62
BG 805 981 BE (0201) QMG422.oi
Problem
Possible cause / Test methods
Correction
No measurement signal with
EP 422 or CP 400
Try simulation
Replace QC 422 if not ok
Cabling not o.k.
Check, see p. 23 u. 24
Wrong detector selection
Set
detect-TYPE
correctly
No emission
Switch on
filam
Emission too low
Adjust: see test report
No SEM high voltage
Switch on
sem:
, see also error 34.
QME 125 fuse F1
→
[3]
SEM high voltage too low
Increase:
detect-SEM
channel dependent
sem hv-SEM-VOLTAGE
channel independent
See also Error 34 for HV 420
No high voltage with HV 421
See Error 34
Field axis voltage too low
See test report
v1..v6-F-AXIS (possibly V4)
QME125
→
[3]
Wrong ion source parameters
See test report, QMA400
→
[2],
QMA125
→
[4]
Resolution too high: try integral spectrum
with
mass-RESOL:OFF
.
If integral spectrum exists adjust resolution.
QMH 4x0
→
[1], QME 125
→
[3]
No measured value with EP 422
EP in wrong connector of QMH
Check
→
23
SCAN-N
with 10 ms/u,
range
10
-9
A
Disconnect EP 422 from QMA, touch input
with screwdriver
50 (60) Hz signal should appear
Check signal with an oscilloscope, if not o.k.
replace EP 422
No measured value with CP 400
Threshold too high
Decrease
amplif-CP-LEV
→
48
Electrometer signal negative
EP1 and EP2 cable mixed up
Check, see p. 23
POLARITY switch on QME 125 set to "–"
Set POLARITY to "+"
Electrometer offset strongly
mass dependent
Loose ground connection (EP input or below
QMA connector plate)
Tighten / correct
Open shielding below QMA connector plate
QMA 400
→
[2], QMA 125
→
[4]
Electrometer signal:
- not zero between peaks
- negative / small peaks missing
Offset not aligned
Perform offset correction
→
47
Offset in
range
10
-12
very high
Temperature of the EP 422 too high
Decrease
Bad insulation collector to flange
(good:
>>
1 G
Ω
)
Correct insulation fault
→
QMA 400
→
[2],
QMA 125
→
[4]
Moisture in electrometer or on analyzer
connector
Dry with warm air (no over 60 °C)
→
64
Electrometer signal sensitive to
vibrations
Knurled nut loose on EP input
Shield below connector plate of QMA not
correctly installed
Tighten
Correct shielding
QMA 400
→
[2], QMA 125
→
[4]
High noise signals with EP 422
Analyze signal (
amplif-MODE:FIX,
SCAN-N
,
high
SPEED
) with PC or
elm
signal with
oscilloscope
Remedy noise or choose slower
SPEED,
DWELL
and/or increase
amplif-FILTER
High counting rate with CP 400
also besides peaks
Corona or arcing in CP 400 or
in HV 420
in HV 421
in high voltage cables
in QMA or SEM
Open CP 400 and dry with war air (<50°C),
Remove dust.
Replace HV 421
Replace cable
QMA 400
→
[2], QMA 125
→
[4]
High counting rate with CP 400
also without high voltage
Poor ground connection, shielding open,
coupling of parasitic signals, e.g. with
isolated system set-up.
Correct
Establish shielding or decouple
Measurement signal:
-Limited to values <10 V
-Jumps to 10.24 V
With
SEM
and
FIX-range
10
-11
and 10
-12
A
EP 422 overdriven
Use Autorange or
RANGE
10
-10
and higher
SEM voltage
7.4 Measurement signal problems