INFICON STM-2XM 2-Channel Rate/Thickness Monitor - Manual (Page 123)

6 - 3
PN
07
4-
61
4-
P1
A
STM-2XM Operating Manual
Crystal fail Failed or defective crystal, or no
crystal in sensor. Install a new crystal.
Two crystals were installed or
crystal is upside down. Remove extra crystal.
Reverse crystal orientation.
Inspect crystal for scratches; if
scratched, replace with new
crystal.
Build-up of material at crystal
holder aperture is touching the
crystal. Clean or replace the crystal
holder. Refer to the sensor
operating manual.
Crystal frequency is not within
the Min and Max frequency
settings. Install a new crystal.
Use a 6 MHz crystal.
Excessive cable length between
oscillator and crystal. Use no longer than a 78.1 cm
(30.75 in.) in-vacuum cable.
Use only the 15.2 cm (6 in.)
cable between oscillator and
feedthrough.
Sensor not connected, or bad
electrical connection in sensor
head or feedthrough, or bad
cables. Check sensor connections.
Refer to the sensor operating
manual.
Use an ohmmeter to check
electrical continuity / isolation of
sensor head, feedthrough,
in-vacuum cable, SMA/BNC
adapter cable, and BNC cables.
Refer to the sensor operating
manual.
Substitute a 5.5 MHz test crystal
or a known good sensor for the
suspect sensor.
Crystal fail Bad coax cable between
feedthrough and oscillator, or
bad coax cable between
oscillator and STM-2XM. Use an ohmmeter to check
electrical continuity / isolation.
Substitute a known good coax
cable.
STM-2XM or oscillator is
malfunctioning. Substitute a known good
STM-2XM (or other QCM).
Substitute a known good
oscillator.
Table 6-1 General troubleshooting (continued)
SYMPTOM CAUSE REMEDY