Text preview for : sm-cb20h1t.pdf part of Samsung sm-cb20h1t Samsung TV sm-cb20h1t.pdf
Back to : sm-cb20h1t.pdf | Home
COLOR TELEVISION RECEIVER
Chassis : S15A
Model: CB20H1T5X
CB20H1Z5X
CB21H1T5X
CB21H1Z5X
COLOR TELEVISION RECEIVER CONTENTS
1. Precautions
2. Specifications and IC Data
3. Disassembly and Reassembly
4. Alignment and Adjustment
5. Troubleshooting
6. Exploded View and Parts List
7. Electric Parts List
8. Block Diagram
9. PCB Layout Diagram
10. Wiring Diagram
11. Schematic Diagrams
Precautions
1. Precautions
Follow these safety, servicing and ESD precautions to prevent damage and protect against potential
hazards such as electrical shock and X-rays.
1-1 Safety Precautions
1. Be sure that all of the built-in protective
devices are replaced. Restore any missing (READING SHOULD
NOT BE ABOVE
protective shields. DEVICE
LEAKAGE
CURRENT 0.5mA)
UNDER TESTER
TEST
2. When reinstalling the chassis and its TEST ALL
assemblies, be sure to restore all protective EXPOSED METAL
SURFACES
devices, including: nonmetallic control knobs
2-WIRE CORD
and compartment covers.
ALSO TEST WITH
PLUG REVERSED
3. Make sure that there are no cabinet openings (USING AC ADAPTER EARTH
PLUG AS REQUIRED) GROUND
through which people--particularly
children--might insert fingers and contact
dangerous voltages. Such openings include
Fig. 1-1 AC Leakage Test
the spacing between the picture tube and the
cabinet mask, excessively wide cabinet
6. Antenna Cold Check:
ventilation slots, and improperly fitted back
With the unit's AC plug disconnected from the
covers.
AC source, connect an electrical jumper across
the two AC prongs. Connect one lead of the
If the measured resistance is less than 1.0
ohmmeter to an AC prong. Connect the other
megohm or greater than 5.2 megohms, an
lead to the coaxial connector.
abnormality exists that must be corrected
before the unit is returned to the customer.
7. X-ray Limits:
The picture tube is especially designed to pro-
4. Leakage Current Hot Check (Figure 1-1):
hibit X-ray emissions. To ensure continued
Warning: Do not use an isolation
X-ray protection, replace the picture tube only
transformer during this test. Use a leakage-
with one that is the same type as the original.
current tester or a metering system that
Carefully reinstall the picture tube shields and
complies with American National Standards
mounting hardware; these also provide X-ray
Institute (ANIS C101.1, Leakage Current for
protection.
Appliances), and Underwriters Laboratories
(UL Publication UL1410, 59.7).
8. High Voltage Limits:
High voltage must be measured each time ser-
5. With the unit completely reassembled, plug
vicing is done on the B+, horizontal deflection
the AC line cord directly into the power
or high voltage circuits. Correct operation of
outlet. With the unit's AC switch first in the
the X-ray protection circuits must be
ON position and then OFF, measure the
reconfirmed whenever they are serviced.
current between a known earth ground (metal
(X-ray protection circuits also may be called
water pipe, conduit, etc.) and all exposed
"horizontal disable" or "hold-down".)
metal parts, including: antennas, handle
brackets, metal cabinets, screwheads and
Heed the high voltage limits. These include
control shafts. The current measured should
the X