Tektronix 7B51 Instruction Manual page 60

Performance Check/Calibration-Type 71351
g. CHECK-For proper triggering with the LEVEL/
SLOPE control at 0/+ and 0/-. Check for no trace with the
LEVEL/SLOPE control near the top and near the bottom .
h. Reset the Type 71351 TIME/DIV to 50 us and
MAGNIFIER to X1 . Set the Type 191 to 50 kHz and
adjust the amplitude for a four division display . Adjust the
Type 71351 LEVEL/SLOPE for a stable display. Reset the
TRIGGERING MODE to SINGLE SWEEP.
i . CHECK-Remove the signal from the Type 7A16 .
Press the Type 71351 RESET button and check that the
READY lamp is lighted . While observing the display, recon-
nect the signal to the Type 7A16 and check for one
displayed sweep (it may be necessary to increase the
INTENSITY to observe the display) . Check that the
READY lamp is out at the end of the sweep.
j. Reset the Type 71351 TRIGGERING MODE to P-P
AUTO and SOURCE to EXT. Adjust the Type 191 for a
1 .5 division (750 mV) display .
k. CHECK-Rotate the LEVEL/SLOPE throughout its
range and check for stable triggering at all positions.
I . Change the "T" connector from the Type 191 to the
low-frequency sine-wave generator output connector.
m. Set the Type 71351 TRIGGERING COUPLING to
DC and SOURCE to INT. Set the Time/Div to 10 ms .
n . Set the low-frequency sine-wave generator to 50 Hz
and adjust the amplitude for a 2 division display.
p. Remove the 50 Hz signal from the Type 7A16 and
Type 71351 .
9. Check/Adjust Sweep Calibration (SWP CAL, a
front-panel adjustment)
a. Reset the Type 71351 TIME/DIV to 1 ms and
COUPLING to AC .
b. Apply 1 ms markers from the Type 184 time-mark
generator to the Type 7A16 Input.
5- 8
o. CHECK-A stable display can be obtained .
Fig . 5-2 . Typical CRT display showing correct sweep calibration .
c. CHECK-CRT display for one 1 ms marker for each
division between the second and tenth vertical lines (see
Fig. 5-2) .
NOTE
Unless otherwise noted, use the center eight hori-
zontal divisions when checking or adjusting timing.
d.
ADJUST-SWP CAL, a front-panel adjustment, for
one marker for each division . The second and tenth markers
must line up exactly with their respective graticule lines
(use the horizontal POSITION control as necessary to line
up the display) .
e. CHECK-Timing accuracy is within 5% over any two
division interval within the center eight divisions .
f. INTERACTION : Check 10, 11, 13, 14, 15, 16 and
17 .
10 . Check/Adjust Magnified Sweep Gain (13785)
a. Set the time-mark generator for .1 ms markers.
b. Set the Type 71351 MAGNIFIER to X10.
c. CHECK-CRT display for one .1 ms marker for each
division between the second and tenth vertical lines.
d. ADJUST-13785, Magnifier Gain, for one marker for
each division (use the horizontal POSITION control as
necessary to line up the display) .