S/5 EEG Module, M-EEG and S/5 Headbox, N-EEG
Document No. 800 1011-1
15
4
TROUBLESHOOTING
4.1
Troubleshooting chart
Trouble
Cause
Treatment
No EEG waveforms on screen.
EEG waveforms not selected on screen.
Press Monitor Setup key and select EEG
waveforms on the screen.
No EEG waveforms on screen and ‘EEG
measurement off’ message shown in the
number field.
Electrodes not attached properly to skin or
electrode cables not connected to headbox.
Check electrodes and electrode cables.
All EEG Waveforms not drawn on screen
even if electrodes and cables are OK.
The number of channels chosen on montage
setup is smaller than the number of
channels connected to patient.
Check that the number of channels in menu
Others
-EEG - Montage
is same as the
number of channels connected to patient.
Number fields show ‘---‘ and message ‘High
EMG’ is displayed.
Patient has high muscle activity in the head
region or noise from some equipment is
coupling to electrode cables.
Relax the patient or remove the noise
source.
EEG signal looks noisy and artefact message
is displayed in the number fields.
Electrodes are poorly connected or electrical
interference is coupling to electrode cables.
Check the electrodes and electrode
impedances. Remove noise sources if
necessary.
Leads off message is shown on other
channels than channel 1 in referential
connection.
The montage chosen in monitor is not
referential.
Change the montage to referential from
monitor menu
Others
-EEG - Montage
.
Electrode impedance measurement is not
available on menus.
EEG measurement is off.
EEG measurement starts 15 seconds after
first electrode pair is connected.
Electrode impedance measurement is not
available on menus.
EP measurement is on.
Wait until EP measurement ends or stop EP
measurement.
Electrode impedances show ‘---‘ and check
ground electrode message is displayed on
number fields after impedance
measurement.
Ground electrode is poorly connected to
patient or ground electrode cable is not
connected to headbox.
Check the electrode and cable. If the
electrode has too high impedance (>50k)
the measurement fails even if the electrode
is properly attached. Cure for this is to use
better electrodes or prepare the skin better.
Electrode impedances show ‘---‘
The electrode impedances are too high and
out of measurement range.
Prepare the skin better or use better
electrodes.
Start EP measurement not available on EP
menu.
The EEG measurement is off.
Connect electrodes and wait 15 seconds
and the measurement starts.
EP measurement parameters cannot be
changed.
The EP measurement is on.
Stop EP measurement.
All or most of the EP epochs are rejected
(Rej. counter on EP screen increases more
rapidly than Ave. counter).
The signal has too much noise/artefacts in
EP measurement band. Especially coupled
50/60 Hz is not shown on EEG waveform
because of filtering, but may be present in
EP signal.
Check that electrode impedances are below
5k and the impedances of the same
channel are close to one another. If this
does not help then try to remove noise
sources.
EP wave is shown only on one channel even
if two channels EP measurement is selected.
Leads are off in the channel where the EP
wave is not shown.
Check the electrodes and electrode cables.
No clicks can be heard from earphones.
The earphones connector is not in place.
Check that the earphones plug is firmly
pushed into the headbox’s earphone
connector.
