Carrier 69NT40-541-500 Operation And Service Manual
Also see for 69NT40-541-300: Operation and service
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Contents
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T-363 7–38Checking the Controller:a. Turn the unit OFF.b. Disconnect the six pin connector to the stepper drive from the controller.c. With a voltmeter set to read 50 volts DC, attach the positive lead to outlet pin A of the six pin connector, andthe negative lead to pin B or TP-9 of the controller.d. Turn ON the unit for 40 seconds, and watch the voltmeter. There should be approximately 24 to 32 VDCshown on pin A.e. There should be zero volts on pin B.f. After a short delay, the reading should rise to approximately 24 to 32 VDC on pin E.g. Pins C and D will have zero to 5 volts transistor logic (TTL) signals present, however, this can only bechecked with the connector assembled as this is an open collector type circuit.Checking the outputs on A, B and E will verify that the controller is supplying power to the drive module. To be thor-ough, and if it is desired, the signals on pins C and D can be checked as follows:h. Install a jumper assembly (Carrier part number 07-00408-00) to connect the drive module and controllerconnectors as shown in Figure 7.30.i. Connect the positive lead of the voltmeter to test connector socket C and negative lead to socket B, and runas before by resetting unit.j. Repeat for sockets D and B.Figure 7.30 Jumper AssemblyThere should be approximately five volts DC on sockets “C” and “D” (S1 and S2) when measured as above. If notthe connections or controller is faulty. If any of these pins are not consistent, the connections or the controller issuspect. Check and replace as required.7.23.3 Servicing the eAutoFresh Drive SystemTo replace the Drive Motor Assembly:a. Remove the bolts that secure the eAutoFresh Panel (3, Figure 7.31) to the front of the unit. Reach in, cut tiewrap, (2) and disconnect the motor connector (1). Bring panel to work area.b. Remove four screws (8) fastening the grille (7).c. Remove six screws (9) fastening the rails (5 and 11), the slide plate (10) and the gasket plate (6). Set com-ponents aside for reassembly.d. Remove the four screws (12) fastening the motor cup (4) to the panel. Cut sealer on outside and inside ofmotor cup assembly. Push out the motor cup assembly from the rear of the panel.e. Mount the replacement motor cup assembly in the panel using original screws. Torque screws to 0.29 mkg(25 +/- 1 Inch pounds).f. Reapply sealer to the inside and the outside of the motor cup assembly.ABCDEABCDEControllerConnector (EC) Drive ModuleConnector (SD)JumperTestConnector |
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