Pioneer tuning fork Service Manual page 21

@. Luminance Level Control
Luminance level of color bars is variable within the range
of ± 2 0 %
©. Setup
Setup level or black level of all patterns is variable within
the range of 0—10%. Adjusting method is shown on* the
Table 1. Connection and setting of an oscilloscope are as
follows:
Connect the generator t o the vertical input of a triggered
oscilloscope which has a bandwidth more than 10MHz.
Test Items
Video level
(Setup)
©. Video Output
This terminal puts out a composite video signal and ac­
cepts A 75 O BNC plug.
O u t p u t voltage Fixed: A p p r o x . lVp-p (75 Q load)
Variable: 0—1.5Vp-p (75 D load)
Polarity Positive (negative sync signals)
The output is a composite signal of pattern, synchroniz­
ing, blanking and burst signals. This has positive polarity
with negative sync pulses to conform to the polarity of vid­
eo equipment.
©. Level Control
Video output level is variable within the range of 0 —
1.5Vp-p with a 75 O load. When this control is set at
P R E S E T , the output is l V p - p (75 O load). This control
does not affect R F modulation.
Set the oscilloscope's input-mode to D C and sensitivity to
LOMV.
When the black level is raised, the percentage of luminance
amplitude is raised. Table 3 shows the levels of bars when
the black level is adjusted at 7 . 5 % with the setup level
control.
Test Point Panel Control and Value
of adjustment
VIDEO OUT Set the pattern selector
(Front) to Color and video level
control to Preset.
Obtain a desired setup
value.
Adjust chrominance and
luminance level so as to
produce a video output
of 1 Vp-p.
Table 1 Video Level Setup
©. Scanning
Selects I N T E R L A C E D O R P R O G R E S S I V E scanning
Interlaced scanning: The trace lines of a field appear be­
tween the lines of the previous field as in the normal TV
broadcasting picture. This is used for viewing color bars
and rasters.
Progressive scanning: The trace lines of a field appears on
the same lines of the previous field making the picture
coarse but flickerless. This is better for viewing Crosshatch,
dots and center cross patters.
©. Raster
Switch for selecting R E D , G R E E N , BLUE or W H I T E .
(On LCG-399 eight colors are selectable by combining
R E D , G R E E N and B L U E raster buttons.)
Place of Measuring
Adjustment Instruments
SETUP Oscilloscope
or Vec-
CHROMA torscope
LUMINANCE
(Front)
Selector
Selector
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