v.
On
2455A instruments,
ADJUST--HF.
Adjust (R417)
if necessary to meet the criteria given
in
steps t
and
u.
w.
Press
and
release the upper TRIGGER COUPLING
switch.
x.
Check-Readout
indicates
ADJ
~
(step)
2,
10
mV,
10
ns.
y.
Connect the high amplitude generator, Tunnel Diode
Pulser,
5X
attenuator combination to
CH
1
OR
X input via
a
50-0 BNC cable.
z.
ADJUST-Trans
Resp
adjustments (R410, C403,
and
the
~
control) for best response.
aa.
Disconnect the Tunnel
Diode
pulser
and
connect
the fast rise output of the Calibration Generator to
CH
1
OR
X via a
5X
attenuator
and
a 50-0 BNC cable. Note the
amount of roll up or roll down
in
the first 3
ns.
This
difference represents the error between the Tunnel Diode
pulser
and
the fast rise generator.
bb.
Press
and
release the upper TRIGGER COUPLING
switch (step
3).
Move the test signal to
CH
2
and
ADJUST
-amplitude
for 5-division signal.
cc.
ADJUST-~
until
CH
2 waveform matches that
noted
in
step
aa
abOve.
dd.
Press
and
release the upper TRIGGER COUPLING
switch (step
4).
Connect the test signal to
CH
1 through
2X,
2.5X,
and
5X
attenuators. ADJUST
~
for best front
corner.
ee.
Press
and
release the upper TRIGGER COUPLING
switch (step
5).
Remove 2.5X attenuator. ADJUST
~.
for
best corner.
ff.
Press
and
release the upper TRIGGER COUPLING
switch (step
6).
Remove
5X
attenuator. ADJUST genera-
tor for a 5-division signal. ADJUST
~
for
same
corner
noted
in
step
ee
abOve.
Adjustment Procedure-2445A/2455A Service
gg. Press
and
release the upper TRIGGER COUPLING
switch (step
7).
Adjust generator for 5-division signal.
ADJUST
~
for best corner.
hh.
Press
and
release the upper
TRIGGER
COUPLING
switch (step
8).
Adjust generator for a 5-division signal.
ADJUST
~
for best corner.
NOTE
Generator amplitude for the 500-mV step will
be
approximately 2 divisions and the amplitude for
the
1-V step will be approximately 1 division.
ii.
Remove
2X
attenuator. Continue through step
11
as
abOve.
jj. Press
and
release the upper TRIGGER COUPLING
switch. Steps
12
and
13
are
automatically calibrated. Con-
nect test signal to
CH
2 via 2X, 2.5X,
and
5X
attenuators
and adjust for 5-division signal.
ADJUST~
for best corner.
kk. Repeat steps dd through
ii
for
CH
2 (steps 14-21).
II.
Steps 22
and
23 are automatically calibrated after
step
21.
mm.
CHECK-Readout indicates VERT
CENTER
GAIN.
nn.
ADJUST
-Gain
(R638) for precisely 5 divisions
between the two horizontal cursors.
oo.
ADJUST
-Vertical
Centering (R639) to center the
cursors
on
the graticule (align the cursors with the dotted
0%
and
100(%) graticule
lines).
pp.
Press
and
release the upper TRIGGER COUPLING
switch.
qq. Disconnect the test setup.
5-19
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