TM 5-1260-206-34
Table 5-2.
DIC Troubleshooting Procedures - Continued
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Check that positive TTL pulse is present when correspond-
ing switch is pressed.
If not present, replace faulty printed circuit board.
Step 6.
Check that malfunction is corrected.
If not, refer faulty DIC to depot maintenance personnel.
2.
PUSHBUTTON INDICATORS NOT LIT
Remove top assembly. Connect multimeter between pin + and
Step 1.
pin - for suspect pushbutton. Check that +5 volts is
present.
If voltage is present, replace faulty switch.
If voltage is not present, do step 2.
Connect multimeter between P1 pin 15 (+) and pin 9 (-).
Step 2.
Check that +5 volts is present.
If voltage is present, replace faulty wire.
If voltage is not present, problem is in DAC or OMS
base plate wiring. Refer to chapter 3 or 4 and
perform continuity checks.
PUSHBUTTONS OR FOOTSWITCH DO NOT WORK
3.
Remove top assembly. Connect oscilloscope to pin 2 of
Step 1.
pushbutton switch in question or P1, pin 7 for footswitch.
(See figure 5-1.) Check for:
Negative TTL pulse for pushbutton switches.
Positive TTL pulse for footswitch.
If present, do step 5.
If not present, replace faulty switch or resistor.
(See table 5-4.)
5-4
Previous Page
