Organizational Troubleshooting (continued)
TEST OR INSPECTION
Check dc mode operation.
and perform operational check.
If dc mode operation is not normal, go to step 7 of
AC OVER VOLTAGE, OR AC UNDER FREQUENCY INDICATOR LIT.
Set AC POWER switch to RESET, then return to ON.
If all AC warning (red) indicators did not turn off
(momentarily), go to step 2.
If all AC warning indicators are now off, continue operation
if no other abnormal indications are observed.
If same warning indicator (AC OVER VOLTAGE or UNDER FRE-
QUENCY) lights again, the most probable cause of fault is
GCU. The generator is also a possible cause of fault,
especially if COMPT/GEN HI TEMP indicator is illuminated.
visor. Perform operational check.
Test AC POWER switch 1S10 (malfunction 79).
If switch tests good, do step 3.
Shut down engine and disconnect battery. Lower control panel (para-
graph 4-24.a), and remove battery charger access cover. Disconnect
main harness connector P7 from control panel connector J7, and
disconnect harness connector P12 (36, figure 4-38) from GCU. Check
for continuity between P7-13L and P12-S, and between J7-13R and 1S10-
a. If no continuity replace defective wire (X20A20 or X20B20).