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Greetings list,

Two questions:

1) Does anyone know what the current range THROUGH the filament is supposed
to be? I am not referring to the emission (~ 1.0 mA). We are having a
complete loss of signal and right now it looks like the current through the
filament is not varying as a function of the potentiometer (physical
potentiometer on the face of the instrument). When I vary the potentiometer
I see no variation for most of the travel and the a sudden drop to zero
volts (across a resistor that escapes me at this moment).

2) For the Isodat software 2.x on windows xp, if I vary the HV [steps],
from 0 to 3000, what should I expect in terms of real high voltage
variation? For example, if I measure voltage between (yes using appropriate
high voltage probes and caution) ground and "col".

To call out two of you that may be listening (Peter and Christie), we
talked at the clumped conference about this loss of signal issue. The
source connections are all sound (I vented it and checked each connection
which were all very solid). I also measured no connection between any
feedthrough and another (apart from the 0.2 ohms for the filament). I also
observe expected magnet strength when I hold a metal object near the magnet
during hysteresis.

Thank you.

andy


-- 
Andrew Schauer
206.543.6327
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*http://isolab.ess.washington.edu/ <http://isolab.ess.washington.edu/>*