Teledyne 514 - NDIR analyzer - Manual (Page 61)

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Maintenance & Troubleshooting 5.0
Teledyne Analytical Instruments
A Business Unit of Teledyne Electronic Technologies
Proportional Heater PCBs
See dwg. B-15016. There are three proportional heat PCBs, all of
which are located in the power module.
1. There are no adjustments on this card other than the installation
of R2 per desired temperature regulation (see section 5.×:
Component Selection). The type and value of thermistor used is
necessary for proper selection of R2.
2. There are two ways of testing the controlling action of the PCBs.
The first is a preliminary test on the board. The second tests the
performance of the board in the 514 analyzer.
a. Test the heater PCB in the “heater card test jig” in TAI’s
quality control area. A potentiometer on the test jig will
simulate the thermistor resistance. As this pot is varied,
the lamp (simulating the analyzer heater) will turn on and
off.
b. Place the PCBs in their normal positions in the analyzer
power module. Connect a 100V neon lamp between the
case of Q1 and the positive side of C1, or across the
heaters. When the heater has reached temperature
equilibrium the lamp will blink on and off at a rapid rate
(fraction of a second) indicating proper proportional
control. A slow blink rate (several seconds) indicates ON/
OFF heat control, but improper proportional control.
Control Unit
Power Supply, +15 Volts.
To check the control unit power supply, plug in control unit +15 volt
power supply and check for +15 volts.
I-to-E Converter
See dwg. A-14620. This card has no calibration adjustments, so all that
can be checked is proper operation at the output of A2 (circuit board pin 15),
which is 0-1 volt out for an input of 10-20 mA at circuit board pin 14.