DIRECT SUPPORT MAINTENANCE
This chapter describes the maintenance opera-
Direct support maintenance personnel are au-
tions authorized to be performed by direct sup-
thorized to spot paint all surfaces that are chip-
port maintenance personnel.
ped, scratched, or scraped.
Refer to TB SIG 222 for instructions
Mask printed matter before painting.
Tools and Equipment
Use green, lusterless enamel paint, shade num-
Refer to TM 3666522512 for a list of tools
ber 34087 (Fed Std 595).
and equipment required for maintenance.
Section Il. M43 DETECTOR UNIT TROUBLESHOOTING
This section provides instructions for trouble-
shooting the M43 detector unit at the direct
Once the detector unit assembly is re-
support maintenance level.
moved from the bottom case assembly,
do not reassemble the two assemblies
a. Troubleshooting Illustrations. The following
until instructed to do so.
illustrations are provided as aids to troubleshoot-
ing and maintenance of the M43 detector unit,
a. Prepare fresh solution and install reservoir
assembly and fresh air filter in detector unit
M43 detector unit pheumatic system.
assembly (TM 3666522512).
the M43 detector unit assembly.
J4 (contacts in the bottom case assembly) (2,
M43 detector unit chassis assembly.
Resistance must be 63 to 73 ohms.
the M43 detector unit case top assembly.
b. Troubleshooting Charts. Figure 3-3 de-
c. Prepare M74 test set for use (TM 3-6665
scribes the use of troubleshooting charts, figures
3-4 through 3-15. The troubleshooting charts
d. Install rainshield adapter in AIR INLET
provide systematic procedures for isolating
assembly (TM 36665-22512 ). Set M43 detector
troubles in the M43 detector unit. The trouble-
unit AIR INLET to CLOSED. Attach VACUUM
shooting charts also provide systematic procedures
TEST tube of M74 test set to rain shield adapter.
for testing after repair.
Remove M43 detector unit AIR OUTLET cap
c. M74 Test Set. Prepare the M74 test set for
and 24 VDC INPUT cover. Press in and release
use by following the preliminary procedures in
TM 3-6665-260-14. After using the M74 test set,
perform the shutdown procedures in TM 3-
e. Press in ZERO ADJUST knob, rotate fully
clockwise, and release.