128 Maintenance and Service 083730300A DCN8101
5.7.14 SUBSYSTEM CHECKOUT
The preceding subsections discussed a variety of methods for identifying possible sources
of failures or performance problems within the analyzer. In most cases this included a
list of possible causes. If the problem is not resolved at this point, the next step is to
check the subsystems. This subSection describes how to determine whether an individual
component or subsystem is the cause of the problem being investigated.
5.7.14.1 AC MAINS CONFIGURATION
The analyzer is correctly configured for the AC mains voltage in use if:
• The Sample Pump is running.
• The GFC Wheel motor is spinning. LEDs D1 & D2 (located on the sync/demod PCA)
should be flashing.
• If incorrect power is suspected, check that the correct voltage and frequency is present at
the line input on the rear panel.
• If the unit is set for 230 VAC and is plugged into 115VAC,
or 100VAC the sample pump will not start, and the
heaters will not come up to temperature.
• If the unit is set for 115 or 100 VAC and is plugged into a
230 VAC circuit, the circuit breaker built into the ON/OFF
Switch on the Front Panel will trip to the OFF position
immediately after power is switched on.
5.7.14.2 DC POWER SUPPLY
If you have determined that the analyzer’s AC mains power is working, but the unit is
still not operating properly, there may be a problem with one of the instrument’s
switching power supplies. The supplies can have two faults, namely no DC output, and
noisy output.
To assist tracing DC Power Supply problems, the wiring used to connect the various
printed circuit assemblies and DC Powered components and the associated test points on
the relay board follow a standard color-coding scheme as defined in the following table.
Table 5-9. DC Power Test Point and Wiring Color Codes
Dgnd 1 Black
+5V 2 Red
Agnd 3 Green
-15V 5 Yellow
+12R 6 Purple
+12V 7 Orange
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