ILX Lightwave LDC-3700C Series, User Manual, Page: 171 / 176

C A L I B R A T I O N A N D T R O U B L E S H O O T I N G
Troubleshooting
04_09 LDC-3700C Series
155
C H A P T E R
5
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Troubleshooting
This section is a guide to troubleshooting the LDC-3700C Series Controllers.
Some of the more common symptoms are listed here, and the appropriate
troubleshooting actions are given. We recommend that the user start at the
beginning of this guide. Read the symptom descriptions, and follow the steps for
the corrective actions which apply. If you encounter problems which are beyond
the scope of this guide, contact your ILX Lightwave customer service
representative.
Table 5.3 Symptoms and Actions
Symptom Corrective Actions
General
LDC-3700C Series unit will not power up Check AC Power line voltage and power cord
connection.
Power on, but display is frozen, switches
do not operate This may occur if the instrument loses power (AC
line) briefly. Turn the power switch off and on again
to restart.
Laser Contoller
Power on, but no current output Check Interlock pins on LASER input connector on
instrument rear panel. These pins must be shorted
either directly or through a switch.
If OPEN CIRCUIT indicator is lit check the load
connections and then try again.
Check the OUTPUT ON switch, the corresponding
LED should be lit.
Output current at limit, cannot be lowered If POWER mode is used, check the monitor diode
(feedback) connections. Try reversing the polarity
of the monitor photodiode. Check also the
photodiode bias adjustment on the rear panel.
If in I or I
HBW
mode, check the current set point and
I LIMIT setting. Setting the output below the limit
may require several turns of the adjust knob if the
set point is much greater than the desired limit
setting.
Output goes off intermittently Check the interlock circuit. An intermittent interlock
will turn the output off.
Check that the AC power cord connection is secure.
Power-line drop-outs may reset the unit and when
power is restored, the output will be off.
Unable to adjust output Check the (ADJUST) LASER indicator, the indicator
must be lit for any LASER adjustments to be made.
Check the I LIMIT parameter for the output range in
use, see that it is set above 0 mA.
Power Mode operation has high output
current, but little or no power is measured Check back panel PD BIAS. If set too low, may act
as an open feedback loop. If in doubt, set the PD
BIAS to mid range (2.5 V).