Goodmans C520 Schematic

GOODMANS C520

X-RAY RADIATION PRECAUTION

1. Excessive high voltage can prcduce
potentially hazardous X-RAY RADIATION.
To avoid such hazards, the high voltage
must not be above the specified limit. The
nominal value of the high voltage of this
receiver is 19K volts at zero beam
current(minimum brightness) under
230VAC power sources. The high voltage
must not, under any circumstances, exceed

22.5K volt each times a receiver requires
servicing, the high voltage should be
checked following the HIGH VOLTAGE
CHECK procedure.
It is recommended the reajing of the high
voltage be recorded as a parts of the
service record. It is important to use an
accurate and reliable high voltage meter.

2. The only source of X-RAY RADIATION in
this TV receiver is the picture tube. For
continued X-RAY RADIATION protection,
the repiacernent tube must be exactly the
same type tube as specified in the parts
list.

SAFETY PRECAUTION

1. Potentials as high as 17,000 volts are
present when this receiver is operation.
Operation of the receiver outside the
cabinet of which the back board removed
involves a shock hazard from the receiver.

1) Servicing should not be attempted by
anyone who is not thoroughly familiar with
the precautions necessary when working
on high-voltage equipment.

2) Always discharage the picture tube anode
to the receiver chassis to keep off the
shock hazard before removing the anode
cap.

3) Perfectly diseharage the high potential of
the picture tube before handling the tube.
The picture tube is highly evacuated and if
brocken, glass fragments will be violently
expelled.

2. If any fuse in this TV receiver is blown,
replace it with the FUSE specified in
Replacement parts list.

3. When replacing a high wattage resistor
(oxide metal film resistor) in circuit board
keep the resistor 10mm away from circuit
board.

4. Keep wires away from high voltage or high
temperature components.

5. This receiver must operate under AC230
voltage, 50Hz never connect to any other
DC supply or power or frequency.

Adjustments
VIF DET. COIL ADJUSTMENT

1) The MEASUREMENT UNIT connect as

shown in Figure 3.

2) Set the VIP ADJUSTMENT MEASURE-

MENT UNIT from the left (FREQUENCY
(MHz) of Figure 4.)

Figure 3. The Method of the Measurement
Unit Connection (See opposite)

3) FREQUENCY(MHz) MARKER POINT adjust
the DETECTOR COIL (T103) to maximum.

Figure 4. The Wave Shape of VIP
TRAP COIL ADJUSTMENT

1) The measurement unit connect as shown in
figure 5.

2) Set the adjust measurement unit from the left
(Frequency MHz of Figure 6)

Fig 5. The method of the measurement unit
connection

3) Frequency (MHz) marker point aijust the trap

coil (T101) to maximum.

Fig 6. The wave shape of trap (See opposite)

SCREEN VOLUME ADJUSTMENT

1) Fix the video output DRIVER VOLUME VR604,
605 and the video output BIAS VOLUME
VR601, 602, 603 to the VOLUME center.

2) Adjust the BRIGHTNESS and the CONTRAST
VOLUME to minimum.

3) Change the SERVICE SWITCH SW203 to the
SERVICE position.

4) Becoming the CROSSWAY A LINE, adjust the
SCREEN VOLUME.

WHITE BALANCE ADJUSTMENT

1) Fix the SERVICE SWITCH to the SERVICE
position.

2) The CROSSWAY A LINE adjust the BIAS
VOLUME VR601, 602, 603 the white.

3) Fix the SERVICE SWITCH to the NORMAL
position.

4) Attach the LUMINANCE METER to the contrast
to maximum.

5) Adjust the BRIGHTNESS and the CONTRAST
to minimum.

6) The LED of the LUMINANCE METER adjust

the video output BIAS VOLUME to the green
color.

7) Adjust the brightness and the contrast to
minimum.

8) The LED of the luminance meter adjust the
video output bias volume to the green color.

9) Adjust again to a (5), (6), (7), (8) clauses.

FOCUS VOLUME ADJUSTMENT

1) Receive the LION PATTERN.

2) Adjust the brightness and the CONTRAST
VOLUME to maximum.

3) Adjust the focus volume to clearness.

ABL ADJUSTMENT (Automatic Brightness
Control Limit)

1) Receive the CROSS HATCH PATTERN.

2) Adjust the brightness and the CONTRAST
VOLUME to maximum.

3) Connect TPX, Y POINT with the DC VOLTME­TER.

4) The voltage of TPX, Y POINT adjust the SUB
BRIGHTNESS VOLUME (SVR201) to 230 ±
5(mV).

AGC ADJUSTMENT

1) Receive the UHF Channel 21.(Then, the input
level of the RF must to be 90dB-100dB)

2) The UHF Channel 21 adjust the AGC VR
(SVR101) to be disappear the Noise.

3) The input level 100dB check to be saturated by
the VHF channel reception.

V-SIZE ADJUSTMENT

1) Receive the LION PATTERN. (When the LION
PATTERN don’t exist, use to the PATTERN with
correspondence)

2) Adjust the V-SIZE (SVR301) to be identified
with the OVER SCAN 10% of the horizonztal

3) Adjust the VERTICAL POSITION VR (SVR302)
to be identified with the CENTER POSITION of
the VERTICAL CENTER.

H-CENTER ADJUSTMENT

1) Receive the LION PATTERN.(When the LION
PATTERN doesn’t exist, use the PATTERN with
correspondence)

2) Adjust the H-CENTER VR (SVR105) to be
indentified with the center position of the
horizontal center.

HIGH VOLTAGE CHECK
CAUTION: There is no HIGH VOLTAGE ADJUST-

MENT on this chassis. The +11(±20) DC volt
power supply must be properly adjusted to insure
the correct high voltage.

1) Connect an accurate high voltage meter to
anode of the picture tube.

2) Turn on the receiver. Set the BRIGHTNESS
and CONTRAST controls to minimum. (zero
beam current)

3) High voltage will be measured about 19KV.

4) Rotate the BRIGHTNESS control to the both
extremes to be sure the high voltage does not
exceed the limit of 22.5KV under any condi­tions.

COLOR PURITY ADJUSTMENT
NOTE: Before attempting any purity adjustments,

the receiver should be operate for at least 20
minutes.

1) Demagnetize the picture using a deguassing
coil.

2) Turn the CONTRAST and BRIGHTNESS
controls to maximum.

3) Adjust RED and BLUE BIAS control (VR601
and VR603) to provide only a green raster.
Advance the GREEN BIAS control (VR602) if
necessary.

4) Loosen the clamp screw holding the yoke, and
slide the yoke backward to provide vertical
green belt (zone) in the picture screen.

5) Rotate and spread the tabs of the 1 purity
magnet (See fig 7) around the neck of the
picture tube until the green belt is in the center

of the screen. At the same time, center the
raster vertically.

6) Move the yoke slowly forward until a uniform
green screen is obtained. Tighten the Clamp
screw of the yoke temporarily.

7) Check the purity of the red and blue raster by
adjusting the BIAS controls.

8) Obtained a white raster, referring to “CRT
GRAY SCALE ADJUSTMENT.”

9) Proceed with convergence adjustment.

Fig 7. Purity and Convergence Magnets
CONVERGENCE MAGNET ASSEMBLY POSI-

TIONING

Convergence magnet assembly need mechanical
positioning following the figures.

Fig 8. Tube Assembly
CONVERGENCE ADJUSTMENTS

Note: Before attempting any convergence

adjustments, the receiver should be operated for
at least fifteen minutes.

CENTER CONVERGENCE ADJUSTMENTS

1) Receive crosshatch pattern with a color bar
signal generator

2) Adjust the BRIGHTNESS and CONTRAST
controls for well defined pattern.

3) Adjust two tabs of the 4-Pole Magnets to
change the angle between them. And superim­pose red a blue vertical lines in the center area
of the picture screen.

4) Turn both tabs of the same time without
changing position between them to superim­pose red and blue horizontal lines at the center
of the screen.

5) Adjust the tabs of 6-Pole Magnets to superim­pose red/blue line with green one. Adjusting the
angle affects the vertical lines and rotating both
manets affects the horiaontal lines.

6) Repeat adjustments 3, 4, 5 observing
red,green and blue movement, because 4-Pole
Magnets and 6-Pole Magnets interact.

Fig 9. Center Convergence Adjustment

CIRCUMFERENCE CONVERGENCE
ADJUSTMENT

1) Loosen the clamp screw of deflection yoke
to allow the yoke to tilt.

2) Tilt front of the deflection yoke up or down
to obtain better convergence in circumfer­ence. Push the mounted wedge into the
space between picture tube and the yoke to
hold the yoke temporarily.

3) Place other wedge at bottom and remove
the cover paper to stick.

4) Tilt front of the yoke right or left to obtain
better convergence in circumference.

5) Keep the yoke positioned and put another
wedge in either upper space. Remove cover
paper and stick the wedge on picture tube to
secure the yoke.

6) Detach the temporarily mounted wedge and
put it in another upper space. Stick it on
picture tube to secure the yoke.

7) After inserting three wedges, recheck overall
convergence. Tighten the screw firmly to
hold the yoke tightly in place.

8) Place 3 adhesive tapes over, wedges as
shown in Fig 10.

9) Place a wedge temporarily. (Tempoarty
Mounting). (do not remove cover paper on
adhesive part of a new wedge).

Fig 10. Circumference Convergence
Adjustment

CRT GRAY SCALE ADJUSTMENT

1) Set the COLOR Control to minimum.

2) Adjust the BRIGHTNESS and CONTRAST
Control to obtain low light area

3) Adjust RED,GREEN and BLUE BIAS
Controls (601, 602, 603) to obtain gray
raster of low brightness.

4) Adjust the BRIGHTNESS and CONTRAST
Controls to maximum.

5) Adjust the BLUE DRIVE. (VR605) and RED
DRIVE Controls (VR604) to obtain proper
white balanced picture in high light areas.

6) Repeat step 2 through 5 for correct gray

scale.