Hitachi 51F510, Руководство пользователя, Страница: 75 / 152

DP-4X VERTICAL OUTPUT CIRCUIT EXPLANATION
PAGE 05-07
(See the Vertical Output Circuit for details)
I601 B+:
The Vertical Output IC I601 requires SW+28V to operated. This voltage is supplied from the Power Supply. The
output for the SW+28V pulse is from pin 16 of TP01 . Its then rectified by DP30 , filtered by CP32, LP30, CP34 .
The SW +28V is routed through the Vertical B+ Excessive Current Sensor R629 , Q604 to pin 7 of I601 .
TRIGGER PULSE:
The Vertical Drive Trigger pulse is routed from the Rainforest IC IY04 pin 35 on the Signal PWB. It is output to
the PDS2 connector pin 10 , to the Sub Deflection PWB PDD1 connector pin 4 . Then into pin 21 of IB01 . This
IC generates the Vertical Drive signal out pin 4 to the PDD1 connector pin 2 . Then to the Deflection PWB. It is
then sent to the Trigger Input on
I601
pin
6
.
During Trace, the internal Ramp Generator circuit using C602 connected to pin 5 as the time constant begins
charging. As it charges, the Pump Up circuit is also charging from the SW+28V to C605 , through pin 8 to an in-
ternal switch inside
I601.
When the Trigger pulse arrives (Retrace Time), the internal switch toggles over to the
output stage push pull pair inside I601 , and the +28V charged capacitor C605 discharges. The output stage push
pull pair inside I601 already have +28V input from pin 4 . So the output pulse from pin 3 is now near 50V p/p.
This is only needed for a short duration of time, (retrace) so the Charge Pump circuit eliminates the need for a
50V power supply.
(V BLK) VERTICAL BLANKING PULSE GENERATION:
When the Charge Pump discharges and produces the 50V p/p pulse for Vertical drive during retrace, this pulse at
pin
8 is also routed as the Vertical Blanking pulse. It’s amplitude is around 21V p/p and is sent to the following
circuits;
•
Vertical Sweep Loss detection circuit
•
Convergence circuit for vertical correction waveform generation
VERTICAL OUTPUT PULSE FROM I601:
The Vertical Output pulse from pin
3
is then routed to the Vertical Yokes generating a linear sawtooth current
which moves the beam. (Trace = from top to bottom, Retrace = from bottom to top). This linear current is gener-
ated by the charge time constant of the vertical yokes charging
C607 through the low ohm resistors R619 , R620 .
VERTICAL YOKE CHARGE 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 from pin
18
through
QB04
that is sent to the dynamic focus circuit for corrections to focus
and from pin 10 to IB02 pin 3 for side pincushion correction.
The pulse generated on the positive side of C607 is also routed back to I601 pin 4 . The AC component of this
signal is for vertical linearity compensation. The DC component of this signal is routed back to the Ramp genera-
tor circuit described above.
The Vertical height is now adjusted by I
2
C data communications to IB01 .
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 Micro. Receives this signal at pin
43
, it knows to in-
creases the Vertical size to allow positive contact of the light pattern hitting the sensors. It does this by I
2
C data
communications to IB01 .