TB 9-6625-2134-24
Figure 16. Log and Video Amplifier - Adjustment Locations.
(203) Press 2 dB/DIV VERTICAL DISPLAY pushbutton to on. Adjust variable
attenuator for 10 dB attenuation output. If crt does not indicate 5 divisions of vertical
deflection (down) adjust R4020 (fig. 16) slightly in the same direction, then remove 10 dB
from variable attenuator and adjust Level R4071 (fig. 16) for a full crt display. Repeat this
check until 10 dB step is within 0.2 dB.
(204) Press 2 dB/DIV VERTICAL DISPLAY pushbutton to on and disconnect
signal generator from J621 (fig. 16).
(205) Position display on crt to bottom graticule line, using horizontal
POSITION control.
(206) Reconnect signal generator output to J621 (fig. 16). Adjust Level R4081
(fig. 16) for a full-screen display on crt (8 divisions).
(207) Press 10 dB/DIV VERTICAL DISPLAY pushbutton to on and set variable
attenuator switches for 40 dB.
(208) Adjust R1085 (fig. 16) to position display to midscreen.
(209) If a large change in adjustment R1085 (fig. 16) was required, repeat technique
of (203) through (206) above.
NOTE
Log amplifier adjustments interact.
(210) Press 10 dB/DIV VERTICAL DISPLAY pushbutton to on and switch
variable attenuator through 10 dB steps. If display on crt does not indicate one division
0.25 minor division for each 10 dB step, repeat technique of (193) through (209) above.
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