INFICON RQCM - Quartz Crystal Microbalance Research System - Manual (Page 93)

RQCM – RESEARCH QUARTZ CRYSTAL MICROBALANCE
TROUBLESHOOTING GUIDE 10-1
10 TROUBLESHOOTING GUIDE
This section is intended primarily as an aid in understanding the RQCM operation and to help
insolate possible problems with the RQCM. If it is determined that the problem lies inside the
unit, please contact the factory for further assistance.
Symptom Possible Cause Remedy
Wrong line voltage is selected at
the rear of RQCM
Set line voltage on RQCM rear
panel to match with line voltage
being used.
Line fuse blows when the power
switch is switched to “on”.
Incorrect fuse rating. Replace line fuse with correct
fuse size.
Blown line fuse. Replace fuse
Power switch is not on. Switch front panel power switch
to “on”.
No power being applied to unit. Check and correct power source
and/or power cord.
None of the front panel LED
indicators illuminated.
Wrong line voltage is selected at
the rear of RQCM.
Set line voltage on RQCM rear
panel to match with line voltage
being used.
Unable to adjust fine and coarse
adjustments to compensate for
capacitance
The total capacitance of the cable,
crystal, and crystal holder is out
of the range of 40 to 200 pfd.
Adjust cable length to
reduce/increase its capacitance.
Crystal fundamental frequency
exceeds the frequency range of
the crystal channel.
Verify crystal frequency against
crystal channel frequency range.
(To verify the crystal channel
frequency ranges, press Reset
button and observe the output. A
3.8 MHz indicates the channel is
set for 3.8 to 6 MHz. A 5.1 MHz
indicates a 5.1 to 10 MHz.)
Replace crystal.
Unit does not lock onto a
frequency when a crystal is
installed.
Crystal resistance exceeds the
range of 5 and 5,000 Ohms.
Replace crystal.
Unit looses lock when crystal is
exposed to liquid.
Total capacitance of the crystal,
holder and cable changes when
going from air to liquid.
Adjust capacitance compensation
with crystal in the liquid. Refer
to Section 3.4.
Unstable frequency reading when
the crystal or the holder or the
cable is being touched.
Same as above. The crystal
measurement is reacting to the
change in total capacitance when
the setup is being touched.
Avoid contact with the hookup
during an experiment. This is
especially important if the crystal
is a low Q crystal.
Temperature (of the crystal) is
changing. An AT-cut crystal
frequency may drift as much as
10 Hz/°C.
Control temperature of the test
environment.
Frequency reading is unstable or
drifting.
Humidity (level on the crystal) is
changing. Moisture being
absorbed or exuded from the
crystal surface.
Control humidity of the test
environment.