INFICON SQM-242 Thin Film Deposition Controller Card Operating Manual - Manual (Page 57)

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SQM-242 Operating Manual
3. Control voltage output
does not function properly. a. DAC board damaged from
applying voltage to the
control voltage output. a. Ensure cable connection
to the DAC board does not
have a potential across the
contacts, contact INFICON
service department.
b. Reversed polarity of
control voltage relative to that
accepted by the source
power supply. b. Verify source output
polarity of the DAC and the
required input polarity of the
source power supply,
reconfigure the SQM-242 if
necessary.
c. Improper control cable
fabrication. c.Check for correct cable
wiring.
4. Frequency reading is
unstable or drifting. a. Temperature (of the
crystal) is changing. An
AT-cut crystal frequency may
drift as much as 10 Hz/°C. a. Control the temperature of
the chamber. Check watering
cooling for flow and
temperature. Check source
to crystal distance (12" is
ideal)./
b. Humidity (level on the
crystal) is changing. Moisture
being absorbed or exuded
from the crystal surface. b. Control the humidity of the
chamber.
c. "Unbalanced" or damaged
coaxial cable. c. Check cables for any sign
of damage. Replace cable if
found. Perform continuity test
on cables.
Table 7-1 General Troubleshooting
SYMPTOM CAUSE REMEDY