Tektronix 516 series, Instruction Manual

Page: 46 / 132

14. SWP. LENGTH R176.
With 1-millisecond markers ap­
plied to the Vertical Amplifier, adjust the SWP. LENGTH ad­
justment for a sweep length of 10.5 divisions.
15. S W P ./M A G . REGIS. R358. Set the HORIZ. DISPLAY
switch to the MAG. position and adjust the HORIZONTAL
POSITION control to align the first marker with the vertical
centerline of the graticule. Then set the HORIZ. DISPLAY
switch to the NORM, position and adjust the SWP./MAG.
REGIS, adjustment to again align the first marker with the
center of the graticule. Repeat this step until the marker
remains horizontally centered as the HORIZ. DISPLAY switch
is changed from MAG. to NORM. Set the HORIZ. DISPLAY
switch to the NORM, position.
16. Check Sweep Timing— 2 seconds/div. to .1 milli-
second/div.
This step checks the accuracy of the sweep
timing components for sweep rates between 2 seconds per
division and .1 millisecond per division. There are no ad­
justments to be made. Table 6-1 lists the time markers to
be applied for the indicated settings of the TIME/DIV. switch
and the number of markers per division to be observed for
each setting. When checking sweep rates between .1 SEC
and 2 SEC, it will be necessary to adjust the STABILITY con­
trol for a stable display.
TABLE 6-1
TIME/DIV. TIME MARKERS
OBSERVE
.1 mSEC 100 /isec
1 marker/div.
1 mSEC 1 msec 1 marker/div.
2 mSEC 1 msec 2 marker/div.
5 mSEC 5 msec 1 marker/div.
10 mSEC 10 msec
1 marker/div.
.1 SEC 100 msec 1 marker/div.
1 SEC 1 sec 1 marker/div.
2 SEC
1 sec
2 marker/div.
17. 1-, 2 -, and 5-^.sec/div. Sweep Rates.
Capacitor
C160C determines the sweep rate for the 1-, 2-, and 5-^.sec
positions of the TIME/DIV. control.
Set the oscilloscope controls as outlined at the beginning
of the Time-Base Generator and Horizontal Amplifier section
with the exception of the TIME/DIV. control and the HORIZ.
DISPLAY switch. Set these controls to 5/xSEC and MAG.,
respectively. The STABILITY control may have to be adjusted
to obtain a stable display in the following timing adjustments.
Connect the time-mark generator to the A VERTICAL input
connector and display 1-microsecond markers. With the
HORIZONTAL POSITION control, position the display to the
left so that the last ten timing markers are visible. Adjust
C160C so that each time marker is directly coincident with a
vertical graticule line. It will be necessary to adjust the
HORIZONTAL POSITION control, as C160C is adjusted, to
align the time markers with the graticule lines.
18. 1-, 2 -, and 5-ju.sec/div. Linearity. Capacitor C330 com­
pensates a voltage divider network at the input circuit of the
Horizontal Amplifier, and affects the sweep rate of the early
part of the display at the faster sweep rates.
Calibration — Type 516
With the controls unchanged from Step 17, position the
display to the right until the first ten timing markers are
visible. Adjust C330 to align each time marker with a verti­
cal graticule line. Again, it will be necessary to adjust the
HORIZONTAL POSITION control, as C330 is adjusted, to
align the time markers with the graticule lines.
There is some interaction between C160C and C330. It
may be necessary to go back and forth two or three times
between steps 17 and 18 to obtain satisfactory calibration.
19. 10-, 2 0 -, and 50-^.sec/div. Sweep Rates.
Capacitor
C160E determines the sweep rate for the 10-, 20-, and 50-
/isec positions of the TIME/DIV. switch. To make this ad­
justment, set the HORIZ. DISPLAY switch to NORM, and the
TIME/DIV. switch to 10 ^.SEC. Display 10-microsecond mar­
kers from the time-mark generator.
Adjust C160E to obtain one time marker for each graticule
line.
2 0 . 2-^ sec/d iv. Linearity. Capacitor C224 is one of three
adjustments that determine the high-frequency response of
the horizontal amplifier, and thereby the linearity of the crt
display at the faster sweep rates. (The other two adjustments
are C260 and C384). The time constants of these circuits are
such as to permit adjustments at different sweep rates. C224
affects the response when the HORIZ. DISPLAY switch is in
the NORM, position only, and is initially adjusted to provide
the best linearity in the 2-/usec/div. range.
To make this adjustment, turn the TIME/DIV. control to 2
,u.SEC and display 1-microsecond markers from the time-mark
generator. Adjust C224 so that two markers per division are
displayed on the left half of the screen. You may ignore
the linearity on the right half at this point.
21. .2 - and .5-^.sec/div. Sweep Rate.
Capacitor C160A
determines the sweep rate for the .2 and .5 ^.SEC positions
of the TIME/DIV. control.
Continue displaying 1-microsecond markers, and turn the
TIME/DIV. control to .5 ^SEC. Make sure the VARIABLE
TIME/DIV. control remains in the CALIBRATED position. Ad­
just C160A so that a time marker is aligned with every other
graticule line.
22. .2-^.sec/div. Linearity. At the ,2-^.sec/div. sweep rate
the linearity of the crt display can be altered slightly by
adjusting C260. In addition, the linearity adjustments for
lower sweep rates become timing adjustments at the higher
sweep rates. This is particularly true of C224 (step 20), which
has a pronounced effect on the ,2-/isec/div. sweep rate. To
adjust C260 (which may require a readjustment of C224), set
the oscilloscope controls as follows:
TRIGGER SELECTOR HF SYNC
(red)
TRIGGER SELECTOR + INT.
(black)
HORIZ. DISPLAY
NORM.
TIME/DIV.
.2 juSEC
VARIABLE TIME/DIV. CALIBRATED
Set the time-mark generator for a 50 nanosecond sinewave
output, and adjust the STABILITY and A VERTICAL VOLTS/
6-7