TM 5-6675-318-14
Table 4-24.
DIRECT/GENERAL SUPPORT TROUBLESHOOTING - Cont
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
18. NO KEYBOARD RESPONSE.
Isolate the problem by the substitution method using boards known to be good.
(a) Replace data entry and display board (paragraph 4 - 20 . 2) .
(b) Replace memory processor board (paragraph 4-20.2).
(c) Replace memory board (paragraph 4-20.2).
( d ) R e p l a c e k e y b o a r d ( p a r a g r a p h 4 - 2 0 . 4 ).
19. NO POSITION FIX CALCULATION BUT SATELLITE SIGNAL WAS ACQUIRED.
Step 1.
Check the reference oscillator frequency offset by entering code
56.
( a ) I f t h e r e f e r e n c e o s c i l l a t o r f r e q u e n c y i s w i t h i n 4 0 H z,
proceed to step 2.
NOTE
New oscillator must stabilize for 24 hours before making further checks.
(b) If the reference oscillator frequency exceeds 40 HZ, replace
t h e o s c i l l a t o r ( p a r a g r a p h 4 - 2 0 . 8 ).
Step 2.
Isolate the problem by substitution method using boards known to be
good .
(a) Replace memory board (paragraph 4-20.2).
(b) Replace the memory/processor board (paragraph 4-20.2).
4-200
