Read Sharp 76FW-53H (serv.man13) Service Manual online
Colour Television – DA100/DW100 Chassis
Sharp Electronics (UK) Ltd
Technical Support
September 99
Page 14
SCAN VELOCITY MODULATOR
The purpose of this circuit is to maintain the luminance level as the electron spot moves across the
CRT face.
CRT face.
The distance that the electron beam travels from the electron gun to the CRT face at the outer edges
of the CRT is greater than the distance from the electron gun to the centre of the CRT face. This
distance is emphasised more on 16:9 CRT’s than 4:3 CRT’s with deflection angles of 110°
of the CRT is greater than the distance from the electron gun to the centre of the CRT face. This
distance is emphasised more on 16:9 CRT’s than 4:3 CRT’s with deflection angles of 110°
This result in the intensity of the electron spot varying as it travels across the CRT face. To overcome
this a coil is placed around the CRT neck, close to the gun assembly. The purpose of this coil is to
increase/decrease the speed, the spot travels across the CRT face, therefore, maintaining luminance
transitions.
this a coil is placed around the CRT neck, close to the gun assembly. The purpose of this coil is to
increase/decrease the speed, the spot travels across the CRT face, therefore, maintaining luminance
transitions.
The signal that is used to control this circuit is derived from IC801 pin 34 and the amount of correction
can be adjusted by the end user via the picture menu.
can be adjusted by the end user via the picture menu.
Q5410
R5431
390
390
R5433
100
100
Q5411
Q5412
R5432
33
33
R5434
1k
1k
R5435
220
220
Q5406
Q5405
R5412
47
47
R5413
10
10
C5408
68nF
68nF
R5414
10
10
C5409
68nF
68nF
R5410
0
0
R5415
82
82
R5416
3k3
3k3
R5418
3k3
3k3
R5419
82
82
R5411
0
0
R5421
3R3
3R3
Q5408
Q5407
R5423
3R3
3R3
R5417
0
0
+5v
140v
+12v
R5425
470
470
IC801
pin 34
pin 34
SVM Coils
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