Daewoo DTQ-14N2FC Service Manual page 10

GENERAL ADJUSTMENTS 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. If color shading is
evident, demagnetize the receiver. If color shading still
persists, perform purity and convergence adjustments.
This should be all that is necessary to achieve Optimum
receiver performance.
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 VR316
Horizontal centering adjustment VR556.
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 24kv~26kv
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
(R906, R913, R920) 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 (R911,
R918) 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 TP7 (DC 103V Line) using D.V.M
3) Adjust voltage control (R820) for main B+(DC 103V)
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