76FW-53H (serv.man13). DA100 and DW100 training course notes - Sharp TV Service Manual (repair manual). Page 12

Colour Television – DA100/DW100 Chassis

Sharp Electronics (UK) Ltd

Technical Support

September 99

Page 9

The operation of the field output circuit is similar to the audio with the exception that there is no mute
circuit except for C511, which will stop the circuit from operating until the +13v supply, is present.

The PWM signal from pin 4 of the IC, is passed through a low pass filter (L352 and C504) producing a
ramp signal at the field deflection coils. This ramp waveform will vary between +13v when the scan is
at the top of the screen decreasing to –13v when the scan has reached the bottom of the screen. The
field scan coils are returned to ground via Q503. Q503 is turned on during the vertical scan period and
turn off during vertical fly-back.

IC502 will produce an error signal. This error signal is fed to the vertical drive input (IC501 pin 11), for
the purpose of linearity and amplitude correction.

-

+

PRE

-

+

PWM

16

14

7,13

12

6

4

5

15

17

1,2,3,18,19,20

9

10

8

11

N.C

Vcc pow

Vcc sign

Boot

Boot Diode

Vref

-Vcc

-Vcc

Freq

Sign-GND

St-By/Mute

Feedcap

TDA7480

Input

R544
1k

C524
330nF

C507
4n7

C503
100pf

R510
8k2

-13v

C506
100nF

C508
560pF

R511
150

C504
680nF

C505
100nF

+13v

R509
39k

L352

C534
1nF

Field Coils

R516
1k

R518
1R

R501
150

R533
1R

Q503

Vertical
Flyback

C511
2.2

Vertical
Flyback

R503
1k

R502
4k7

IC502

R512
4k7

R515
1k2

1

2

3

IC501

+5v