Single Sweep - Tektronix 1S1 Instruction Manual

g. Reset the following test oscilloscope controls:
Time/Cm
Millivolts/Cm
Input Atten
Vc Range
h. Check for a leading corner on the waveform similar
to that shown in Fig. 5-9B. Duration of the indicated por-
tion of the waveform should be about 0.4µsec (2cm).
i. Adjust R460 (CONTROL TD BIAS) if the display is not
as indicated. See Fig. 5-10 for the location of R460.
j. Switch the RECOVERY TIME control out of SYNC posi-
tion and set it to midrange.
k. Remove the probe from the test point.
STAIRCASE AND FAST RAMP ADJUSTMENTS
6. Adjust Staircase DC Level
a. Reset the following Type 1S1 controls:
DISPLAY MODE
TIME POSITION
FINE
SAMPLES/CM
TIME/CM
b. Reset the following test oscilloscope controls:
Vc Range
Millivolts/Cm
Input coupling
Time/Cm
c. Connect the test probe to the staircase output at the
cathode of D285 (see Fig. 5-11).
d. Free run the test oscilloscope trace and position it for a
zero-volt dc reference level.
e. Set the test oscilloscope Input Coupling switch to Dc.
Fig. 5-12. Typical test oscilloscope display for checking
adjustment of R270 (STAIRCASE DC LEVEL).
.2 µSec
20
1
+11

SINGLE SWEEP

Clockwise
Clockwise
MIN (Clockwise)
5µSEC
0
10
Gnd
0.2mSec
Fig. 5-13. Typical test oscilloscope display for checking
adjustment of R380 (INVERTER DC ZERO).
f. Trigger the test oscilloscope.
g. Check for a dc level of zero volts at the bottom of
the main portion of the waveform (see Fig. 5-12).
h. Adjust R270 (STAIRCASE DC LEVEL) if the display is
not correct. See Fig. 5-11 for the location of R270.
i. Disconnect the probe from the test point.
7. Adjust Inverter DC Zero
a. Set the test oscilloscope Input Coupling switch to Gnd.
b. Connect the test probe to the junction of R370 (DELAY
ZERO) and R372 (see Fig. 5-11).
c. Free run the test oscilloscope trace and reset the zero
dc reference level.
d. Set the Input Coupling switch to Dc.
e. Adjust R370 to position the free-running trace to the
horizontal centerline of the test oscilloscope. See Fig. 5-11
for the location of R370.
f. Move the test probe tip to the staircase inverter input,
located at the junction of R372 and R377 (see Fig. 5-11).
This is at the other end of the same resistor.
g. Trigger the test oscilloscope display.
h. Check for a dc level of zero volts at the top of the
displayed waveform (see Fig. 5-13).
i. Adjust R380 (INVERTER DC ZERO) if the level is not
correct. See Fig. 5-11 for the location of R380.
j. Disconnect the test probe. (if this step is performed
out of sequence, be sure to reset the DELAY ZERO adjust-
ment as given in step 11.)
Calibration – Type 1S1
5-13