Atec Tektronix-1502 - Manual (Page 50)

TM 9-4935-601-14-3&P
Adjustment Procedure
58. Set the FEET/DIV multiplier to X1.
59. Set the incident pulse to a graticule reference line with the ZERO REF control, then set the FEET/DIV
multiplier to X.1.
60. Check-that the leading edge of the incident pulse is located within 1 division of the selected graticule
reference line.
61. 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 58 through 60.
HORIZONTAL CHECKS AND ADJUSTMENTS-OPTION 5, METRIC VERSION
(See Step 38 for Standard Version)
Horizontal Gain Presets
NOTE
If the unit is only being checked and not calibrated, or if the unit is to be used
with the optional chart recorder, do not perform the following Horizontal Gain
Presets procedure. Instead, turn to the metric version Timing procedure
beginning with step 67.
62. Set the mp/DIV to 500.
63. Use the POSITION controls to center the trace on the graticule.
64. Set R3217 (HORIZ) located on the OUTPUT AMPS board, to the counterclockwise stop.
65. Adjust-R3213 (H POS) located on the OUTPUT AMPS board, to center the trace on the graticule.
66. Adjust-R3217 (HORIZ) so that the retrace at the start of the sweep is just off the graticule area and the
trace covers all 10 divisions of the graticule.
NOTE
Once the horizontal gain has been set, do not change it.
Timing
67. Connect the Marker Out of the TG 501 through a coaxial cable and a 10X attenuator to the CABLE
connector of the 1502; also connect the TG 501 Trigger Out to the Trig/Duration Input of the PG 502.
Turn the instrument POWER off. Turn the instrument upside down and remove the shield that covers the
pulser/sampler circuitry (remove 12 screws). Remove U1575 from its socket. In the following steps,
instructions are given on how to provide an external trigger to the 1502 (see Fig. 4-6).
68. Set the 1502 controls as follows:
mp/DIV 200
METRES/DIV 25 @ X1
DIELECTRIC AIR (all buttons out)
DISTANCE 000
69. Set the controls of the PG 502 Pulse Generator as follows:
Duration 50
µ
s
Variable Duration Fully ccw
Period Ext Trig
Low Level -1.5
High Level 2.5
Back Term Pull Out
All pushbuttons Out
70. Set the TG 501 Time Mark Generator for 0.5 us time marks. Connect a coaxial cable from the TG 501
+ Trigger Out to PG 502 Trig/Duration Input. Connect a 1X probe from the PG 502 Output to the Red test point
located near U1575. Connect a coaxial cable and a 10X attenuator from the TG 501 Marker Out to the CABLE
connector. Turn the instrument POWER on.
NOTE
The time marks must not exceed 0.85 V to keep the tunnel diode in the low
state.
71. (a). Obtain the waveform on the 1502 crt as shown in Fig. 4-9. Use the variable pulse amplitude
control of the PG 502 and the DISTANCE control of the 1502 to align the time marks with the crt graticule lines.
NOTE
If the instrument is to be used with the optional chart recorder, continue with the
remainder of this step. If the instrument is not to be used with a chart recorder,
proceed with step 72, part a.
REV C FEB 1980
4-12