Adjustment Procedure-2445A/2455A Service
e.
Repeat steps b through d
as
necessary to minimize
trace shift until no further improvement
is
noted.
f.
Disconnect the setup.
2.
Check/Adjust Readout Jitter (R805 and R618).
NOTE
If
the previous step was not performed, first set up
the Initial Control Settings before the Dynamic
Centering adjustments, then proceed as follows.
a.
Rotate the
~
REF
OR
DL
Y
POS
control
CCW
until
the RATIO readout
is
constant.
b.
Rotate the
~
control until the readout display indi-
cates 130.0%.
c.
CHECK-One
cursor
is
near the bottom horizontal
graticule
line
and
the other
is
near the dotted graticule line
marked 100(%).
d.
Rotate the
~
REF
OR
DL
Y
POS
control until the
readout displays exactly 100.0%.
The
cursors should now
be
on
or
near the dotted graticule lines marked
0%
and
100(%).
e.
Set the
CH
1 VOL TS/DIV VAR to the detent
position.
NOTE
Care must be taken
not
to disturb the position
of
the
controls adjusted in parts b through e during the bal-
ance
of
this procedure.
If
they are accidentally
moved, repeat the procedure from the beginning.
f.
Set the A SEC/DIV to 1
ms
(knobs locked).
g.
Select
CH
1 for display.
h.
Press
and
release the
~
V button
to
obtain a
~
V
display, if necessary.
5-22
i.
Connect a 1-kHz, fast-rise signal from the Calibration
Generator to the
CH
1
OR
X input connector
via
a 50-fl
BNC
cable.
j. Set the generator output
level
for
an
8-division
display.
k.
Use the
CH
1 Vertical
and
the Horizontal POSITION
controls to center the
CH
1 display on the graticule.
I.
ADJUST-Vertical Readout Jitter (R618) for minimum
vertical jitter
of
the readout characters
and
cursors.
m.
ADJUST
-Gain
(R638)
and
Centering (R639) to
align cursors with the
O
and
100% graticule markings.
n.
Disconnect the 1-kHz signal.
o.
Press the
~t
button to obtain a
~t
cursor display.
p.
Using the
~
REF
OR
DL Y
POS
and
~
controls, posi-
tion the cursors to the 2nd and 10th graticule lines.
q.
Press the
X10
MAG
button to magnify the display.
r.
ADJUST
-Horizontal
Readout Jitter (R805) for
minimum horizontal jitter
of
the readout characters and
cursors.
3.
Set
CH
1 and
CH
2
DC
Balance.
NOTE
The
instrument must have had a 20-minute warmup
prior to performing the
next
step to ensure accuracy.
a.
Set
CH
1
and
CH
2 Input Coupling to 1 Mil
AC.
b.
Press
and
hold momentarily
and
then release the
CH
1
and
CH
2 upper Input Coupling switches
simultaneously.
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