TM 9-4120-360-14
c. Heater and Compressor Relays. (K1, K2) Check
continuity of
terminals X1-X2. If
continuity is
indicated.
apply 26-28 volts dc to terminals X1-X2, and check continuity of terminals A1-A2, B1-B2 and C1-C2. Continuity
should exist. If it does not, replace the relay.
d. Two-speed Motor Relays (K4, K5 Check continuity of terminals. X1-X2, A2-A3, B2-B3, C2-C3 and
)
D2-D3. All should indicate continuity. Apply 26-28 volts, dc. to terminals X1-X2, and check continuity of terminals
A1-A2, B1-B2, C1-C2 and D1-D2. All should indicate continuity. If continuity requirements are not met, replace the
day.
e. Time Delay Relay. (K3). In
addition to
your usual continuity testing equipment, you will need a clock or
watch on which seconds can be read for this test. Proceed as follows:
(1) With the time delay relay disconnected, check continuity between terminals 2 and 4.
Continuity should
be indicated.
(2) Semi-permanently connect the test prods to terminals 2 and 3. While observing the clock or watch, apply
a source of 26-28-volt dc power to the dc terminals of the time delay relay, making sure to apply positive (+) to positive
and negative (-) to negative.
(3) Continuity should be indicated after a delay of 19 to 31 seconds. If the delay is not within limits, or if
continuity requirements are not met, replace the time delay relay.
f. Transformer (T) Check
continutiy of
terminals H1-2 and X1-X2. Continuity should exist. Check
continuity
.
between H1 and casing or common ground, and between X-1 and casing or common ground. Continuity should not exist.
Connect the test leads of a voltmeter to terminals X1-X2, and apply 208 volts, 50/60 hertz to terminals H1-H2. The
voltmeter should indicate 30 3 volts (rms). If transformer does not meet both continuity and voltage requirements,
replace it.
g. Terminal Boards (TB1, TB2). Inspect the terminal boards for obvious damage and evidence of electrical
,
failure. Check continuity across each pair of terminals. Replace if damaged or if continuity requirements are not met.
h. Electrical Receptacles. Inspect for deformation. damaged threads and cracked or broken wafers. Check
continuity from each pin of the connector to the terminal end of its associated wire lead. Continuity should exist. Check
continuity from each pinto the shell of the connector, Continuity should not exist. Replace the receptacles if they indicate
damage. or if continuity requirements are not met.
i. Rectifier (CR 1) With an
ohmmeter set at
2000 ohms, check for continuity between each terminal and the
.
mounting stud. No continuity should exist. Connect 27-33 volts, 50/60hertz to ac terminals 1 and 4. Using a dc voltmeter,
Check terminals 2 (-) and 3 (+) for 26-32 volt dc output. Replace the rectifer if both the continuity and the voltage
requirements are not met.
j. Diode Semiconductor (CR2) Apply the test leads of an ohmmeter to the leads of the diode, and observe the
.
meter. Then reverse the leads. and again observe the meter. The meter should indicate resistance in one direction. and
show no indication in the other. If the ohmmeter indicates resistance in both directions, the diode is short-circuited; if
there is no reading in either direction, the circuit is open. Replace the diode if short- or open-circuit exists.
5.11. Assembly
Position components over studs or anchor nuts, as required, and secure with the appropriate mounting hardware. Install
wiring harness receptacles in mounting holes, and secure with four screws, washers and self-locking nuts in each.
Connect terminals of wiring harnesses to components as required. (See wiring diagram, figure FO-1 for proper
connections.)
5-6