Atec Tektronix-1502 - Manual (Page 52)

TM 9-4935-601-14-3&P
Adjustment Procedure
(b). Set CABLE DIELECTRIC to SOLID POLY. Locate two time marks on the graticule with the
DISTANCE dial.
(c). Check-for 7.75 to 8.1 divisions between time marks.
77. (a). Set CABLE DIELECTRIC to SOLID PTFE. Locate two time marks on the graticule with the
DISTANCE dial.
(b). Check-for 8.25 to 8.55 divisions between time marks.
78. (a). Set METRES/DIV to 50, set CABLE DIELECTRIC to OTHER, and turn CABLE DIELECTRIC VAR
fully clockwise.
(b). Turn the DISTANCE dial as necessary to see two markers and note the timing between the
markers.
(c). Turn CABLE DIELECTRIC VAR fully counterclockwise.
(d). Check-that the timing is reduced to 50%
±
2% (3.4 to 3.6 divisions) of the timing noted in part b.
(e). Return the CABLE DIELECTRIC VAR to fully clockwise position.
79. Turn off the 1502, remove all test equipment and reinstall U1575. Install the shield over the
pulser/sampler circuitry (install 12 screws). Return the instrument to normal viewing position.
80. Turn on the 1502 and set mp/DIV to 500, set the METRES/DIV to 5, set CABLE DIELECTRIC to
OTHER and adjust the DISTANCE dial to 000.
X.1 Positioning
81. Connect the precision 50
Ω
terminator to the CABLE connector.
82. Set the METRES/DIV multiplier to X1.
83. Set the incident pulse to a graticule reference line with the ZERO REF control, then set the
METRES/DIV multiplier to X.1.
84. Check-that the leading edge of the incident pulse is located within 2 divisions of the selected graticule
reference line.
85. Adjust-R1132 (X.1 POS CAL) located on the MAIN board, so that the leading edge of the incident pulse
is located on the selected graticule reference line. Repeat steps 82 through 84.
VERTICAL CHECKS AND ADJUSTMENTS
Pulse Strobe and Risetime
86. Set the mp/DIV control to 500. Connect the probe adapter to the CABLE connector if the connector is
the grounding type (grounded CABLE connector used SN B040616 and up).
87. Use the ZERO REF SET and POSITION controls to locate the pulse at the graticule center.
88. Check-that the incident and reflected pulse both have equal amplitudes (see Fig. 4-10 for photos of the
correct display).
89. (a). Adjust-R1525 (AVAL VOLT), R1538 (SNAP-OFF), and R1692 (TD BIAS) located on the MAIN
board, for a correctly triggered display as shown in Fig. 4-10.
(b). Disconnect the probe adapter.
Loop Gain
90. Set the FEET/DIV (METRES/DIV) to 20 (5), MULTIPLIER to X1, and mp/DIV to 200.
91. Connect the precision 50
Ω
terminator (Tektronix Part No. 011-0123-00) to the CABLE connector.
92. Use the ZERO REF SET control to locate the pulse on the graticule. Use the POSITION controls as
necessary to locate the entire pulse step on the graticule.
REV B FEB 1980
4-14