6 - 4
PN 074-550-P1D
SQC-310 Operating Manual
Frequency reading in
Sensor Information screen
is unstable or drifting (not
a normal frequency
decrease associated with
material being deposited
on the crystal).
Humidity level on the crystal
is changing. Moisture being
absorbed or exuded from the
crystal surface.
Avoid condensation by
turning off cooling water to
sensor before opening the
vacuum chamber to air, and
then flow heated water above
the dew point of the room
through the sensor when the
chamber is open.
Crystal or crystal holder
crystal seating surface
scratched or dirty.
Replace crystal.
Clean the crystal seating
surface inside the crystal
holder or replace crystal
holder. Refer to sensor
operating manual for
cleaning instructions.
Bad in-vacuum cable or bad
oscillator cables.
Use an ohmmeter to check
electrical continuity and
isolation of cables.
SQC-310 or oscillator is
malfunctioning.
Test the SQC-310 and
oscillator using the oscillator
test mode (see section 6.6 on
page 6-17).
Substitute a known good
SQC-310 (or other QCM).
Substitute a known good
oscillator.
Substitute a PN 760-601-G2
Sensor Emulator or a known
good sensor for the sensor.
Frequency reading in
Sensor Information screen
is an incorrect value.
Excessive cable length
between oscillator and
crystal is causing a
self-oscillation at a frequency
different than the crystal
frequency.
In-vacuum cable length
should not exceed 78.1 cm
(30.75 in.).
Use the 15.2 cm (6 in.) cable
between oscillator and
feedthrough.
Table 6-1 Symptom/Cause/Remedy Chart (continued)
SYMPTOM CAUSE REMEDY
To Next Page
Loading...
