasma
Screen
Figure 3 MS Gauge Components - Viewed from the Port End of the Gauge
Alignment Pin
See Figure 5
Filament Latch
See Figure 5
3. Remove the retaining ring. Use the tweezers provided in the kit to squeeze
the tabs together and carefully lift the retaining ring from the gauge. Be
careful not to scratch the ConFlat knife edge when removing the retaining
ring.
4. Remove the plasma screen.
Figure 4 Retaining Ring and Plasma Screen Removed
WARNING
®
Controller before
CAUTION
Tweezers to grasp the
retaining ring
Copper
Gasket
Filament
Assembly
1
Retaining Ring
Plasma Screen
NOTE: The filament
assembly is under the
plasma screen.
3
Filament Replacement Instructions
Be sure to read through and understand the scope of this procedure
before beginning.
NOTE:
Use clean, vacuum component compatible gloves while replacing the
filament.
1. Turn OFF power to the VQM System and vent the vacuum chamber to
atmosphere. Disconnect the cable from the MS Gauge and remove the 6
bolts that attach the MS Gauge to the vacuum chamber. See Figure 2.
Figure 2 Remove the MS Gauge from the Vacuum Chamber
2. Look closely at the port of the MS Gauge and make note of the position of
the components as shown in Figure 3. Orient the gauge as shown in
Figure 3.
5. Use tweezers or small needle nose pliers to rotate the latch
counterclockwise and unlatch the filament assembly so it can be removed
from the gauge. Do not use excessive force when unlocking or locking the
filament latch.
Figure 5 Filament Assembly Latch
Filament Assembly
Alignment Pin
Filament Latch
Locked (Closed)
6. Use tweezers or small needle nose pliers to carefully lift the filament
assembly from the gauge. Note the position of the alignment pin and the
center pin (latch pin). Also note the position of the filament (which is near
the alignment pin hole in the ceramic disk) and the filament port which is
in the gauge assembly. Figure 6.
Figure 6 Position of the Filament and Alignment Pins
Alignment Pin
Latch Pin
CAUTION
2
Latch Pin
Filament
Assembly
Latch
Filament Latch
Unlocked (Open)
Filament
NOTE:
The Filament
Assembly is
shown upside
down in this
Ceramic Disk
illustration.
4