Models 947, 948 and 960 Leak Detectors Operations and Service Manual
4-15
4.2.5.2 Disassembly of the Spectrometer Tube and Preamplifier
To disassemble the spectrometer tube:
1. Remove the four screws on the spectrometer tube (Figure 4-3), noting the placement of
the grounding strap
➀
.
The grounding strap must go back on the same screw during reassembly.
CAUTION
The preamplifier is a static sensitive device. Wear a grounding
device while the preamplifier is being handled.
2. Loosen the four 5-64 Allen set screws on the edges of the magnet assembly that hold the
fixed and adjustable pole pieces in place.
3. Remove the pole pieces
and the black plastic tuning knobs
.
4. Separate the magnet assembly
➁
from the spectrometer tube body
➂
.
5. Remove the four Phillips head screws that hold the flange cap
➃
onto the spectrometer
tube body.
6. Firmly but gently separate the flange cap from the ion source
➄
.
7. Remove both the O-ring on the ion source, and the ion source.
8. Remove the ground slit plate
➅
from the ion source cavity with a long, thin
screw-holding screwdriver.
9. Remove the four slotted screws on each side of the spectrometer tube body and slip out
both deflection pole pieces
➆
. The deflection pole pieces are interchangeable.
10. Remove the O-ring.
11. Remove the heater cartridge
➇
by pulling it free of its cavity.
12. Remove the five Phillips head screws that hold the preamplifier cover
➈
on.
13. Remove the preamplifier
➉
, connector bracket, and collector housing assembly in the
following sequence:
❑
Remove the Phillips head screw at the base of the connector bracket.
❑
Remove the four socket head cap screws, sized 8-32, that mount the collector
housing to the spectrometer tube body, using a 9-64 short Allen wrench inserted
between the printed wiring board and the screw head.
❑
Remove the metal seal on the collector housing assembly.
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