TM 5-4220-225-14
SECTION IV. UNIT TROUBLESHOOTING
Paragraph
Page
4-8
General ................................ ................................ ................................ ................................ ......... 4-3
4-9
Unit Troubleshooting ................................ ................................ ................................ ..................... 4-3
4-8. General. This section contains troubleshooting and corrective action procedures authorized at the unit
maintenance level (see appendix B, MAC).
4-9. Unit Troubleshooting . Refer to the symptom index to locate the troubleshooting procedure for the observed
malfunction. Table 4-1 lists malfunctions that may occur during operation or maintenance of the MK12 SSDS. Tests,
checks, inspections, and corrective actions should be performed in the order listed. If a malfunction beyond the scope of
unit maintenance is discovered, refer the malfunction to the next higher level of maintenance.
NOTE
This table is not intended to cover every possible symptom, but is rather a list of the more
frequent problems and some of their causes and are presented in the order they are most
likely to occur.
SYMPTOM INDEX
Symptom
Page
1. Loss of communication, all divers ................................ ................................ ................................ ................. 4-4
2. Loss of communication, one diver ................................ ................................ ................................ ................. 4-4
3. Loss of communication between divers ................................ ................................ ................................ ......... 4-4
4. Weak or intermittent sending and receiving, one diver ................................ ................................ .................. 4-5
5. Topside does not receive one diver or reception is weak or intermittent................................ ........................ 4-5
6. One diver does not receive topside ................................ ................................ ................................ ............... 4-6
7. Vacuum test does not meet requirements ................................ ................................ ................................ ..... 4-6
8. Reduced airflow................................ ................................ ................................ ................................ ............. 4-7
9. Unable to increase the air flow ................................ ................................ ................................ ...................... 4-8
10. Excessive or uncontrollable flow ................................ ................................ ................................ ................... 4-8
11. Improper helmet P ................................ ................................ ................................ ................................ ........ 4-9
12. Leak in viewport assembly ................................ ................................ ................................ ............................ 4-10
13. Leak in adapter assembly ................................ ................................ ................................ ............................. 4-10
14. Leak at supply valve mounting ................................ ................................ ................................ ...................... 4-10
15. Leak at exhaust valve ................................ ................................ ................................ ................................ ... 4-11
16. Leak between the base and upper breach ring................................ ................................ .............................. 4-11
17. Leakbetween shellandbase ................................ ................................ ................................ ........................... 4-11
18. Relief Valve will not lift ................................ ................................ ................................ ................................ . 4-11
19. Relief valve will not re-seat ................................ ................................ ................................ ........................... 4-12
4-3
