Acer AF705, Service Manual

Page: 15 / 88

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5. DEFLECTION
A. SYNC RPOCESSOR:
H-sync & V-sync input to U1(up), then up output the H-out, V-out signal to U401 TDA4856.
The H-out, V-out always are positive.
B. HORIZONTAL PROCESSOR
Fig 3 is the block diagram of IC TDA4856.
The IC TDA4856 output vertical sawtooth and H-Drive signal to produce, H.V deflection.
Meanwhile TDA4856 output. BDRV signal (IC pin 6) that can control B
+
voltage.
C. VERTICAL OUTPUT
Fig 4 is the block diagram of IC TDA8172.
Input vertical sawtooth signal from TDA4856 to TDA8172, then TDA8172 produce vertical
deflection current.
D. HORIZONTAL OUTPUT STAGE
F<33K 33K<F<36K 36K<F<41K 41K<F<52K 52K<F<58K 58K<F<65K 65K<F
SW1 L L L H H H H
SW2 L H H L L H H
SW3 L L H L H L H
E. FLYBLACK TRANSFORMER
In the primary of F.B.T, there is about 1000Vpp in the LC resonant interval, It convert to the
secondary of F.B.T to produce about 25.3KV for CRT anode voltage.