MKS Instruments UK Ltd
HPQ3 Hardware Manual – SP101019.101 October 2012
If you suspect a blown filament, carry out the following test before removing the analyser from the
vacuum system.
Connect meter lead one to analyser feedthrough pin 8, which is the common connection to both
the filaments.
Connect the second meter lead to pin 4 (Filament 1). You should read short-circuit.
Next connect the second meter lead to pin 10 (Filament 2), again your meter should indicate short-
circuit.
If either or both filaments are blown, the meter will indicate an open-circuit and the filaments will
need to be replaced.
If the meter reading suggests that the filament is good but the control unit shows a filament fail, the
most likely cause would be a break down in electrical continuity or contamination of the ion source.
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