ARMY TM 5-6675-308-34
MARINE CORPS TM 08837A-34/2
Table 4-19. PS Testing and Troubleshooting Continued
Malfunction
Test procedure
Normal indication
indication/corrective action
Switch
Setting
POWER SUPPLY
OFF
FLAG
OFF
COMP PS
2b. Set CB1 and CB2 circuit breakers to off
2c. Turn on external +28V power source
and adjust to +28V ( l)V
2d. Turn on external O to +40V power source
and adjust to +0.5 ( 0 .25)V. Adjust the
current limit for 5 to 7 amps
2e. Set switches in order as follows:
Switch
Setting
INPUT POWER PSTS ON
POWER SUPPLY
ON
TEST SET
MODE
NO LOAD
INPUT POWER UUT ON
2f. Set PS battery and vehicle CB1 and CB2 to
ON. Check that fan is disconnected from J6
2g. Connect DVM test leads to POWER
SUPPLY PWR IN and PWR RTN test jacks
2h. Slowly increase O to +40V external power
Current drawn from O to +40V If current is greater than 1 amp indica-
extemal power source is less
source to +5V or 5 amp current limit.
ting a short, perform subroutine 1,
than 1 amp
If no current limit occurs, continue
then repeat steps 2a thru 2h. If cur-
increasing voltage to +24 (~0 .5)V at
rent is still greater than 1 amp, perform
POWER SUPPLY PWR IN and PWR RTN
subroutine 2 and recheck step 2h
test jacks
PS ON indicator lights. Cur-
2i. Press POWER SUPPLY ON switch
Use oscillsocope to determine which
rent drawn from O to +40V
particular output is missing when the
external power source is
switch is recycled. Look for outputs
1 to 6 amps
in order of +14V (+14V is on +INV
DR jack), +28V, -28V, +17V, 400-Hz
sinewave, 400-Hz square wave by
selecting proper FUNCTION switch
positions
4-111
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