Horizontal And Pincushion; Vertical Deflection Circuit - Sony KV-13FS100 Product & Training Manual

Horizontal and Pincushion

Note: Reference Figure 4-1 during circuit descriptions.
Horizontal Theory
The Horizontal Drive pulse (HD) is developed inside IC001 (OneChip) and output on IC001/pin 50. The HD is
first amplified by drive transistor Q502 and then applied to T505. T505 couples the signal to the Horizontal
output transistor Q505 or Q506 depending on model; Q506 is used in 20"; Q505 is used in 24". At this point, the
Horizontal output signal goes off in two directions. The signal is applied to the Fly-Back Transformer (FBT) and
is used to develop HV, G2, Heater, +200, Focus, ABL and +/- 13 voltages. It is also applied to the Horizontal
deflection yoke for horizontal scanning on the picture tube.
Pincushion Theory
Also shown on this diagram is the Pincushion correction circuit. The purpose of this circuit is to compensate for
the non-linear scanning characteristics of the horizontal deflection circuit. The distortion caused by this non-
linearity is the sides of the picture are bowed inward. The pincushion signal is used to incrementally increase the
drive current to the horizontal deflection yoke as the beam is scanned down the picture tube. The drive current
increases as the beam passes through the middle edge section of the tube.

Vertical Deflection Circuit

Note: Reference Figure 4-2 during troubleshooting descriptions.
Overview
Troubleshooting of the vertical deflection circuit will be the subject of this section. When the vertical section is
operating correctly, pulses are output from IC545/pin 3 and applied to System control section of IC001/pin78.
This signal tells System Control that the vertical drive IC545 is working properly. If the vertical section becomes
defective, the pulse from IC545/pin 3 will stop and obviously so will the pulses at IC001/pin 78. System Control
will now turn Off the AC Relay (RY600), and the Standby/Timer LED will flash four times, pause and repeat until
the defect is fixed.
8mHz
X001
3 4
ONE-CHIP
45
IC001
44
I-PROT
78
-
9
R532
+
10
IC565
R539
+
12
-
13
FIGURE 4-2 - VERTICAL DEFLECTION CIRCUIT
IC545
7 6 5
-13V
8
+13V
R541
14
R545
R542
R540
16
4. Deflection Circuits
4 3 2 1
CN585
R548
+13V
CN515
6
5
R543
4.2CTV30
VD+
6
TO CV
BOARD
VDY
3/27/02