Series 4060 | Maintenance | |
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measure resistance between that wire and the remaining undisturbed terminal. Resistance of the thermistor varies with its surrounding temperature. A reading of between 10KOhms and 16Kohms at around 25°C may be measured. (Under very cold conditions, the resistance could be as high as 50KOhms; under hot conditions, just a few thousand ohms.) If the thermistor measures anywhere in this range, it is most likely OK. Otherwise, if the circuit is short or open, check the wires leading to the thermistor,
2.Check the heating element by measuring its resistance. Disconnect one of the heater wires from either terminal 2 or terminal 4 on the temperature control board P/N B30927, heater wires are black, and check the resistance between that wire and the remaining undisturbed terminal. If a reading of approximately 100 Ohms, then the heating element is most likely OK. If an open circuit is found, check the heater wires and a possible connector between the heater and temperature control board. If no problems are found, and the heater circuit is open, then replace the heater element.
Note: If any of the components located inside the isothermal chamber has failed, the instrument must be removed for service. If no problems are found with either the thermistor or the heater circuits, then replace the temperature control board.
5.3 Ignition and/or Flame Guard Circuit Checks
If the flame guard circuit will not hold the
1.Disconnect the
2.Check the flame guard sensing thermistor by measuring the resistance between pins
Teledyne Analytical Instruments | 69 |