Iiyama Vision Master Pro 451, Руководство по обслуживанию

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4-3. CONTROL circuits
(1) HORIZONTAL / VERTICAL OSCILLATION circuit
The H/V-sync signal input to IC350 is phase-sifted and converted to the waveform in IC350. The pulse
synchronized with the horizontal sync signal is output from pin 17 as horizontal drive pulse. The sawtooth wave
synchronized with the vertical sync signal is output from pin 4.
The pulse output from pin 17 generates a frequency locked to the input signal under the following conditions:
Q
The horizontal sync signal is input to pin 26.
R
The vertical sync signal is input to pin 27.
S
The feedback pulse (AFC pulse) of the HORIZONTAL DEFLECTION OUTPUT circuit is input to pin 18.
IC350 (UPC1888FCT) is auto-sync system and adjusts the horizontal frequency automatically make the vertical
sync signal input to pin 27 trigger. In case that the AFC pulse is not input, the output pulse from pin 17 is
unlocked and the horizontal picture size changes with keeping it small and picture is not synchronized.
(2) VERTICAL DEFLECTION circuit
The sawtooth wave output from pin 4 of IC350 is amplified by IC401 (V-OUT-IC) and then supplied to the
deflection yoke as a vertical deflection current to control the vertical deflection.
V-position is controlled by changing the DC component of the sawtooth wave output from pin 4.
IC350 pin 26 H-sync input
(2V/div)
IC350 pin 17 HD-OUT output
(10V/div)
IC350 pin 18 AFC input
(5V/div)
<Horizontal Waveform>
IC350 pin 27 V-sync input
(5V/div)
IC350 pin 4 sawtooth-wave
output (2V/div)
IC401 pin 2 V-OUT output
(20V/div)
<Vertical Waveform>