Hitachi 61HDX98B Manual page 17

BLOCK DIAGRAM EXPLANATION DEFLECTION BLOCK
The 61HDX98B deflection circuit differs from con-
ventional Hitachi product. It utilizes in a sense, two
horizontal output circuits. One for Deflection and on
for High Voltage. The notations around the Block dia-
gram will be described in a counter clock wise fashion
as best a possible.
CUT OFF:
Cut of collapses the Vertical circuit during I
alignments, during CRT Set Up.
2
I C:
Communication from the Sub Microprocessor I001
during sweep variations due to Standard/NTSC 480P
mode and 1080I High Definition mode.
ABL:
ABL voltage is generated by monitoring the current
through the flyback transformer. This voltage will
fluctuate down when the scene is bright and up when
the scene is dark. The ABL voltage will manipulate
the screen brightness and contrast to prevent blooming
under these conditions.
HV SYNC:
The composite sync is routed into the Sync processor
which determines the sweep condition for the signal
being provided.
H and V BLK:
Horizontal and Vertical Blanking is developed within
the Deflection circuit. The Horizontal Blanking pulse
operates around 13V P/P and is produced by taking a
sample pulse from the Deflection transformer T752.
The Vertical Blanking pulse is generated from the
Vertical output IC, I601 pin 7. This pulse normally
operates at 23V P/P.
IR:
The Infrared Pulses coming from the remote control
are routed through the Deflection PWB to the Digital
Convergence Unit. During DCAM (Digital Conver-
gence Adjustment Mode), the Remote Control pro-
vides manipulation pulses for the DCU.
DIG RGB BUSY:
This indicates Digital RGB and BUSY.
Digital RGB represents the on screen characters pro-
duced by the DCU for generating the Digital Conver-
gence adjustment grid and text produced during cer-
tain conditions such as Magic Focus, Sensor Initializa-
tion, Data Storage, etc...
Busy notifies the sub Microprocessor I901 which in
turn notifies the DM-1 module that the DCU has en-
tered the DCAM. During this time, the DM-1 module
ignores the remote control commands.
MAGIC SW:
When the customer presses the Magic Focus button on
the front of the set, it produces a command for the
2
C Bus DCU to begin the Magic Focus process.
D SIZE:
Digital Size is a control signal for raster enlargement
when MAGIC FOCUS is operated. Raster enlarge-
ment is required for the MAGIC FOCUS PATTERN
to hit the photo sensors.
This signal is output from DCU and input to the Sub
Microprocessor I901. The Sub Microprocessor con-
trols the I702 on the DEF.SUB PWB) for enlarging
raster size.
In case of AP-85, this control signal is called "A.
SIZE". It's the same function between DIG.SIZE and
A.SIZE.
S WIDE:
Smooth Wide is a condition entered through the Menu
by the customer while watching an NTSC 4X3 aspect
video source and the customer wants to fill the screen.
TO CONVERGENCE YOKES:
The DCU provides compensation signal for deflection
abnormalities to the convergence output IC. The Con-
vergence output IC in turn, amplify the signals and
rout them to the convergence yokes.
+26V, 26VP and RETRACE PULSE:
The positive 26V and the negative 26V is routed to the
Deflection transformer I752. They enter the trans-
former as a pure DC voltage. A 15V P/P horizontal
pulse is added to the DC voltage and leaves as +26VP
and –26VP. From here these voltages are routed to the
Convergence output section and they are rectified.
They become +33V and -33V respectively. This proc-
ess prevents the need for another power supply.
+B 130V:
The Deflection transformer receives the 130V V1 DC
source.
DF OUT:
Generated from the I702 on the Sub Deflection PWB
and the Horizontal Blanking pulses, a Dynamic Focus
waveform is created. This is a parabolic waveform that
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