Acer AC501 Manual

Also see for AC501: User manual

Contents

Acer AC501 Manual Manual pdf 18 page image

18I-4. Horizontal Driver CircuitThe driver pulse that come from U401 pin7 drive Q506,then transfomer T501 convert driver pulse to driver current todrive horizontal output transistor Q801.I-5. Horizontal Output StageThere is different Cs value in different horizontal frequency.Hf CsHf < 40K C805 + C804 + C814Hf < 58.5K C804 + C805Hf > 58.5K C804I-6. Flyback TransformerIn the primary of F, B, T, there is about 1103Vpp in the LC resonant interval, it convert to the secondary of F.B.T toproduce about 24.7KV for CRT anode voltage. The other bias for CRT is G4 (4~8KV), G2 (0~1000V) and G1 (-160V).J. Video AMP. CircuitJ-1. Video PRE. AMP.The video pre-amp IC is U301 (KA2143B). The input signal is 0.7Vpp, then pre-amp IC U301 amplify the video signalto 4~5Vp. The WHITE BALANCE and CONTRAST shall be adjusted by adjustment the bias voltage of U301. Fig. 5 isthe block diagram.J-2. Video AMPLIFIERThe video amplifier is U303 (LM2439), it amplify video signal to about 40Vpp. Video output signaladd to cathode by AC coupling. The DC bias is controlled by the output pwm of IC U302.J-1. Video PRE. AMP.The video pre-amp IC is U301(KA2143B). The input signal is 0.7Vpp, then pre-amp IC U301 amplify the video signalto 4~5Vpp. The WHITE BALANCE and CONTRAST shall be adjusted by adjustment the bias voltage of U301. Fig. 5is the block diagram.J-2. Video AMPLIFIERThe video amplifier is U303 (LM2439), it amplify video signal to about 40Vpp. Video output signal add to cathode byAC coupling. The DC bias is controlled by the output pwm of IC U302.