Carrier 69NT40-541-300, Операция и обслуживание, Страница: 114 / 152

6 − 26 T − 318
Checking 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,
and the negative lead to pin B or TP − 9 of the control-
ler.
d. Turn ON the unit for 40 seconds, and watch the volt-
meter. There should be approximately 24 to 32 VDC
shown on pin A.
e. There should be zero volts on pin B.
f. After a short delay, the reading should rise to approx-
imately 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 be
checked 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
thorough, 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 con-
troller connectors as shown in Figure 6-31.
i. Connect the positive lead of the voltmeter to test con-
nector socket C and negative lead to socket B, and
run as before by resetting unit.
j. Repeat for sockets D and B.
A
B
C
D
E
A
B
C
D
E
Controller
Connector (EC)
Drive Module
Connector (SD)
Jumper
Test
Connector
Figure 6-31 Jumper Assembly
There should be approximately five volts DC on sockets
“C” and “D” (S1 and S2) when measured as above. If not
the connections or controller is faulty. If any of these pins
are not consistent, the connections or the controller is
suspect. Check and replace as required.
6.26.3 Servicing the eAutoFresh Drive System
To replace the Drive Motor Assembly:
a. Remove the bolts that secure the eAutoFresh Panel
(3, Figure 6-32) to the front of the unit. Reach in, cut
tie wrap, (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 of
motor cup assembly. Push out the motor cup as-
sembly 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.
g. Mount the upper & lower rails, slide plate and gasket
plate using original hardware. Apply thread sealant
and torque screws to 0.29 mkg (25 +/ − 1 Inch
pounds).
h. Mount grille assembly using original hardware. Apply
thread sealant and torque screws to 0.29 mkg (25 +/ −
1 Inch pounds).
i. Reconnect the motor connector.
j. Replace the bolts that secure the eAutoFresh Panel
to the front of the unit.
k. Carry out functional test. Refer to section 4.4.3 step
c.