TB 9-4931-538-40
i. Press More, Timebase, and TIME/DIV keys and set Sweep Speed = 200 ns/div.
j. If the trace is not horizontally flat l major division, perform k through n below. If
within tolerance, perform o below.
k. Preset the TB FINE TUNE (R54) on the horizontal assembly A1 (fig. 11) to
mechanical enter.
l. Adjust the FREQ ADJ TRIM CAP ON U9 on the horizontal assembly A1 (fig. 11)
until the trace is flat l major division (R).
m. Replace the tape over the FREQ ADJ TRIM CAP ON U9 (fig. 11). (Masking or
electrical tape can be used.)
n. Allow 10 minutes for U9 to stabilize its temperature, with the tape over the FREQ
o. Press Timebase key and set TIME/ DIV = 1.00 ms/div.
p. Adjust the R54 TB FINE TUNE (fig. 11) on the horizontal assembly A1 for the
flattest trace possible on display (R).
21. END and 4 ns CAL Adjustment
a. Set the display menu and mainframe settings to meet the following conditions:
(1) Press Display key. Display Mode to Average is highlighted. NUMBER OF
AVERAGES to # Averages = 4. Screen to Single is highlighted. Graticule to Grid is
highlighted. Bandwidth to 12A GHz is highlighted.
(2) Press Channels key. Channel 1 to display On is highlighted. Channel 2
through 4 display Off is highlighted. VOLTS/DIV to 20.00 mV/div for Channel 1
through 4. OFFSET to Offset = 0.000V. PROBE ATTEN to Chl Atten Factor = 1.000.
(3) Press Timebase key. TIME/DIV to Sweep Speed = 500 ps/div. DELAY to
Delay = 16.0000 ns. Delay Ref at Left is highlighted.
(4) Press Trigger key. TRIGGER LEVEL to Trigger Level = 0.000 V. Slope to
Pos is highlighted. PROBE/ATTEN to Ext Atten Factor = 1.000. HF Sens to Off is
highlighted. HF Reject to Off is highlighted.
d. Adjust the 4 NSEC CAL on horizontal assembly A1 (fig. 11) fully ccw.
e. Adjust the END on horizontal assembly A1 (fig. 11) for a small amount of trace
discontinuity at the beginning of the eighth vertical graticule division (fig. 13). If
necessary, adjust trigger level to center the trace discontinuity vertically on display.