TM 55-4920-428-13
r. Provide an out-of-phase input signal to the SAS 1 self-demodulators as follows:
(1) Set the power switch to OFF.
(2) Disconnect the test aid in-phase wire from receptacle 1-4.
(3) Connect the test aid out-of-phase wire to receptacle pin J1-4.
(4) Connect No. 1 multimeter to the test aid out-of-phase wire and the moving contact of the
variable resistor.
(5) Set the power switch to ON.
s. Repeat steps k through p. The meter indications shall be as stated except the dc voltage indica-
tions shall be opposite in polarity.
4-48. SAS 1 Cross-Feedback and Metering Circuits Test. This test ensures the SAS 1 cross feed-
back and metering circuits function as required. (See FO-1 for J1 pin pattern.)
NOTE
When performing this test, make sure the test aid and multimeters are
as follows:
1. The primary winding of the test aid transformer is connected to
receptacle pins J1-1 and J1-2. See fig. 4-3.
2. No. 1 multimeter is set to measure ac volts,
3. No. 2 multimeter is connected to SAS 1 EXTERNAL METER + and
- jacks, set to measure dc.
a. Provide an in-phase input signal to the SAS 1 cross demodulators as follows:
(1)
(2)
(3)
(4)
(5)
(6)
resistor.
b. Set
Set the power switch to OFF.
Disconnect jumper wire from receptacle pins J1-13 and J1-14.
Disconnect the test aid out-of-phase wire from receptacle 1-4.
Connect a jumper wire to receptacle pins J 1-3 and J 1-4.
Connect the in-phase wire to receptacle pin J 1-14.
Connect No. 1 multimeter to the test aid in-phase wire and the moving contact of the variable
the power switch to ON.
c. Press SAS 1 FEEDBACK SELECT switch to CROSS.
d. Set SAS 1 EXTERNAL METER SELECT and SAS 1 LINK TEST switches to CROSS FDBK.
Do not press meter X10 pushbutton switch unless the associated null
meter indicates less than 5 microampere. Otherwise, the null meter
can be damaged.
4-20
