Tektronix 442 Service Manual page 91

Calibration Procedure—442 Service
Performance Check
Figure 4-4. Timing accuracy check test setup.
18. Magnified Sweep Accuracy
a. Set:
MAGNIFIER X10 (button in)
SEC/DIV Tu
SOURCE EXT
b. Set the time-mark generator for a .1 us marker
output.
c. CHECK-—For one marker per each graticule divi-
sion within 5% over the center eight graticule divisions.
Exciude the first division (50 ns) of magnified sweep and
all divisions beyond the 100th magnified division.
d. Disconnect the test setup.
19. TV Mode Check
NOTE
This step may be omitted if the 442 is not planned to
be used for displaying television sync signals. A
television receiver or any other convenient source of
television sync signals may be used as the signal
source for this check (see Table 4-1, item 7). This
step lists appropriate signal amplitudes for checking
both internal and external TV MODE Performance
Requirements. To check internal triggering
(SOURCE set to CH 1/CH 2 or COMP), set the
VOLTS/DIV and VOLTS/DIV VAR to attenuate the
TV signal to one division of composite sync or 2.3
divisions of composite video on the crt display.
REV A MAY 1980
If a television receiver is used as the signal source,
an isolation transformer must be installed between
the receiver and its power input source if the receiver
does not have atransformer operated power supply.
a. Set:
VERT MODE CH 1
VOLTS/DIV (CH 1) As required
VOLTS/DIV VAR (CH 1) As required
SEC/DIV 1m
TRIGGERING MODE TV
SOURCE CH 1/CH 2
MAGNIFIER X1 (out)
b. Attach a compensated 10X probe to the Channel 1
input connector. Connect the probe ground lead to the
circuit ground on the television signal source and connect
the probe tip to an appropriate composite sync or
composite video test point.
e. Set the SEC/DIV switch to 50 wu.
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