Tektronix 442, Instruction Manual

Page: 65 / 170

Calibration Procedure—442 Service
Adjustment Procedure
g. Connect a 10X probe to the CH 2 input connector.
Connect the probe tip to a probe-tip-to-bnc adapter, the
adapter to a 50 Q bnc termination, and the termination to a
50 O bnc 10X attenuator attached to the high-amplitude
output connector of the square-wave generator. Set the
generator to provide a 5-division, 1 kHz display.
h. Compensate the probe for the best front corner on
the displayed waveform.
e. ADJUST—R4397, C4397, C4396, R4396 (see Figure
4-9) and C114, R114 (see Figure 4-8), using a low-
capacitance alignment tool, for best front corner of the
waveform.
NOTE
For serial numbers B010409 through B022163, per­
form parts g, h, and i and ignore parts f and j.
i. Set CH 2 VOLTS/DIV to 20 m (IX) and set the
generator for a 5-division display.
For serial numbers below B010409 and above
B022163 perform parts f, g, h, andj and ignore part i.
j. ADJUST—C4213 for the best flat top on the square
wave.
k. Set CH 2 VOLTS/DIV to .2 (IX), and set the
generator amplitude to provide a 5-division display.
I. ADJUST—C4204 for the best flat top on the dis­
played square wave.
m. Disconnect the test equipment from the 442.
f. ADJUST—(For serial numbers below B010409 and
above B022163) C4155 (see Figure 4-9) for best front
corner of the waveform (use a low-capacitance alignment
tool).
g. Set VERT MODE to CH 2.
h. Move the 50 Q termination for the square-wave
signal from the Channel 1 input connector to the Channel
2 input connector.
6. High Frequency Compensation
a. Set:
VOLTS/DIV (CH 1 & CH 2)
VERT MODE
SEC/DIV
INTENSITY
LEVEL 2 m (IX)
CH 1
.5 m
For a visible display
For a triggered display
b. Connect the square-wave generator fast-rise +
transition output through a 50 D cable, a 10X attenuator,
and a 50 Q termination to the Channel 1 input connector.
c. Set the generator for a 100 kHz, 5-division display
(set INTENSITY and POSITION controls for a visible
centered display).
d. Set SEC/DIV to .5 p, MAGNIFIER to X10 (button in)
and adjust LEVEL and INTENSITY for a visible, stable,
triggered, positive-going square-wave display. Set
Horizontal POSITION control to view the leading edge of
the square wave near the center of the graticule area.
i. ADJUST—(For serial numbers B010409 through
B022163) C4255 (see Figure 4-9) for best front corner of
the waveform (use a low-capacitance alignment tool).
j. CHECK—(For serial numbers below B010409 and
above B022163) for asquarefront corneronthe Channel 2
waveform similar to the Channel 1 waveform obtained in
part e.
k. INTERACTION—If either the Channel 2 waveform
or the Channel 1 waveform is not satisfactory, repeat the
adjustments and checks listed in parts e through i (as
appropriate for the serial number of the instrument being
adjusted) for best compromise of the waveforms for
Channel 1 and Channel 2. For example, slightly readjust
C4396, R4396, C4397, R4397, Cl 14, and R114 along with
C4255 (if present) for best Channel 2 display; then change
signal and Mode to Channel 1 and check the display.
Then, if necessary, readjust all listed components
(including C4155, if present). Repeat as required to
achieve best display front corner for both Channel 1 and
Channel 2.
I. Disconnect the test equipment from the 442.
4-22
R E V A M A Y 1980