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1.5
CRT compensation block
1.5.1
Rotation circuit
The rotation circuit is a circuit to compensate the picture inclination caused by the earth mag-
netism by letting DC current flow to the rotation coil wound on the front side of DY for adjust-
ment. It is controlled to 0 to 5V with the reference of 2.5V by IC103 pin 3 (PWM_DAC), and
DC current of +/-90mA (max) is made to flow to the rotation coil by IC804 pin 2.
This correction circuit has two functions; (1) User adjustment (OSD display) and (2) Southern/
Northern horizontal magnetic field rotation cancellation, as follows.
(1) User adjustment (OSD display)
User provides DC current to the rotation coil according to the value displayed on OSD.
(2) Southern/Northern horizontal magnetic field rotation cancellation
Southern/Northern horizontal magnetic field rotation cancellation is to automatically adjust
the variation of raster rotation by earth magnetism.
Detection voltage and direction of the southern/northern horizontal magnetic field (pin 2 of
IC214) is detected by IC214 (Earth magnetism sensor unit), and pin 18 of IC101
(CPU_ADC) reads the detected voltage and provides DC current to the rotation coil ac-
cording to the prescribed control program.
1.5.2
Corner purity circuit
The corner purity circuit is a circuit to compensate for the color shade and color deviation of
the picture corner. On the rear side of CRT, it is adjusted by DC current flowing to the corner
purity coils installed in the four corners on the display surface.
The compensation circuit is composed of the following four functions of (1) User adjustment
(OSD display), (2) Aging variation compensation, (3) High/low temperature drift compensation
and (4) Southern / Northern horizontal magnetic field landing cancellation.
(1) User adjustment (OSD display)
The user causes DC current of +/-60mA (max.) to flow to the purity coil of each corner
according to the value displayed on OSD.
(2) Aging variation compensation
As the electronic beam collides with the aperture grille, it is thermally expanded and con-
tracted. The thermal expansion/contraction is varied according to the elapse of the power
ON/OFF time of the monitor. The color shade and deviation of the picture corner thus
generated are automatically adjusted.
The voltage of the beam current supply pin (T701 pin 9) is detected with R723/R724, and
the voltage that detects the time elapse of the power ON/OFF of the monitor is read from
the CR charge (integration) circuit composed of C723 and R736 and CR discharge (inte-
gration) circuit, composed of C723 and R737 through IC702 (buffer amplifier) by IC101 pin
15 (CPU_ADC), and the DC current of +/-17mA(max) flows to the purity coil on each corner
according to the specified control program.
(3) High/low temperature drift compensation
The front panel (glass) is thermally expanded and contracted as the temperature varies in
the installation environments of the monitor. The color shade and deviation of the picture
corner are automatically adjusted. The voltage that detects the temperature variation of
the installation environments of the monitor is read from the environment temperature
detection circuit composed of TH101 (thermistor) arranged near the front panel (glass) by
IC101 pin 14 (CPU_ADC), and DC current of +/-13mA (max) is made to flow to the purity
coil on each corner according to the specified control program.
Summary of Contents for MultiSync FP1355 FP1355 FP1355
Page 23: ...1 17 Q502 Q502 Damper diode Current waveform fh 106k ...
Page 25: ...1 19 Q502 Q502 Damper diode Current waveform Q502 Ic Q502 Vce ...
Page 58: ...1 52 Figure 25 IC211 MC13289ASP block diagram ...
Page 63: ...1 57 Figure 30 IC212 XC3824P2 block diagram ...
Page 65: ...1 59 1 11 Wave form of main circuit voltage ...
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Page 120: ...MultiSync FP1355 User s Manual ...
Page 144: ... VSP C0464 REVISE 2 ...
Page 166: ...Fig 2 BEZEL LOGO VSP C0464 COLOR OF LETTERING Kingfisher Blue 6704 11 5 24 5 66 ...
Page 169: ...VSP C0464 Fig 5 1 PRINTING SPECIFICATION OF CARTON BOX North America ...
Page 170: ...VSP C0464 Fig 5 2 PRINTING SPECIFICATION OF CARTON BOX Europe ...
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