Horizontal Output (Ea Board) - Sony BVM-1911 Operation And Maintenance Manual

3-15. HORIZONTAL OUTPUT (EA BOARD)
3-15-1. Horizontal Deflection Circuit
Horizontal drive pulse for Horizontal deflection output is made at
DA board and is fed to T4 ( Horizontal Drive Transformer) via Q l 3
1H. driver)_ T4 is driven by QI3 and output pulse of T4 drives Ql4
(Horizontal Output Transistor).
To obtain high efficiency in this model. DC-DC converter is used for
side pincushion correction, Horizontal Width adjustment and +B
Line voltage conversion to the horizontal deflection circuit.
This converted Line voltage is fed to horizontal deflection output
circuit via H.O.T (Horizontal Output Transformer). Side pincushion
correction and H. width adjustment are made by this DC-DC con-
verter. !Cl contains error amplifier and PWM (Pulse Width
Modula tor) circuit for DC-DC converter. Side pincushion correction
waveform and DC voltage for H. Width adjustment are made in DA
board and supplied to error amplifier to control DC-DC converter.
3-15-2. Horizontal Centering Circuit
±
low voltages power supply for H centering are made in this circuit
from output of secondary windings of TS ( Horizontal Output
Transformer). These low voltages are converted to current source
for mixing DC current on the deflection current. In this circuit Bow
shaped geometry distortion due to the H centering adjustment is
adjusted by providing vertical rate parabola waveform current on
the H centering current.
3-15-3. Horizontal Linearity Correction Circuit
Waveform for Horizontal Linearity correction made in DA board
is fed to SEPP amplifier (Single Ended Push Pull) which are com-
posed of Ql - Q5 transistors. Output of this amplifier is fed to H
deflection circuit (Deflection Yoke) and make correction of H
linearity by Tl (Horizontal Linearity Transformer).
3-35
BLOCK DIAGRAM OF EA BOARD
+150VO---~M
Q
11
DC - DC
CONVERTER
k
T3
HOT
SIDE
PIN.
~I
IC I
,I,) ___
,.-.;..;..._.1.--_-,i.--•
I
P.W .M
-
-------------------
-
Ql2
O.C.P
~
0
C
~
C
0
0
~
TS
HOT
I
§>
I
I
I
~--
I
I
I
QI
AFC
PULSE
IC 2
H.CENT
H.
n-J---L_ ____
...,..,-1--.:....:...:...r7 ___
_J
WIDTH
T
T4
HOT
013
,:~-
Ql4
H,DRIVE
H. DRIVE
PULSE
H.OUT
QIS ,16
H CENT
AMP
....
cs
H. LIN
WAVE
o' _____
.....,.,.'---Q-IH~--M-~-~N_. _
__,Jr------------------------~
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i
3-36
Tl
H LT
OUT)
AFC
PULSE
H DY