6-8. Vertical Deflection Circuit
The power amplifier driving the vertical yoke assembly is a DC design-based on power
amplifier I330 TDA8172.
The vertical deflection coil is connected to pin5 of I330 via P440. The saw- tooth signal is
derived from pin3 of I401 and fed to pin1 of I330 via R330 / C330.
The DC bias voltage is derived from pin21 of I401 and fed to pin7 of I330 via divider
R348 / R347 to optimize the vertical position. R335 /C336 is a fierce to stabilize the power
amplifier output.
There are two kinds of supply voltage for I330, -9V is applied to pin4 via R334,
+14V DC voltage is applied at pin2 and pin6 via D344 for the output stage during the retrace time.
The supply voltage for the output stage during the retrace time is derived from the fly-back
generator output on pin3 of I330 and applied through C343 to pin6 of I330.
6-9. Horizontal Deflection Circuit
The product is designed around a base-drive circuit for driving horizontal deflection circuit to
provide sufficient switching current.
Q429 is switched by the horizontal drive signal from pin26 of I401 via level- shift component
R424, C427 and D428; and connected pin1 of T430. It combined with DC14 V from Pin2 boosts a
sufficient output voltage on pin3 of T430. The snubber network R429/C429 compensates for
leakage inductance in T430 and shapes the base-drive waveform.
The drive signal is fed to base of Q433 via divider R431/R432. When Q433 is at the “ off “ state,
the voltage, which is stored on the base of Q433, discharge via D431. The drive signal controls
Q433 switch on and off, so that saw-tooth waveform current through the horizontal deflection coil
is obtained.
The positive horizontal fly-back pulse signal derived from pin6 of T440 is through R405 / R524
then fed to pin12 of I401. This fly-back signal not only provides proper timing reference for
horizontal drive output but also supplies necessary horizontal blanking coupled with vertical
blanking applied to the G1 circuit for video output.
The horizontal deflection output circuit uses the transistor switching function and combines
with a damping diode and makes saw-tooth wave current flow through a deflection coil.
The basic deflection circuit comprises switching transistor Q433; transformer T440; damper diode D434;
Co C434; Cm C435; Cs C405/ C472/C477 /C482 and linear coil L483.
The frequency table is for CS function as shown below.
