TM 55-4920-413-13&P
Table 4-5. Troubleshooting Lamp Test Circuit (AVIM).
NOTE
Before performing troubleshooting, remove oil pressure (A2) board and reconnect using extender board.
Trouble
Probable Cause
Remedy
l15vac Indicator
F1 Fuse (2 amp) S1, T4, DS1
Replace defective components
lamp does not light
FO-5
28vdc Indicator
F2 Fuse (8 amp) S1, 330 ohm
Replace defective components
lamp does not light
330 ohm resistor 2W, DS2
FO-5
Low Oil Press NO 1 and NO 2
DS5/DS6
Replace defective components,
Lamps do not light
CR8/CR7
Figure 4-12, FO-4 and FO-5
High Oil Temp NO 1 and NO 2
DS7/DS8
Replace defective components,
lamps do not light
CR6/CR5
Figure 4-12, FO-4 and FO-5.
Engine Out NO 1 and NO 2
DS9/DSl0
Replace defective components,
do not light
CR4/CR3
Figures 4-12, FO-4 and FO-5
Lamp Supply Overload NO 1
DS3/DS4 S19,
Replace defective components,
and NO 2 do not light
CR12/CRll
Figures 4-12, FO-4 and FO-5
Low Rotor SPD does not light
DS1l
Replace defective components,
CR2
Figures 4-12, FO-4 and FO-5
All Indicator Lamps do not light
Lamp Test
Replace defective components,
Switch S8
Figures 4-12, FO-4 and FO-5
INTEGRAL LIGHTING INT
8 amp Fuse (F3)
Replace defective components,
Position indicates no vac
S39, T4
Figure FO-5
b. Power Supply Circuit (Input Voltage to A1 Board).
(1) Set all Power to OFF.
(2) Remove power supply board (A1) Figure 4-3 and recon
nect, using extender board.
(3) Connect digital voltmeter positive to loop 2 and nega-
tive to loop 8 on extender board, using two leads.
(4) Observe that ON-OFF-SIM ONLY switch is set to
SIM ONLY and set equipment POWER is ON. Digital volt-
meter will indicate between 21 and 27 vac. If not, perform
Troubleshooting Table 4-6.
(5) Disconnect lead from loop 2 and connect to loop 4. Dig-
ital voltmeter will indicate between 21 and 27 vac. If not, per-
form Troubleshooting Table 4-6.
(6) Disconnect lead from loop 4 and connect to loop 29 and
disconnect negative lead from loop 8 and connect to loop 43.
Digital voltmeter will indicate between 7 and 9 vac. If not, per-
form Troubleshooting Table 4-6.
(7) Disconnect lead from loop 29 and connect to loop 53 and
disconnect negative lead from 43 and connect to loop 49. Digi-
tal voltmeter will indicate between 7 and 9 vac. If not, perform
Troubleshooting Table 4-6.
(8) Disconnect lead from loop 53 and connect to loop 7 and
disconnect negative lead from loop 49 and connect to loop 11.
Digital voltmeter will indicate between 23 and 29 vac. If not,
perform Troubleshooting Table 4-6.
c. Power Supply Circuit (Voltage Output A1 Board).
(1) Connect digital voltmeter positive lead to loop 47 and
negative lead to loop 63. Digital voltmeter will indicate between
4.9 and 5.1 vdc. If not, perform Troubleshooting Table 4-6.
(2) Disconnect leads from loops 47 and 63. Connect digi-
tal voltmeter positive lead to loop 23 and negative lead to loop
27. Digital voltmeter will indicate between 4.9 and 5.1 vdc. If
not, perform Troubleshooting Table 4-6.
(3) Disconnect leads from loops 23 and 27. Connect digi-
tal voltmeter positive lead to loop 5 and negative lead to loop
14. Digital voltmeter will indicate between 14 and 16 vdc. If not,
perform Troubleshooting Table 4-6.
(4) Disconnect positive lead from loop 5 and connect to
loop 3. Digital voltmeter will indicate between -14 and -15
vdc. If not, perform Troubleshooting Table 4-6.
(5) Disconnect positive lead from loop 3 and connect to
loop 1, digital voltmeter will indicate between 33 and 41 vdc.
If not, perform Troubleshooting Table 4-6.
4-7
