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1. Tune the television set or video recorder
receiver to a local channel.
A test tape or a signal generator also can be
used for service work.
2. Set the M O D E switch to C H 2 position.
3. Set the S W E E P T I M E / D I V switch to
lOjus/div position for observing T V horizontal
lines or to the 2 ms/div position for observing
TV vertical frames.
4. Set the S Y N C switch to T V position, and the
Slope switch to the " + " or " — "
(depending on the video signal).
5. Set the S O U R C E switch to INT position.
6. Best overall sync performance is obtained
when the T R I G L E V E L / P U L L A U T O control is
pushed in.
It may be pulled out initially to
provide comtinous sweep during set-up.
7. Set the CH2 D C - G N D - A C switch to the A C
position.
8. Connect a probe cable to the C H 2 input jack.
Connect the ground clip of the probe to the T V
set or video recorder chassis. With the probe
set for 1 0 : 1 attenuation, connect the tip of the
probe to the video detector output.
9. Set the C H 2 V O L T S / D I V switch for the largest
vertical
deflection
off-scale.
10. If necessary rotate the T R I G L E V E L control to
a position that provides a synchronized display.
1 1 . Adjust the S W E E P T I M E V A R I A B L E control
for two horizontal lines or two vertical frames
of composite video display.
12. If the sync and blanking pulses of the displayed
video signals are positive, set the
switch to the " + " position; if the sync and
H O R I Z O N T A L
C I R C U I T
P U L S E
D E F E C T
F R E Q U E N C Y
D I S T O R T I O N
N O R M A L
C I R C U I T
L O S S O F H I G H
F R E Q U E N C Y
R E S P O N S E
E X C E S S I V E
H I G H
F R E Q U E N C Y R E
S P O N S E .
N O N -
L I N E A R
P H A S E
S H I F T
L O S S O F L O W
F R E Q U E N C Y
R E S P O N S E
Fig. 2 1 A n a l y s i s of s y n c pulse distortion
20
position
possible without
going
S L O P E
E F F E C T
O N
O V E R A L L
R E C E I V E R
P I C T U R E
R E S P O N S E
P I C T U R E
N O R M A L
L O S S O F P I C -
T U R E
D E T A I L
F I N E
V E R T I C A L
B L A C K A N D
S T R I A T I O N S
L O W I N G A S H A R P
C H A N G E IN P I C
T U R E
S H A D I N G
C H A N G E IN S H A
D I N G O F L A R G E
P I C T U R E
A R E A S .
S M E A R E D P I C
T U R E
blanking pulses are negative, use the " — "
position.
13. Push in the T R I G L E V E L control and rotate to a
position that provides a well-synchronized dis-
play.
the
14. Adjust the P O W E R / I N T E N and F O C U S con-
trols for the desired brightness and best focus.
15. T o view a specific portion of the waveform,
such as the color burst, pull outward on the <>
POSITION
Rotate the same control left or right to select
the desired portion of the waveform to be
viewed.
16. Composite video waveforms may be checked
at other points on the video circuits by moving
the probe tip to those points and changing the
V O L T S / D I V control setting as required to keep
the display within the limits of the scale, and
by readjusting the T R I G L E V E L control
maintain stabilization.
Sync P u l s e Analysis:
The IF amplifier response of a television receiver
can be evaluated to some extent by careful obser-
vation of the horizontal sync pulse waveform. The
appearance of the sync pulse waveform is affected
by the IF amplifier bandpass characteristics. S o m e
typical waveform symptoms and their relation to IF
amplifier response are indicated in Fig. 2 1 . Sync
pulse waveform distortions produced by positive or
negative limitting in IF overload conditions are
shown in Fig. 22.
N O R M A L S Y N C
S Y N C P U L S E C O M P R E S S I O N
C A U S E D B Y
W H I T E
F O L -
" W H I T E " S A T U R A T I O N
C A U S E D B Y
Fig. 2 2 S y n c pulse w a v e f o r m s
control
for
X 5
magnification.
P U L S E
L I M I T I N G
L I M I T I N G
to
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