(7) Place POWER DC switch ON. RESULT BOOST
PRESS OFF green light shall come on. If not, check the fol-
lowing
(a) Replace lamp.
(b) Perform continuity checks on indicator and associated
wiring (FO-1). Replace indicator light or repair/replace wiring
(FO-2).
(8) Remove jumper.
(9) Turn POWER DC switch OFF.
h. Variable Current Supply Test.
(1) Connect cable W2 (supplied with test box) to connec-
tor J3.
(2) Connect digital multimeter mA terminal to pin 2 of SAS
ACTUATOR end cable W2, and LOW terminal to pin 1, using
two leads.
(3) Set TRIM COIL SELECT switch to BOTH.
(4) Set AC POWER switch to ON.
TM 55-4920-414-13&P
(5) Adjust CURRENT CONTROL cw toward INCR un-
til valve current meter indicates – 10.00 mA. If digital mul-
timeter does not indicate between –9.50 and -10.50, perform
the following adjustments
(a) Set AC POWER switch to OFF.
(b) Remove T1 from protective case.
(C) Set AC POWER switch to ON.
(d) Adjust CURRENT CONTROL until digital mul-
timeter indicates 0.000.
(e) Adjust R15 (under circuit board, right front) until
valve current meter indicates 00.00 with flashing polarity.
(6) If adjustment cannot be made above perform
troubleshooting Table 4-8, Trouble No. 4, FO-3 and FO-1 as re-
quired. When repairs are completed repeat para 4-23h (5), (7)
and (8) above.
(7) Set AC POWER switch to OFF.
(8) Repeat technique of (2) through (5) above at connection
and switch positions listed in Table 4-7. Digital multimeter will
indicate within limits specified. If not, perform (6) above.
Table 4-7. Valve Current Meter
Digital Multimeter
Connections to SAS
ACTUATOR end of
TRIM COIL SELECT
Digital Multimeter
Cable W2
switch positions
Indications (ma)
mA
LOW
Min
Max
Pin 2
Pin 1
1
-9.50
-10.50
Pin 2
Pin 1
2
0.0
0.0
Pin 2
Pin 1
BOTH
+9.50
+ 10.50
Pin 4
Pin 3
BOTH
+9.50
+ 10.50
Pin 4
Pin 3
BOTH
-9.50
-10.50
NOTE:
Adjust CURRENT CONTROL toward DECR until valve current meter indicates + 10.00 mA.
Adjust CURRENT CONTROL toward INCR until valve current meter indicates – 10.00 mA.
4-23
