Tektronix 422 - Page 127

Performance Check/Calibration—Type 422 AC-DC
h. ADJUST—C527 (see Fig. 5-27) for one marker each
division (use low-capacitance screwdriver).
i. Repeat parts c through h of this step until optimum
timing is obtained.
50. Check Normal Sweep Timing Accuracy
a. Push the X10 MAG switch in.
CAUTION
To prevent permanent damage to the CRT phosphor
at slow sweep rates position the baseline of the
marker display below the viewing area.
b. CHECK—Using the TIME/DIV switch and time mark
generator settings given in Table 5-5, check sweep timing
within 0.24 division (within 3%) over the middle eight divi
sions of the display. Adjust the LEVEL control as necessary
to obtain a stable display.
51. Check Magnified Sweep Timing Accuracy
a. Pull the X10 MAG switch.
b. CHECK—Using the TIME/DIV switch and time-mark
generator settings given in Table 5-6, check magnified
timing within 0.4 division (within 5%) over the middle eight
divisions of the total magnified sweep length.
c. Disconnect all test equipment.
TABLE 5-5
Normal Sweep Timing
TIME/DIV switch
setting
Time-mark
generator output
CRT display
(markers/division)
.5 [is 0.5 microsecond
1
1 [is 1 microsecond
1
2 [is 1 microsecond
2
5 [is 5 microsecond 1
10 [is 10 microsecond
1
20 [is 10 microsecond
2
50 [is 50 microsecond
1
.1 ms 0.1 millisecond
1
.2 ms 0.1 millisecond
2
.5 ms 0.5 millisecond
1
1 ms 1 millisecond
1
2 ms 1 millisecond
2
5 ms 5 millisecond
1
10 ms 10 millisecond
1
20 ms
10 millisecond
2
50 ms 50 millisecond
1
.1 s 0.1 second
1
,2 s 0.1 second 2
,5 s
0.5 second
1
52. Check Gate Output Signal
a. Change the following control settings:
TRIGGERING Source CH 1 & 2
TIME/DIV 1 ms
X I0 MAG Pushed in
b. Connect the GATE OUT connector to the input of
the test oscilloscope with a 42-inch BNC cable.
c. Set the test oscilloscope for a vertical deflection of
0.1 volt/division and a sweep rate of two milliseconds/
division.
d. CHECK—Test oscilloscope for five divisions or
greater amplitude (0.5 volt or greater in amplitude; see Fig.
5-28). Gate duration should be between 5.2 and 6.05 divi
sions (10.4 to 12.1 times the TIME/DIV switch setting).
e. Disconnect the test oscilloscope.
53. Check Chopped Operation
a. Change the following control settings:
Vertical Mode CHOPPED
TIME/DIV 1 jus
b. Position the traces about four divisions apart with the
Channel 1 and 2 POSITION controls.
TABLE 5-6
Magnified Sweep Timing Accuracy
TIME/DIV switch
setting
Time-mark
generator output
CRT display
(markers/division)
.5 |ls 50 nanosecond
1
1 [is .1 microsecond 1
2 [is .1 microsecond 2
5 [is .5 microsecond
1
10 [is 1 microsecond
1
20 [is 1 microsecond 2
50 [is
5 microsecond
1
.1 ms 10 microsecond
1
.2 ms
10 microsecond 2
.5 ms
50 microsecond 1
1 ms
.1 millisecond
1
2 ms
.1 millisecond 2
5 ms
.5 millisecond 1
10 ms
1 millisecond 1
20 ms
1 millisecond 2
50 ms
5 millisecond 1
.1 s
10 millisecond 1
.2 s
10 millisecond 2
.5 s
50 millisecond 1
5-33