10.2 Contacts on QMA 250 and QME 250
2
3
1
12
13
8
7
9
10
4
6
5
11
8
7
9
10
11
1
12
13
2
3
4
5
6
Fig. 34:
Contacts on QMA 250 and QME 250
1 PP (partial pressure)
8
GND
2 EM HV
9
RF+
3 Filament 1
10
Filament Common
4 Filament 2
11
Reserved
5 Anode
12
Focus
6 RF-
13
TP (total pressure)
7 GND
10.3 Checking the QMA 250 analyzer
NOTICE
Damage to components caused by cleaning
Do not clean either the filament or ion source, as this can damage or destroy the parts.
► Replace the parts if they are defective or contaminated.
The ion source of the PrismaPro has 2 filaments. In case of a defective filament, the PrismaPro can still
be used with the second intact filament. The previous use of the PrismaPro may, however, have influ-
enced the performance of the second filament.
Prerequisites
● PrismaPro deactivated
● Analyzer QMA 250 and electronic unit QME 250 disconnected
Required aids
● Ohmmeter (< 0.2 to 30 MΩ)
Procedure
1. Measure the resistance of each filament.
– The measurement can also be performed in a vacuum.
2. Measure the resistance of each pin with regard to the mass.
3. Measure the resistance of each pin with regard to each other.
4. Replace the filament or ion source if the measured resistance is not within the acceptable range.
Measurement
Pins
Measured resistance
Result
Filament 1
3 and 10
0.2 to 0.8 Ω
Filament intact
> 0.8 Ω
Filament defective
Filament 2
4 and 10
0.2 to 0.8 Ω
Filament intact
> 0.8 Ω
Filament defective
(see chapter “Contacts on QMA 250 and QME 250”, page 67)
Malfunctions
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