Teledyne 4060 manual Temperature Control Electronic Check, Collector Cable

Maintenance Series 4060

Whenever the flame guard and anode power supply printed circuit board have been replaced the analyzer must be recalibrated.

If the instrument performs as outlined in this section, the problem is not related to the measuring circuit electronics.

5.1.4 Collector Cable

Before reconnecting the collector cable, check the continuity of the center wire of the cable with an ohmmeter by measuring between the center pins at each plug on the lowest resistance scale of the meter. Flex the cable while making this measurement to be sure that there is not an intermittent open circuit. If there is, replace the cable. Do not attempt to repair the cable, as special tooling is required to disassemble and reassemble the cable plugs.

5.2 Temperature Control Electronic Check

If the heating circuit fails, the output of the analyzer will tend to drift with changes in ambient temperature. Such a failure will be more evident in the low range. If the temperature environment surrounding the analyzer is closely regulated, failure in this circuit might go unnoticed after the initial failure. If the environment follows day and night temperature changes, the analyzer will show a diurnal, bi-directional drift when operated on zero gas. The magnitude of the drift will be a function of the temperature differential experienced by the analyzer. To check the circuit, employ the following procedure:

Consult the 4060 schematic and assembly drawings, as well as the temperature control PC board schematic and assembly drawings at the rear of the manual for circuit details and component placement.

An indicator light behind the analyzer door cycles on and off with the heating element; the light is on when the heater is on, and vice versa. Failure of the light to come on at all when the cell compartment is cold indicates a problem in the temperature sensing or control circuitry or the wiring that interconnects the thermistor to the circuit. If the light stays on constantly, but the compartment does not heat up, then a problem with the heating element or connecting wiring is indicated.

1.Check the sensing thermistor by measuring the resistance between its connecting wires. Disconnect one of the thermistor wires from terminal strip on the temperature controller board, P/N B30927, the wires out of the thermistor are yellow, and

68 Teledyne Analytical Instruments