TM 3-6665-302-34
(7) Perform procedure in M43 detector unit
Figure 3-4. M43 detector unit troubleshooting chart.
(Located in back of manual)
troubleshooting chart (fig. 3-4). After comple-
tion of repairs, repeat figure 3-4.
Figure 3-5. Horn circuit troubleshooting chart.
(8) Perform M74 test set shutdown proce-
(Located in back of manual)
dures.
Figure 3-6. Electronic module trouble shooting chart.
g. Electronic Module Assembly (1A2A4). Per-
(Located in back of manual)
form the following procedures to test the elec-
tronic module assembly.
Figure 3-7. Pump assembly troubleshooting chart.
(Located in back of manual)
(1) Prepare M74 test set for use (TM 3-
6665-260-14).
Figure 3-8. Meter circuit troubleshooting chart.
(2) Connect 24-volt dc power source to the
(Located in back of manual)
M74 test set.
Figure 3-9. Motor control voltage circuit troubleshooting
(3) Set AMMETER switch to SHUNT
chart.
position.
(Located in back of manual)
(4) Set METER SELECTOR switch to
SUPPLY position. METER M1 must indicate be-
Figure 3-10. Reset circuit troubleshooting chart.
tween 26 and 36 volts.
(Located in back of manual)
(5) Position and hold AMP MODE switch
Figure 3-11. Inlet heater troubleshooting chart.
to RESET for about 5 seconds; then release.
(Located in back of manual)
(6) Plug electronic module assembly into
1A2A4 TEST SOCKET.
Pneumatic system troubleshooting chart.
Figure 3-12.
(Located in back of manual)
(7) Set METER SELECTOR switch to
AMP TEST position.
Pneumatic system troubleshooting chart.
Figure 3-12.
(8) Perform procedures in the electronic
(Located in back of manual)
module assembly troubleshooting chart (fig. 3-
6).
Figure 3-13. Cold temperature operation troubleshooting
chart.
h. Pump Assembly (1A2A1). Perform the fol-
(Located in back of manual)
lowing procedures to test a pump assembly.
Figure 3-14. Flow rate meter troubleshooting chart.
(1) Prepare the M74 test set for use (TM
(Located in back of manual)
3-6665-260-14).
(2) Remove cover from pump assembly
Figure 3-15. Zero adjust circuit troubleshooting chart.
(Located in back of manual)
(3) Inspect for fluid in unit. Clean with
distilled water if necessary.
nect positive lead to REMOTE terminal nearest
(4) Inspect tubing and rollower, replace if
HORN-Battery TEST knob and negative lead to
necessary (para 3-28 and 3-34).
other REMOTE terminal.
(5) Connect a 24-volt dc power source to
(1) Set M74 test set AMMETER switch to
the M74 test set.
SHUNT.
(6) Connect PRESSURE TEST tube (4,
(2) Set METER SELECTOR switch to
SUPPLY.
(7) Turn M74 test set PRESSURE LOCK
(3) Raise and secure M74 test set flow rate
knob fully counterclockwise.
meter bracket in vertical position.
(8) Connect bellows and pump to PRES-
(4) Turn FLOW ADJUST valve and PRES-
SURE PORT.
SURE LOCK valve fully counterclockwise.
(9) Raise and secure M74 test set flow rate
(5) Connect 24-volt dc power source to POW-
meter bracket in vertical position.
ER connector or to POWER binding posts.
(10) Perform procedures in the pump as-
(6) Meter M1 must indicate between 24 and
sembly troubleshooting chart (fig. 3-7).
36 volts.
