Teledyne 514 - NDIR analyzer - Manual (Page 43)

5–5
Maintenance & Troubleshooting 5.0
Teledyne Analytical Instruments
A Business Unit of Teledyne Electronic Technologies
2. Loosen bottom nut on coaxial connector so that connector can be
pulled free of the receptacle.
3. Remove mounting screw used to secure subassembly base to
detector compartment interior.
4. Release the subassembly box from its mounting flange and
carefully remove it from the compartment. The two additional
connectors are the slip-on type and can be slipped off of their
receptacles as the subassembly is removed.
5. After the subassembly box is removed, the box can be opened for
removal of the circuit card.
6. Make certain that the slipon connectors are properly installed and
that the nut is tightened on the coaxial connector. Reverse the
removal procedure to finish reinstallation.
5.6 Re-screening of Lens
Gain resistor R4 in the preamplifier establishes the voltage output to the
clamp circuit (see dwg. A-14619). The resistor is selected for the application.
If there is too much light for a particular application, R4 is reduced to
approximately 1 megohm. If there is still too much light, the light path can be
attenuated by installation of a screen in the lens holder, held in position by
the installed lens.
5.7 Troubleshooting
When troubleshooting the analyzer, it may be helpful to note that the
reference and measuring level signals are split at the peak level detector.
Thus, if one of the signals is faulty but not the other, it might be an indication
of a malfunction in the peak detector circuit card, ahead of the log amplifier.
If the meter indications are the same, but too high or too low, it may be an
indication that something is malfunctioning ahead of the peak detector
circuit.
Use waveforms and voltages in this section to isolate troubles to spe-
cific components or circuits.
In the event of an electronic malfunction, always check the power
supply voltages before starting a detailed troubleshooting procedure.
The voltages given in the waveform and voltage tabulations are not
necessarily exact under all operating conditions. Depending upon the
application and various potentiometric adjustments, they may vary. They are