DESCRIPTION OF BLOCK DIAGRAM
1. Line Filter & Associated Circuit.6. Horizontal and Vertical Oscillation.
This is used for suppressing noise of power input lineThis circuit generates the horizontal pulse and the vertical
flowing into the monitor and/or some noise generated inpulse by taking the H and V sync signal.
this monitor flowing out through the power input line.This circuit consists of the TDA4856(IC701) and the
That is to say, this circuit prevents interference betweenassociated circuit.
the monitor and other electric appliances.
7. D/D(DC to DC) Converter.
2. Degauss Circuit & Coil.This circuit supplies DC voltage to the horizontal deflection
The degauss circuit consists of the degaussing coil, theoutput circuit by increasing DC 50V which is the
PTC(Positive Temperature Coefficient) thermistor(TH901),secondary voltage of the SMPS in accordance with the
and the relay(RL901). This circuit eliminates abnormalinput horizontal sync signal.
color of the screen automatically by degaussing the
shadow mask in the CRT during turning on the power8. Side-Pincushion & Trapezoid Correction Cirucit.
switch. When you need to degauss in using the monitor,This circuit improves the side-pincushion and the
select DEGAUSS on the OSD menu.trapezoid distortion of the screen by mixing parabola and
saw-tooth wave to output of the horizontal deflection D/D
3. SMPS(Switching Mode Power Supply).+
converter which is used for the supply voltage(B) of the
This circuit is working of 180~264V AC(50/60Hz).
deflection circuit.
The operation procedure is as follows:
1) AC input voltage is rectified and smoothed by the
9. Horizontal Deflection Output Circuit.
bridge diodes (D903) and the capacitor (C908).
This circuit makes the horizontal deflection by supplying
2) The rectified voltage(DC) is applied to the primary
the saw-tooth current to the horizontal deflection yoke.
coil of the transformer(T901).
3) The control IC(IC911) generates switching pulse to
10. High Voltage Output & FBT(Flyback Transformer).
turn on and off the primary coil of the transformer
The high voltage output circuit is used for generating pulse
(T901) repeatedly.
4) Depending on turn ratio of the transformer, the to the primary coil of the FBT(Flyback Transformer
secondary voltages appear at the secondary coils of(T701)). A boosted voltage(about 25.5kV) appears at the
the transformer(T901).secondary of the FBT and it is supplied to the anode,
5) These secondary voltages are rectified by each focus, and screen voltage of the CRT.
diode(D941, D951, D961, D971) and operate other
circuit. (horizontal and vertical deflection, video
11. H-Linearity Correction Circuit.
amplifier, ...etc.)
This circuit corrects the horizontal linearity for each
horizontal sync frequency.
4. X-ray Protection.
If the high voltage of the FBT reaches up to 29kV (abnormal
state), Q807 operates and IC401(MICOM) pin 41 come to12. Vertical Output Circuit.
low level. Then MICOM control IC701 (Deflection controller)This circuit takes the vertical ramp wave from the
to stop Horizontal drive pulse and stop Horizontal Deflection. TDA4856(IC701) and performs the vertical deflection by
supplying the saw-tooth current to the vertical deflection
5. Micom(Microprocessor) Circuit.yoke.
The operating procedure of Micom(Microprocessor) and its
associated circuit is as follows:
13. Dynamic Focus Output Circuit.
1) H and V sync signal is supplied from the signal cable.
This circuit takes the horizontal and the vertical parabola
2) The Micom(IC401) distinguishes polarity and
waves from the TDA4856(IC701) and amplifies it to
frequency of H and V sync.
maintain constant focus on center and corners in the
3) The Micom sets operating mode and offers the
screen.
controlled data. (H-size, H-position, V-size, ... etc.)
4) The controlled data of each mode is stored in itself.
5) User can adjust screen condition by each OSD
function. The data of the adjusted condition is stored
in EEPROM(IC402).
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ACEC
