TM 55-4920-429-13
d. Test the circuits of SIGNAL SEL 2 switch as follows: When ac or dc input signals are required,
connect the power supply across the receptacle pins listed below. Connect the digital multimeter across
The output of the power supply. STATUS lights shall be as listed below. (See FO-8 for connector pin
patterns.)
INPUT
SIGNAL SELECT 2
SIGNAL
RECEPTACLE
STATUS
STATUS
WITCH POSITION
CONDITION
PINS
ALT
BLT
RADAR ALT VALID
4 Vdc
J3-LL(+)
ON
OFF -
J3-AA
.
3 Vdc
Same
OFF
OFF
2 Vdc
Same
OFF
OFF
Open Ckt
Same
OFF
ON
RADAR ALT SELF
4 Vdc
J3-z(+)
ON
OFF
TEST GO
&
J3-AA
3 Vdc
Same
OFF
OFF
2 Vdc
Same
OFF
OFF
Open Ckt
Same
OFF
ON
L ROLL BEEP
TRIM ON
R ROLL BEEP
TRIM ON
VERT GYRO VALID
12 Vac
J3-FF (line)
ON
OFF
J3-AA
10 Vac
Same
OFF
OFF
2 Vac
Same
OFF
OFF
Open Ckt
Same
OFF
ON
12 Vac
J3-GG (line)
ON
OFF
J3-AA
10 Vac
Same
OFF
OFF
2 Vac
Same
OFF
OFF
Open Ckt
Same
OFF
ON
1.5 Vdc
J3-R(+)
ON
OFF
&
J3-AA
Open Ckt
Same
OFF
ON
Shorted
Same
ON
OFF
to gnd
HYD PRESSURE
1.5 Vdc
J3-a(+)
OFF
OFF
FULL
J1-C
Open Ckt
Same
OFF
ON
Shorted
Same
ON
OFF
BIT ENABLE STOP
to gnd
(return)
1.5 Vdc
J3-B(+)
OFF
OFF
&
J3-AA
Open Ckt
Same
OFF
ON
Shorted
Same
ON
OFF
to gnd
e. Disconnect the dc power supply.
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