Tektronix 422, Instruction Manual

Page: 115 / 213

Performance Check/Calibration—Type 422 AC-DC
c. CHECK—Set the Channel 1 Input Coupling switch to
DC; trace shift should be negligible.
d. Set the vertical Mode switch to CH 2.
e. Position the trace to the center horizontal line with
the Channel 2 POSITION control.
f. CHECK—Set the Channel 2 Input Coupling switch to
DC; trace shift should be negligible.
24. Check Alternate Operation
a. Set the vertical Mode switch to A LT.
b. Position the traces about tw o divisions apart.
c. Turn the T IM E /D IV switch throughout its range.
d. CHECK—Trace alternation between Channel 1 and 2
at all sweep rates. A t faster sweep rates, alternation is not
apparent; instead display appears as tw o traces on the
screen.
25. Check/Adjust Channel 1 Volts/Division Switch
Compensation
a. Change the following control settings:
CH 1 and 2 VO LTS/DIV .05
Vertical Mode CH 1
T IM E /D IV ,2 ms
b. Connect the square-wave generator (Type 106) high-
amplitude output connector to the INPUT 1 connector
through the GR to BNC adapter, 18-inch 50-ohm BNC
cable, 10X BNC attenuator, 50-ohm BNC term ination and
the 33 pF RC normalizer, in given order.
c. Set the square-wave generator fo r a four-division dis­
play at one kilohertz in the high-amplitude mode.
d. CHECK—CRT display at each Channel 1 VO LTS/
DIV switch setting as given in Table 5-3 fo r optimum
square corner and fla t top w ithin +3% or —3% w ith total
peak-to-peak aberrations
not to exceed 3% (see Fig.
5-17A). Remove the 10X attenuator and 50-ohm termina­
tio n as given in Table 5-3. Readjust the generator output
amplitude at each setting to maintain a four-division dis­
play, or to provide maximum vertical deflection in the 20
position.
e. ADJUST—Channel 1 VO LTS/D IV switch compensa­
tion as given in Table 5-3 (use low-capacitance screwdriver).
First adjust fo r optimum square corner and then fo r o p ti­
mum flat top. Remove the 10X attenuator and 50-ohm
term ination as given in Table 5-3 and readjust the generator
o utput amplitude at each setting to maintain a four-division
display, or to provide maximum deflection in the 20 posi­
tion. Fig. 5-17B shows the location of the variable
capacitors.
TABLE 5-3
Channel 1 VO LTS /D IV Switch Compensation
Channel 1
VO LTS/DIV
switch setting
Attenuator
compensated
Adjusted for c
Square corner
ptimum
Flat top
.05 t 1
—
C12
.02
Check If out o f tolerance,
compromise setting
at .01, .02 and .05
fo r best overall re­
sponse.
.01 Check
Remove external 10X attenuator from generator
.1 - 2 C3C C3B
.2
- 4
C4C C4B
.5
- 10 C5C
C5B
Remove 50-ohm termination
1 Check If out o f tolerance,
compromise setting
at .5, 1 and 2 for
b e s t o v e ra ll re­
sponse.
2 Check
5
-FI 00 C6C C6B
10
Check If out o f tolerance,
compromise setting
at 5, 10 and 20 for
b e s t o v e r a ll re­
sponse.
20 Check
26. Check/Adjust Channel 2 Volts/Division
Switch Compensation
a. Set the vertical Mode switch to CH 2.
b. Connect the square-wave generator high-amplitude
output connector to the INPUT 2 connector through the
GR to BNC adapter, 18-inch 50-ohm BNC cable, 10X BNC
attenuator, 50-ohm BNC term ination and the 33 pF RC
normalizer, in given order.
c. Set the square-wave generator fo r a four-division dis­
play at one kilohertz in the high-amplitude mode.
d. CHECK—CRT display at each Channel 1 VO LTS/
DIV switch setting as given in Table 5-4 fo r optim um
square corner and fla t top w ithin +3% or —3%, w ith total
peak-to-peak aberrations not to exceed
3% (see Fig. 5-17A).
Remove the 10X attenuator and 50-ohm term ination as
5-21