Tektronix 422, Instruction Manual

Page: 117 / 213

Performance Check/Calibration—Type 422 AC-DC
TABLE 5-4
Channel 2 VO LTS/DIV Switch Compensation
Channel 2
Adjusted fo r optimum
VO LTS/DIV Attenuator
Switch setting
compensated Square corner Flat top
.05 + 1 C l 12
.02
Check If out o f tolerance.
.01 Check
com prom ise setting
at .01, .02 and .05
fo r best overall re-
sponse.
Remove external 10X attenuator from generator
.1 - 2 C103C C103B
.2 - 4 C104C C104B
.5 - 10 C105C C105B
Remove 50-ohm termination
1 Check If out o f tolerance,
com prom ise setting
at .5, 1 and 2 fo r best
overall response.
2 Check
5
+100 C106C C106B
10 Check
If out of tolerance,
com prom ise setting
at 5, 10 and 20 for
best overall response.
20 Check
c. Set the square-wave generator fo r a five-division dis­
play at 100 kilohertz in the fast-rise mode.
d. CHECK—CRT display fo r optim um square-wave
response w ith aberrations not to exceed +0.15 or —0.15
division, w ith total peak-to-peak aberrations not to exceed
0.15 division (within +3% or —3% w ith total peak-to-peak
aberrations w ithin 3%; (see Fig. 5-18A).
e. ADJUST—R237, C237, L245 and L255 in given
o rd e r f o r optim um square-wave response (use low-
capacitance screwdriver for C237 and tuning tool for
L245-L255). Fig. 5-18B shows the location o f these adjust­
ments; L245 and L255 can be adjusted through the access
holes in the rear panel o f the indicator. Since these adjust­
m en ts in te ra c t, readjust until optimum square-wave
response is obtained.
f. Set the vertical Mode switch to CH 2.
g. Connect the square-wave generator fast-rise + output
connector to the INPUT 2 connector through the GR to
BNC adapter, 18-inch 50-ohm BNC cable and the 50-ohm
BNC termination.
h. Set the square-wave generator for a five-division dis­
play at 100 kilohertz in the fast-rise mode.
i. CHECK—CRT display fo r optimum square-wave
response similar to Channel 1 response.
j. ADJUST—If necessary, compromise the adjustment of
R237, C237, L245 and L255 fo r best response for both
checks d and i.
k. Disconnect all test equipment.
28. Check Upper Vertical Bandwidth Lim it of
Channel 1 and 2
a. Change the follow ing control settings:
Vertical Mode CH 1
T IM E /D IV .5 ms
X I 0 MAG Pushed in
r
/
L245
R237
Delay Line Comp
C237
R
Freq Comp
it
Fig. 5-18. (A) Typical CRT display showing correct high-frequency
compensation, (B)
location of high-frequency compensation
adjustments (Vertical Switching and Output Amplifier board).
5-23