TM 9-6625-1753-14
C3
Table SAMPLE TABLE
Table 2-4. Oscilloscope Check Procedures-Continued
Step
Operation
Normal Indication
Corrective procedure
Step
Operation
Normal Indication
Corrective procedure
version 74-13A or Fig. 3-14, newer
version 74-13A).
1.
Check (Step Name)
Sequence and step name of the specific
Check normal sweep circuit of the de-
check.
laying sweep plug-in.
(OPERATION)
Sequential operations required to obtain
t. Adjust the FOCUS, ASTIG, and INTENSITY controls (39, 9, and 11) to (obtain a sharp horizontal trace line.
an indication.
A sharp trace line can be obtained.
a.
Adjust the PAT CORR control at the
b.
rear of the main frame.
(NORMAL INDICATION)
Normal system or circuit responses.
The trace line is alined with the CRT overlay.
(CORRECTIVE PROCEDURES)
Adjust the BEAM ROTATE control.
Adjustment listing if applicable.
2.
Check Calibration Signal
Reference to functional schematics.
a. Set the channel A VOLTS/DIV switch (1 or 58) fully counterclockwise to CAL.
A 4-division peak-to-peak square wave is present.
Center the waveform on the CRT with
Table 2-4. Oscilloscope Check Procedures
the POSITION control (5 or 56).
Adjust the GAIN ADJ control (51 or
76) if the square wave is other than 4
Step
Operation
Normal Indication
Corrective procedure
divisions in amplitude.
Adjust the SWP CAL control (22) if
Note 1. The numbers in parentheses are keyed to components located in figure 2-6.
the pulse repetition time (prt) is not
Note 2. An oscilloscope warm-up period of 20 minutes should precede these checks.
2.5 divisions (400-Hz line source) or
3.3 divisions (60-Hz line source).
1.
Check Normal Sweep.
Refer to the po wer supply functional
a. Set the INTENSITY control (11) fully counterclockwise.
schematic (figure 4-3).
b. Set the ASTIG control (9) to Midrange.
Check the low-voltage power supply on
c. Set the FOCUS control (39) to midrange.
the main frame.
d. Set the SCALE ILLUM control (38) to midrange.
Refer to the dual trace plug-in 76-02A
The power-on indicator lamp (40) illuminates.
or the dual trace plug-in 79-02A func-
e. Set the TIME/DIV switch (28) to 1 mSEC for 400-Hz line source; or 5 mSEC for 60-Hz line source.
tional schematic (figure 4-4 or 4-4.1,
f. Set the DELAYED SWEEP-PULL TO UNLOCK switch (26) to 1 mSEC for 400-Hz line source; or 5 mSEC for 60-
respectively).
Hz line source.
Check the input voltage attenuator cir-
g. Set the TIME/DIV sweep vernier control (24) fully clockwise (in the detent).
cuit in the dual trace plug-in (76-02A
h. Set the SOURCE switches (21 and 29) to LINE.
or 79-02A).
i. Set the COUPLING switches (20 and 30) to AC.
Refer to the delaying sweep plug-in
j. Unlock the DELAY VERNIER control (37), and set this control to 0 (window and dial).
k. Set the AUTO-NORM switch (33)(older version 74-13A) or NORMAL-AUTO-HF-RECUR switch (28.1)(newer
Check the normal sweep circuit of the
version 74-12A) to NORMAL.
delaying sweep plu g-in.
l. Set the LEVEL controls (14 and 36) to 0.
b. Set the channel A NORM-INVERT switch (52 or 75) to INVERT AC.
m. Set the DISPLAY LOGIC switch (12) to NORM.
A 4-division square wave is present.
n. Set the POSITION controls (5, 13, and 44)(or 13, 56, and 65) to midrange.
Refer to the dual trace plug-in func-
o. Set the NORM-INVERT switches (49 and 52) to NORM AC.
p. Set the VOLTS /DIV switches (1 and 45)(or 58 and 66) to any position except CAL.
c. Set the channel B VOLTS/DIV switch (45 or 66) to CAL and the MODE switch (7 or 60) to B (or CH2).
q. Set the VARIABLE controls (3 and 46)(or 59 and 67) to CAL (in the detent).
A 4-division square wave is present.
r. Set the MODE switch (7) to A, or MODE switch (60) to CH1.
Adjust the GAIN ADJ control (50 or
s. Rotate the INTENSITY control (11) cloc kwise.
70).
A horizontal trace line is present.
Adjust LEVEL control (36).
Adjust the POSITION controls (5 and
13).
Refer to the delaying sweep plug-in
functional schematic (Fig. 4-5, older
2-9
