Skyworth 1418, 1422, 2122, 1498, 2522 Service Manual

SKYWORTH

®

SERVICE MANUAL

COLOUR TELEVISION PAL/SECAM BG/DK /NTSC
PLAYBACK

CHASSIS : 3N10, 4N10
MODEL : 1418, 1498, 1422, 2122,

2199, 21F1, L21, D21

CHASSIS : 5N10

MODEL:2522, 2588,25F1,2998,

2922
2929,29F1,3423, 3498,

3898,
L25, D25, L29, D29, L34,
D34

3N/ 5N10 7-2-2001

PDF created with pdfFactory trial version www.pdffactory.com

CONTENTS

PAGE

X-Ray RADIATION PRECAUTION

2

SAFETY PRECAUTION

2

PRODUCT SAFETY NOTICE

2

CHASSIS

3

COMPLETE MACHINE GENERAL

3-5

NOTES………………………………………………………………………………………………

5-9

COLOUR PURITY AND CONVERGENCE ADJUSTMENT

10

BLOCK DIAGRAM

11

WIRE DIAGRAM

12

SCHEMATIC
SPECIFICATIONS………………………………………………………………….………………

1

PDF created with pdfFactory trial version www.pdffactory.com

CAUTION

Before serving the chassis, read the "X-Ray Radiation Precaution", "Safety Precaution"
and "Product Safety Notice" on page 2 of this manual.

X-RAY RADIATION PRECAUTION

1. Excessive high voltage can produce potentially hazardous X-Ray Radiation. To avoid such
hazards, the high voltage must not be above the specified limit. The normal value of the high
voltage of this receiver is 24KV at zero beam current (minimum brightness) under 220V AC
power source. The high voltage must not, under any circumstances, exceed 29KV.

2. Each time a receiver requires servicing, the high voltage should be checked following the
High Voltage Check procedure in this manual. It is recommended the reading of the high
voltage be recorded as a part of the service record. It is important to use an accurate and
reliable high voltage meter.

3. The primary source of X-Ray Radiation in this TV Receiver is the picture tube. For continued
X-Ray Radiation protection, the replacement tube must be exactly the same type tube as
specified in the part list.

4. Some parts in this receiver have special safety – related characteristics for X-Ray Radiation
protection. For continued safety, parts replacement should be undertaken only after referring
to the Product Safety Notice.

SAFETY PRECAUTION

Warning: Service should not be attempted by anyone unfamiliar with necessary precaution on
this receiver. The following are the necessary precautions observed before servicing this
chassis.

1. Since the power supply circuit of this receiver is directly connected to the AC power line, an
isolation transformer should be used during any dynamic service to avoid possible shock
hazard.

2. Always discharge the picture tube anode to the CRT conductive coating before handling the
picture tube. The picture tube is highly evacuated and if broken, glass fragment will be
violently expelled. Use shatter proof goggles and keep picture tube away from the
unprotected body while handling.

3. When replacing a chassis in the cabinet, always be certain that all the protective devices are
put back in place, such as: non-metallic control knobs, insulating covers, shields, isolation
resistor-capacitor network etc.

4. When replacing parts or circuit boards, disconnect the power cord.

5. When replacing a high wattage resistor (Metal oxide film resistor) on circuit board, keep the
resistor 10mm (1/2in.) away from circuit board.

6. Connection wires must be kept away from components with high voltage or high temperature.

7. If any fuse in this TV receiver is blown, replace it with the FUSE specified in the chassis part
list.

8. The receiver is designed to operate with 220V(50/60Hz) AC mains.

PRODUCT SAFETY NOTICE

Many electrical and mechanical parts in this chassis have special safety-related characteristics.
These characteristics are often passed unnoticed by a visual inspection and the X-Ray
Radiation protection afforded by them cannot necessarily be obtained by using replacement
components rated for high wattage, etc. Replaced parts which have these special safety
characteristics are identified in this manual and its supplements, electrical components having
such features are shaded on the schematic diagram and the part list.

Before replacing any of these components, read the part list in this manual carefully. The use of
substitute replacement parts, which do not have the same safety characteristics, as specified in
the part list may create shock, fire, and X-Ray Radiation or other hazards.

2

CHASSIS ADJUSTMENT

1. B+ voltage adjustment (For 3N and 4N chassis only)
1-1 Connect 220V AC 50Hz to CN601 and switch on power switch SW601;
1-2 Test the voltage with digital voltage meter between two terminals of C625;

PDF created with pdfFactory trial version www.pdffactory.com