4. Check Channel 2 Delay.
a.
Set:
VERTICAL
CH
1
and
CH
2 MODE
On
CH
3
and
CH
4 MODE Off
20 MHz BW LIMIT Off
CH
1
and
CH
2
Input Coupling 50
n
DC
CH
1
and
CH
2
VOL TS/DIV 10 mV
HORIZONTAL
A SEC/DIV
TRIGGER
SOURCE
1
µs
(knob
in)
CH
1
b.
Connect a 100 kHz, fast-rise, positive-going signal
from the Calibration Generator to the
CH
1
OR
X
and
the
CH
2 input connectors
via
a 50 n BNC cable, a
5X
attenuator
and
a Dual-Input Coupler.
c.
Set the output level of the Calibration Generator for
an
approximate 5-division, vertically-centered display for
both channels.
d.
Use
either the
CH
1 or
CH
2 VAR control to match
signal amplitude between both channels.
e.
Set:
A SEC/DIV
X10 MAG
10 ns (knob
in)
On
f.
Use
the Horizontal POSITION control
to
move the ris-
ing edges of the
CH
1
and
CH
2 displays
to
graticule
center.
g.
Pull
the SEC/DIV knob out
to
activate the
CH
2
DL
Y
feature.
NOTE
If
the readout displays "CH 2 DL Y DISABLED"
instead
of
"CH
2 DL
Y-
TURN
..:1.
the
delay matching
feature has been disabled and the remainder
of
this
subsection cannot be performed.
In
this
case,
proceed to subsection 5 below.
Performance Check-2445A/2455A Service
h.
CHECK-~
control will position the
CH
2 display 0.5
division
or
more (500
ps)
to either side of the
CH
1 display.
i.
Superimpose the rising edges of the pulses using the
~
control.
j. Turn
X10 MAG off
and
push
in
the SEC/DIV knob.
k.
Disconnect the test setup.
5.
Check Vertical
Bandwidth-All
Channels.
a.
Set:
HORIZONTAL
A SEC/DIV
TRIGGER
SOURCE
50
µs
(knob
in)
VERT
NOTE
Select channels to
set
VOL
TS/DIV.
VOLTS/DIV
CH
1
and
CH
2
CH
3
and
CH
4
VAR
CH
1
and
CH
2
VERTICAL MODE
20mV
0.1
V
Calibrated
(in
detent)
CH
1
On
CH
2,
CH
3,
and
CH
4 Off
Input Coupling
CH
1
and
CH
2 50 0
DC
b.
Connect the output
of
the Primary Leveled Sine-
Wave Generator
to
the
CH
1
OR
X input connector
via
a
precision 50 n
BNC
cable and any combination of the 1
OX,
5X,
or
2X
Attenuators needed to reduce the signal ampli-
tude
to
the level called out
in
the next step.
4-11
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