Tektronix 1502 Service Manual page 63

FEET/DIV 100
(METRES/DIV) (25)
Multiplier x1
DISTANCE 000
DIELECTRIC Switches out
Set the time-mark generator for 5ps.
Select a time-mark and adjust the OUT-
PUT (VOLTS) (Low Level} control on the
pulse generator to place the mark on the
first graticule line in from the far right
Set the DISTANCE dial to 808 (metric to
202) while following and noting the posi-
tion of the time-mark from step 3.
After 808 (metric 202) is reached, adjust
R1315 (DIST.CAL) on the Main board to
move the time-mark to the first graticule
line in from the far left edge.
With the time-mark on the first graticule
line in from the left, depress the ZERO
REF CHECK pushbutton and check that
the time-mark returns to the first graticule
line in from the right.
Check the DISTANCE dial as per Table
4-5.
NOTE: The numbers in Table 4-5 are the
correct reading +2% + .5ft/5m. During active
use in the field, the DISTANCE readings will
be affected by any error or drift in the horizon-
tal timebase.
REV DEC 1988
Calibration - 1502
DISTANCE Dial Check
Graticule Line Standard Metric
From Left Edge
1 784 - 816 196 - 204
2 686 - 714 171.5- 178.5
3 588 - 612 147 - 153
4 490-510) 122.5-127.5
5 392 - 408 98 - 102
6 294 - 306 73.5 - 76.5
7 196 - 204 49-51
8 98 - 102 24-26
Turn off the 1502 and disconnect all test
equipment. Reinstall Ui575 on the Main
Board. Reinstall the sampler shield.
Turn on the 1502. Set mp/DIV control to
200 (500 metric), FEET/DIV control to 4
(2.5 metric) and turn DISTANCE dial to
X.1 Positioning
Attach a 50 © coaxial cable to CABLE
connector. Set Multiplier to X1.
Adjust ZERO REF (SET) control to posi-
tion leading edge of test pulse on vertical
reference line. Set Multiplier to X.1.
Leading edge of test pulse should be
within one division of vertical reference
line. If not within spec, adjust R1132
(X.1 POS CAL) on Main Board so that
leading edge of test pulse is within one
division of vertical reference line.
NOTE: This adjustment drifts with tem-
perature. Make sure the instrument is
fully warmed up before setting A1132.
4-17