Noblex 21TC657, Service Manual

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Contents
-2-
Safety Notice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Chassis Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
IC Block Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
Service Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-16
Purity and Convergence Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Cabinet Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Chassis Electrical Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-26
Safety Notice
SAFETY PRECAUTIONS
1: An isolation transformer should be connected in the
power line between the receiver and the AC line
when a service is performed on the primary of the
converter transformer of the set.
2: Comply with all caution and safety-related notes pro-
vided on the cabinet back, inside the cabinet, on the
chassis or the picture tube.
3: When replacing a chassis in the cabinet, always be
certain that all the protective devices are installed
properly, such as, control knobs, adjustment covers
or shields, barriers, isolation resistor-capacitor net-
works etc.. Before returning any television to the
customer, the service technician must be sure that
it is completely safe to operate without danger of
electrical shock.
X-RADIATION PRECAUTION
The primary source of X-RADIATION in television receiver is the picture tube. The picture tube is specially con-
structed to limit X-RADIATION emissions. For continued X-RADIATION protection, the replacement tube must be
the same type as the original including suffix letter. Excessive high voltage may produce potentially hazardous X
- RADIATION. To avoid such hazards, the high voltage must be maintained within specified limit. Refer to this ser-
vice manual, high voltage adjustment for specific high voltage limit. If high voltage exceeds specified limits, take
necessary corrective action. Carefully follow the instructions for + B1 volt power supply adjustment, and high volt-
age check to maintain the high voltage within the specified limits.
PRODUCT SAFETY NOTICE
Product safety should be considered when a component replacement is made in any area of a receiver.
Components indicated by mark
in the parts list and the schematic diagram designate components in which
safety can be of special significance. It is particularly recommended that only parts designated on the parts list
in this manual be used for component replacement designated by mark
. No deviations from resistance
wattage or voltage ratings may be made for replacement items designated by mark .