TM 11-5805-424-15/NAVSHIPS 0967-220-9010/TO 31W2-2G-41
7-7. Timing Tests
a. Test Equipment and Material.
(1) Test Modem, Low- Speed Wire Line MD-674(P)/G.
(2) Data analysis center, Stelma model DAC-6A.
(3) Electronic counter, Hewlett-Packard model 5233L.
(4) Oscilloscope, Hewlett-Packard model 140A with plug-ins 1405A and 1421A.
(5) Hookup wire.
b. Test Connection and Conditions.
(1) Remove the test MD-674(P)/G from its case, and install the repaired MD-674(P)/G in its place, or remove the appropriate plug-in module from the test
MD-674(P)/G, and install the repaired plug-in module in its place.
(2) Install Clock Module Group OA-8072/G (original or repaired) in the MD-674(P)/G.
(3) Connect the equipment as shown in figure 7-2.
(4) Strap, together, terminals TP4 and TP5 on PC assembly A1.
(5) Operate all POWER switches to the on position.
c. Procedure.
Step
Control settings
No.
Test equipment
Equipment under test
Procedure
Performance standard
PG-205A
1
BAUD RATE: As required.
a. Observe indication on 5233L.
a. 5233L should indicate frequency
BAUDS: As required.
ALARM: DISABLE.
equal to baud rate of equipment
Selector switch: SYNCBIT-
INPUT SELECT: DATA.
under test, 2%.
TIME.
PATTERN SELECTOR:
REVERSALS.
CHARACTER RELEASE:
b. Remove 5233L connections from
b. 5233L should indicate as in a above.
FREE RUN.
terminals 10 and 11, and connect
DISTORTION: OFF.
them to terminals 1 and 2.
37.5
c. Remove 5233L connections from
c. 5233L should indicate as in a above.
EXTERNAL:
1200
terminals 1 and 2, and connect
them to terminals 4 and 5.
JACK SIGNAL SELECTOR:
d. Remove 5233L connector from
d. 5233L should indicate as in a above.
LOW LEVEL.
terminals 4 and 5, and connect
them to terminals 7 and 8.
Electronic Counter 52331.
e. Observe both patterns on the 140A
e. Pattern should be of same fre-
oscilloscope.
quency but not necessarily in
FUNCTION: FREQUENCY A.
synchronism.
TIMEBASE-MULTIPLIER:
f. Pattern should appear synchronous,
6
1uS10 .
nections from terminals 1 and 2
with all data (input A) and
SAMPLE RATE: Midposition.
(TB2) and connect them to
timing (input B) transitions in
COM-SEP-CHECK: SEP.
terminals 4 and 5.
alignment.
7-7
