Service manual

program.

1.4.2.1 Corner purity circuit operation

<TL: Upper left corner>

Pin 50 (PWM_DAC) of IC102 controls the TL in the range of 0 to 5V while regarding 2.5V as the reference

voltage, and the DC current of the above value will flow from pin 2 of IC803 to the upper left corner purity

coil.

<TR: Upper right corner>

Pin 49 (PWM_DAC) of IC102 controls the TR in the range of 0 to 5V while regarding 2.5V as the reference

voltage, and the DC current of the above value will flow from pin 8 of IC803 to the upper right corner purity

coil.

<BL: Lower left corner>

Pin 52 (PWM_DAC) of IC102 controls the BL in the range of 0 to 5V while regarding 2.5V as the reference

voltage, and the DC current of the above value will flow from pin 2 of IC801 to the lower left corner purity

coil.

<BR: Lower right corner>

Pin 51 (PWM_DAC) of IC102 controls the BR in the range of 0 to 5V while regarding 2.5V as the

reference voltage, and the DC current of the above value will flow from pin 8 of IC801 to the lower right

corner purity coil.

1.4.3 Digital dynamic convergence clear (DDCC) circuit

In the digital dynamic convergence clear (hereafter called DDCC) circuit, the convergence compensating

current waveform is produced and amplified, and the convergence is compensated by the compensation

current flowing to the sub yoke that is installed as the rear unit of the deflection yoke.

Though the principle of the convergence compensation with the sub yoke is same as the CP ring, the CP

ring is used for the static variation with the parallel movement in the whole picture in the uniform magnetic

field with the permanent magnet but the sub yoke is used for dynamic variation that compensates a

desired position on the picture by controlling the current waveform that flows to the coil of the electric

magnet. (See Fig. 7)

1.4.3.1 Production of compensation current waveform

There are 30 kinds of compensation elements, and they are programmed in IC601 one by one using the

function. Inputting the compensation coefficient into the function controls the amplitude of the current.

Fig. 6 DDCC compensation image