TB 9-6625-2183-24
b. Adjustments
(1) Adjust R1310 GEOM (fig. 1) for trace parallel with center horizontal graticule line
(R).
(2) Connect oscilloscope calibrator SOURCE/MEASURE CHAN 1 to TI CH1 X
INPUT, using 50 feed-through termination.
(3) Set CH1 VOLTS/DIV switch to 20 m.
(4) Set oscilloscope calibrator for a 50 kHz level sine output and adjust amplitude
for an 8 division display on TI.
(5) Adjust R208 (fig. 1) for maximum amplitude display (R).
(6) Disconnect cable from CH1 X INPUT and connect multimeter to P280 and P260 (fig. 2).
(7) Adjust CH1 vertical POSITION control for 0 V on multimeter.
(8) Move the low lead of the multimeter to chassis ground and adjust R265 (fig. 2)
for 38.0 V dc (R).
Figure 2. Top left - equipment setup.
9. Step Attenuator Balance
a. Performance Check
(1) Set VOLTS/DIV switches to 20m and adjust CAL controls fully cw to detent.
(2) Set AC-GND-DC switches to GND.
(3) Adjust CH1 POSITION control to move trace to center horizontal graticule line.
(4) Set CH1 VOLTS/DIV switch to 50m. If trace does not remain on horizontal
graticule centerline within 1.5 divisions, perform b (1) below.
(5) Set display mode switch to CH2 and press trigger source CH2 pushbutton.
