Preamplifier Calibration - Tektronix A6902B Service Manual

Adjustment Procedure
- A6902B
Service
2.
Preamplifier Calibration
Equipment Required
(see Table
Oscilloscope
Calibration
Generator
3.
Gain Adjustment
Equipment
Required
(see Table
)
Oscilloscope
Calibration Generator
Power Module Power Module
Termination
Termination
Alignment
tool
(003-0675-00)
Probe (P6129)
Probe Adapter (013-0107-00)
a.
Set the instrument controls as
follows:
Alignment
tool
(003-0310—00)
Alignment
tool
(003-0675—00)
Probe
(P6129)
Probe Adapter
(013-0107-00)
Calibration
Generator
Mode
Period
Oscilloscope
Voits/Div
Position
Vertical
Mode
Time/Div
Trigger
Mode
A6902B
Isolator
Fast
Rise
1
ms
(1
kHz)
100
mV
Midrange
Channel
1
200 MS
Auto
Volts/Div (both)
100
mV
AC/COMMON/DC
(both)
AC
b.
Using
the oscilloscope
probe and
the retractable
hoot-tip adapter,
connect
the oscilloscope
to
J2122
(J2622)
with
the
probe ground
lead
at-
tached
to
J2231
(J2633).
c.
Install
the
50
Q
termination on
the positive-going,
fast-rise
output
of
the calibration generator.
Using
the probe-tip-to-BNC
adapter,
connect the
A6902B
probe
to
the termination.
NOTE
When
adjusting 20-turn variable
resistors,
lightly
tap
them
to
center
the
backlash.
Set the Instrument controls
as
follows:
Calibration
Generator
Mode
Standard Amplitude
Amplitude
0.5
V
Period
1
ms
(1
kHz)
Oscilloscope
Voits/Div
100
mV
Position
Midrange
Vertical
Mode
Channel
1
Time/Div
200 MS
Trigger
Mode
Auto
A6902B
Isolator
Volts/Div (both)
100
mV
AC/COMMON/DC
(both)
AC
d.
Set
the oscilloscope
friggering controls
for
a
stable display
and
center the display
on
the
screen.
e.
Adjust
C4040
for
the squarest
waveform
front
corner.
(Disregard
AC
line
noise
if
present.
Using
the
BW
LIMIT on the oscilloscope
may
be help-
ful.)
f.
Adjust R1041
to
Its
center-point,
b.
Connect
the
A6902B
output
to the oscilloscope
vertical input.
c.
Using
the probe-tip-to-BNC adapter,
connect
the
A6902B
probe
to
the standard amplitude output
of
the
calibration generator.
d.
Set the oscilloscope friggering controls
for
a
stable display
and
center the display
on
the
screen.