Daewoo DTQ-26S1FC Service Manual page 7

GENERAL ADJUSTMENTS
1. GENERAL
In the majority of cases, all color televisions will need only
slight touch-up adjustment upon installation. Check the basic
characteristics such as height, focus and sub- basic
characteristics such as height, focus and sub- bright. Observe
the picture for good black and white details without
objectionable color shading.
2. VERTICAL HEIGHT ADJUSTMENT
1) Tune in an active channel.
2) Adjust brightness and contrast controls for a good picture.
3) Adjust vertical height control (R305) for approximately one
half inch over scan at top and bottom of picture screen.
4) Vertical centering adjustment R310
Horizontal centering adjustment R516.
3. FOCUS ADJUSTMENT
1) Tune in an active channel.
2) Adjust brightness, sharpness and contrast controls for a
good picture.
3) Adjust focus control (part of T402) for sharp scanning lines
and/or sharp picture.
4. RF AGC ADJUSTMENT
1) Tune in an active channel.
2) Using the attenuator, apply the signal of 60dBm to the
antenna input terminal.
3) Turn RF AGC control (R113) full clockwise until snow
or/and noise appears in the picture, then slowly turn control
counter clockwise until snow or/and noise disappears.
5. HIGH VOLTAGE CHECK
High voltage is not adjustable but must be checked to verify
that the receiver is operating within safe and efficient design
limitations as specified:
1) Operate Receiver for at least 15 minutes at 120V AC line.
2) Set brightness sharpness, contrast and color control to
minumum position (Zero beam).
3) Connect accurate high voltage meter to CRT anode. The
reading should be 26kv~28kv
If a correct reading cannot be obtained, check circuity for
malfunctioning components.
6. X-RADIATION PROTECTION CIRCUIT TEST
When service has been performed on the horizontal
deflection system, high voltage system or B+system, the X-
RADIATION protection circuit must be tested for proper
operation as follows:
1) Operate receiver for at least 15 minutes at 120V AC line.
2) Adjust all customer controls for normal picture and sound.
3) Short R414(X-RAY Short test), and remove short clip.
4) If the operation of horizontal osc. does not stop in step
The circuit must be repaired, before the set is returned to
the customer.
7. CRT GRAY SCALE ADJUSTMENT
1) Tune in an active channel.
2) Set the COLOR control to minimum.
3) Turn the SCREEN control (on T402 fully counter-
clockwise.)
4) Rotate the RED, GREEN and BLUE BIAS controls (R917,
R918, R919) counterclock wise from the maximum, set
them to the position where notches in the knobs become
parallel to the surface of P.C. Board.
5) Set the GREEN and BLUE DRIVE controls (R920, R921)
to the mid position.
6) Turn the service switch SW901 (Service Position) on the
CRT board.
7) Rotate the SCREEN control (on T402) gradually
clockwise until the second horizontl line following the first
line appears slightly on the screen. Then turn fully
counterclockwise the two BIAS controls corresponding to
the colors of the first and the second horizontal lines to
eliminated the lines.
8) Set the SCREEN control to the position where the third
horizontal line lights slightly on the screen.
9) Adjust the two BIAS control set to the minimum in item 7)
above to obtain the slightly lighted horizontal line in the
same levels of three (red, green, blue) colors. (The line
should be white if the BIAS controls are adjusted
properly.)
10) Turn the service switch SW901 again (Normal position on
the CRT board.)
11) Press PICTURE-SEL, P-UP and set the brightness and
contrast controls to the maximum.
12) Adjust the BLUE and GREEN DRIVE control to obtain
proper white-blanced picture in high light areas.
13) Using P-SEL, P-DN key, set the brightness and contrast
controls to obtain dark gray raster. Then check the white
balance in low brightness. Of the white balance is not
proper, retouch the BIAS controls and DRIVE controls to
obtain a good white balance in both low and high light
areas.
8. MAIN B+(103V) ADJUSTMENT
1) Tune in an active channel
2) Check TP10 (DC 103V Line) using D.V.M
3) Adjust voltage control (R809) for main B+(DC 103V)
9. SUB-BRIGHTNESS ADJUSTMENT
1) Tune in a color program.
2) Set the CONTRAST control to maximum and the
BRIGHTNESS control to maximum and the
SHARPNESS control to the center position.
3) Set the COLOR and TINT controls to center.
4) Set the SUB-BRIGHT control R522 to center and
leave the receiver on five minutes in this state.
5) Watching the picture carefully, adjust the SUB-
BRIGHT control in the position where the picture does
not show evidence of blooming in high brightness area
and not appear too dark in low bright area.
6) Check for BRIGHTNESS controls at both extremes.
7) If the picture does not appear dark with the
CONTRAST and BRIGHTNESS control turned to
minimum, or not appear bright with the controls turned to
maximum, adjust the SUB-BRIGHT control again for an
acceptable picture.
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