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DP-4X SIDE PINCUSHION CIRCUIT EXPLANATION
(See the Side Pincushion Circuit Diagram for details)
Due to the nature of deflection, the sides of the picture has a tendencies to pull in similar to an hour glass. The
Side pincushion circuit is responsible for manipulating deflection to compensate. This is accomplished by super
imposing a vertical parabolic waveform on the DC voltage utilized for Horizontal Size.
VERTICAL YOKE CHARGE PULSE: (See Vertical Output Circuit for details related to this pulse)
The pulse generated on the positive side of C607 is also routed through the parabolic wave form generation cir-
cuit of R616 and C606. Then to the PDD1 connector pin 3. Then to pin 6 of IB01. This IC then generates a Ver-
tical Parabolic signal that is sent to the side pincushion circuit from pin 10 and a Vertical parabolic signal to the
Dynamic Focus circuit from pin 18 and out the PDD1 connector pin 1 for corrections to focus DC voltage.
SIDE PIN WAVE FORM GENERATION IC:
The Vertical parabolic signal from pin 10 of IB01 is routed through RB39 to pin 2 of IB02. This is the negative
leg of the internal op-amp. Also attached to this input circuit is the Horizontal Size circuit comprised of a DC
level shift from pin 11 of IB01 to the base of QB05. This manipulates the Collector voltage which is sent to the
same pin. The Microprocessor communicates with IB01 via I2C (See the Microprocessor Data Communication
2
Circuit Diagram for I
C path) and can adjust the DC level at pin 2 of IB02. The output at pin 1 of the op-amp is
connected back to pin 2 via RB33 for stability.
The output of the DC offset voltage with Vertical parabolic waveform from I802 is output pin 1, then to pin 6. It
is then routed out pin 7, out the PPD1 connector pin 10 to the base of Q703. This transistor has its emitter off set
above ground by D713, R704 and R747 back to the SW +10.5V . This transistor drives the base of the Side Pin
Cushion modulator transistor Q701. The collector of Q701 is connected to the Deflection SW +115V. The hori-
zontal size DC offset voltage and Vertical parabolic side pin cushion compensation waveform is now super im-
posed on the SW +115V which is sent to the Deflection Transformer T701 and the Horizontal Linearity circuit
C715, L703, R729 and R756 to the Horizontal Yoke returns.
D SIZE SWITCH:
When Magic Focus is activated by either the Magic Focus button or customer's menu or during service when the
sensors are initialized, The Microprocessor I004 receives the D Size signal from the Digital Convergence Unit,
UKDG pin 35 then to the PDS2 connector pin 7. When the Microprocessor receives this signal at pin 43, it
knows to increases the Vertical size to allow positive contact of the light pattern hitting the sensors. It does this
2
by I
C data communications to IB01 which then manipulates the DC offset voltage for H size via pin 11 and ma-
nipulates the Vertical Size via the V Drive signal output pin 4. (See Vertical Output Circuit for details related to
Vertical Drive)
PAGE 05-09
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