Figure 4-10 – Atec Tektronix-1502 User Manual
Page 53
TM 9-4935-601-14-3&P
Adjustment Procedure
Figure 4-10. Pulse Display.
93. Adjust-the front-panel GAIN screwdriver control for a pulse amplitude of 5 divisions. (Adjust the
POSITION controls as necessary.)
94. (a). Set the FEET/DIV (METRES/DIV) to 200 (50).
(b). Check-that the rise of the pulse occurs within 0.1 division horizontally and there is a spike of ap-
95. (a). Adjust-R1543 (LOOP GAIN) located on the MAIN board so that the pulse is as described in the
previous step. See Fig. 4-11 for photos of correct and incorrect displays.
(b). Set the FEET/DIV (METRES/DIV) to 1 (.25), set the MULTIPLIER to.1, and set the CABLE DI
ELECTRIC to OTHER (VAR-fully cw). Use the ZERO REF and POSITION controls as necessary to locate the
pulse at graticule center.
(c). Remove the 50
Ω
terminator from the CABLE connector. Install the GR to bnc adapter and the GR
short. Check that the reflected risetime of the pulse (fall time) is 0.7 division ( 0.875 division). See Fig. 4-12.
Noise
96. Set the mp/DIV to 5, turn the ZERO REF fully counterclockwise and adjust the POSITION controls so
the top of the trace is located on the horizontal centerline.
97. Check-that the peak-to-peak noise is not greater than 10 mp (2 divisions).
98. Push the NOISE FILTER button in and check that the peak-to-peak noise is less than 4 mp (0.8
division).
99. Change the FEET/DIV (METRES/DIV) control to 20 (5). Turn ZERO REF fully clockwise.
100. Use the POSITION controls to set the bottom of the pulse at the horizontal centerline.
101. Check-that the peak-to-peak noise is less than 4 mp.
102. Release the NOISE FILTER button and check that the peak-to-peak noise is less than 10 mp.
103. Adjust--R1657 (LF COMP) located on the MAIN board, for the lowest possible peak-to-peak noise, then
repeat steps 96 through 102 above.
DC Balance
104. Set the mp/DIV to 100.
105. Connect the precision cable from the CABLE connector, to the female adapter, to the 50
Ω
terminator.
Use the POSITION controls to locate the base of the pulse at the horizontal centerline.
REV C FEB 1980
4-15