Check Vertical Linearity; Adjust Vertical High-Frequency; Check Vertical Amplifier Bandwidth - Tektronix 7603 Instruction Manual

Calibration-7603/R7603 Service
f. Set the VERT MODE switch to RIGHT .
g. CHECK-Deflection between the second and eighth
traces should be the same as part d ±1%.
h. ADJUST-If necessary, re-adjust R447 for correct
tolerance in both parts d and h.
14 . Check Vertical Linearity
a. Remove the mainframe
standardizer calibration
fixture. Install the 7A15A in the left vertical compartment
and connect a 0.4 volt square wave signal from the
CALIBRATOR out jacks. Set the VERT MODE switch to
Ieft.
b. Set the 7A1 5A Volts/Div switch to 0.2 volt/division .
Adjust the position control to keep the display centered on
the graticule and adjust the Variable Volts/Div control if
needed for a two division display.
c. CHECK-Position the two divisions of display verti-
cally and check for not more than 0.1 division of
compression or expansion anywhere within the graticule
area . Remove the 7A15A and install the mainframe
standardizer calibration fixture.
15. Adjust Vertical High-Frequency Compensation
a. Set the calibration fixture Test switch to Vert or
Horiz +Step Resp, Rep Rate switch to 250 kHz, and adjust
the Amplitude control for a six-division display.
b. Set the 7B53A for a calibrated sweep rate of five
nanoseconds/division (use X10 magnifier) . Set the trigger
source switch internal adjust trigger level control and
position control for a stable display, centered on the
graticule.
c. CHECK-Check for optimum square corner and flat
top on displayed pulse with aberrations not to exceed +0 .1
or -0 .1 division with total peak-to-peak aberrations not to
exceed 0.1 division .
d . ADJUST-High-frequency compensation as given in
Table 3-2 for optimum square leading corner and flat top
with minimum aberrations within limits given in part c.
Location of adjustments is shown in Fig. 3-3. Use the
low-capacitance
screwdriver to adjust the variable
capacitors . Repeat the complete adjustment procedure
several times to obtain optimum adjustment.
3- 1 0
TABLE 3-2
High-Frequency Compensation
e. Remove the calibration fixture from the left vertical
compartment and install it in the right vertical compart-
ment .
f. Set the VERT MODE switch to RIGHT.
g. CHECK-Optimum square leading corner and flat top
on the displayed pulse with aberrations not to exceed +0.1
or -0 .1 division, with total peak-to-peak aberrations not to
exceed 0.1 division .
h. ADJUST-If necessary, compromise the adjustment
of C420, R421, R425, C425, C427, R427 for best response
from both the left and right vertical compartments .
i . To verify
correct high-frequency compensation,
perform the bandwidth check as given in next step.
16. Check Vertical Amplifier Bandwidth
a. Connect the high-frequency constant-amplitude signal
generator to the CW In connector of the mainframe
standardizer calibration fixture.
b. Set the Test switch of the calibration fixture to Vert
or Horiz Freq Resp .
c. Set the 7B53A for a sweep rate of 0.2 microsecond/
division .
d. Set the high-frequency generator for six divisions of
deflection, centered on the graticule, at a reference fre-
quency of 3 megahertz.
e. Without changing the output amplitude, increase the
output frequency of the high-frequency generator until the
display is reduced to 4.2 divisions (-3 dB point) .
REV . B, OCT . 1977
Primary Area
Adjustment
Of Pulse Affected Best Sweep Rate
C420 and First 50 nano- 50 nanoseconds/
R421 seconds division
R425 and First 20 nano-
20 nanoseconds/
C425 seconds
division
C427 and
First 5 nano- 20 nanoseconds/
R427
seconds divisions