Checks and Adjustments
1720/1721
5–23
b. Connect the Function Generator red clip lead to pin 7 ( +Y) on the
rear-panel X Y INPUT connector. Connect the Function Generator black
clip lead to pins 1 (–X) and 5 (–Y).
c. Adjust R846 (Y Gain) for a Y axis display equal to the vertical distance
between the centers of the dB boxes.
d. Move the Function Generator red clip lead from pin 7 to pin 3 (+X) on
the rear-panel X Y INPUT.
e. Adjust R948 (X Gain) for a display amplitude equal to the horizontal
distance between the centers of the dB boxes.
f. Connect the Function Generator red clip lead to both pin 7 ( +Y) and pin
3 (+X) on the rear-panel X Y INPUT. Leave.the Function Generator
black clip lead connected to pins 1 (–X) and 5 (–Y).
g. Check that the ends of the trace are within the dB boxes.
10. Adjust XY Phasing
a. Leave the Function Generator connected as in part f. of the preceding
step.
b. Set the Function Generator frequency to 100 kHz.
c. Adjust C484 (VHF Comp) for minimum opening in the diagonal trace.
11. Adjust Loop DC Balance
a. Connect the black burst signal to CH-A INPUT. Do not terminate.
b. Switch INPUT to CH-A and MODE to VECT.
c. Use the 1720/1721 PHASE control to place color burst directly on the
burst axis. Color burst amplitude will be twice normal length because it
is unterminated.
d. With one end-line and two feed-through terminators, triple terminate the
open side of the CH-A INPUT loop-through. The color burst amplitude
should now be 50% of normal.
e. Adjust R534 (Loop Balance) to return the color burst vector to its axis.
f. Repeat steps c. through e. as necessary.
12. Adjust Quad Phase and +V Balance
a. Reconnect the color bar signal to both CH-A and CH-B INPUTs.
To Next Page
Loading...
Need help?
General
