Service manual

STP 11-25R13-SM-TG
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Performance Steps
(6) If the CONTRAST control setting was changed as described in step g (2), return the
control to the preset position.
h. Adjust RGB SCREEN GAINS.
(1) On the VTSG, select a white flat field (100 IRE for NTSC or 100 percent for 50 Hz and 60
Hz PAL models).
(2) Set the VTSG white flat field within the range of the reference light-source.
(3) Check high light color balance (the color of the test spot matches the color of the light-
source reference field).
(4) Adjust the RGB GAINS until the color and brightness of the test spot match the light-
source reference field.
(5) For interaction, repeat steps h (2) through h (4) until properly matching the test spot and
obtaining the light-source reference field at both light levels.
i. Turn OFF the receiver/monitor and replace the back cover.
6. Operations check to ascertain that no problems exist.
a. Check that the power switch turns ON and OFF.
b. Check the operation of the volume control.
c. Set fine-tuning (for receivers).
(1) Turn to an active channel.
(2) Depress the automatic fine tuning (AFT) button to the OUT position.
(3) Rotate fine tuning CW until interference appears in the picture.
(4) Rotate fine tuning CCW until interference just disappears and color appears in the picture.
(5) Release the fine tuning ring.
(6) Set the fine-tuning for all active channels.
d. Check AFT (for receivers).
(1) Verify that fine-tuning is set.
(2) Press IN the AFT button.
(3) Check for correct picture, sound, and color lock on all active channels.
e. Adjust a color receiver/monitor using SMPTE color bars.
(1) Adjust BRIGHTNESS.
( a) Preset the CONTRAST control to mid-range.
( b) Adjust BRIGHTNESS while watching the black set, PLUGE, until the whiter-than-
black bars are no longer visible.
( c) Or instead of step (b) above, adjust BRIGHTNESS until the black bar above the black
set is completely black. Turn BRIGHTNESS until the black bar is reasonably gray;
then, turn it back down again just to the point at which the black bar ceases to get
any darker.
(2) Adjust CONTRAST until the white bar is quite gray; then turn it up just to the point at which
it just appears to change from gray to white.
NOTE: To avoid distortion, do not turn CONTRAST past the first blooming.
(3) Adjust HUE and CHROMA.
( a) Turn OFF the R and G SCREENS (or select BLUE ONLY, if available).
( b) Adjust HUE until the cyan and magenta bars are equal in intensity to the bars just
below them.
( c) Adjust CHROMA until the gray bar and blue bar are equal in intensity to the bars
below them.
( d) Turn ON all SCREENS or release the BLUE ONLY function.
7. Complete DA Form 2407 (Blocks 27, 28, and 36).
8. Turn the DA Form 2407 into the supervisor to inspect work.