LG CH480 6B free download

File name CH480_6B.pdf

R,G,B R,G,B R,G,B SIGNAL Video Drive Video Output PC TUBE Circuit Circuit V-Sync. H-Sync. Screen 2nd Rectifier Circuit Mode Control Vertical Output Anode Transformer Circuit Circuit -9- V Primary Switching BLOCK DIAGRAM Rectifier Control Circuit Circuit H High Voltage Horizontal / Vertical Generation Circuit Drive Circuit E L N AC LINE VOLTAGE DISCRIPTIONS OF BLOCK DIAGRAM 1. PRIMARY RECTIFIER CIRCUIT This is a circuit that transform a AC (line voltage) of wall to DC voltage as the supplied source in chassis. It is operated by C904 (electrolytic capacitor) and D901 (bridge diode). 2. SWITCHING CONTROL CIRCUIT This block operate to be kept the outputs of the 2nd rectified circuit in constant level in any conditions. : no load, full load, line voltage variation, etc. The main function is operated by IC901 (STR5717) syncronizing to H-frequency via a connector that tie around the core of the FBT (T702). 3. 2nd RECTIFIER CIRCUIT This block rectifying the pulse waveform of the transformer generated by switching control circuit. It is consisted of capacitor and diode. The output voltages are 125V, 95V, 70V, 40V, 12V and 6.3V that are necessary to the chassiss operation. 4. VIDEO DRIVE CIRCUIT This block is pre-amplify the video signal (Red, Green and Blue) of PC to make sufficient signal of the video output circuit. The function is operated by IC301 (TDA4881/2). 5. VIDEO OUTPUT CIRCUIT This block amplify the pre-amplified signal through the video drive circuit to drive the CDT (Cathode Display Tube). The cascode amplify stages and buffer stages of each color are used to this block and the drive transistor of cascode amplifier lies inside of the IC301. The buffer stages are consist of PNP and NPN type of transistor. 6. MODE CONTROL CIRCUIT This block genera