Hitachi 61HDX98B Manual page 103

DEFLECTION TROUBLESHOOTING (Deflection and High Voltage Drive Signals)
IH01
Pin 12
13
This signal is then
routed to IH02 pin 10.
IH02 is the High Volt-
age Drive IC and regu-
lator.
By utilizing feedback
IH02
Pin 7
High
Voltage
Drive Sig.
15
voltage and the crossover point of the internally gener-
ated Sawtooth and outputs the signal shown in figure
15 from pin 7.
The output from IH02 pin 7 is sent through the pre-
drivers QH08 through
QH10 and is finally
delivered to the base
of QH01, the High
Voltage Horizontal
output Transistor.
The Deflection Hori-
zontal Pulse produced by Q777 is utilized by the High
Voltage section as it's drive signal. This signal must
be present for the High Voltage section to function.
This signal is routed to IH01 to be processed into the
actual drive signal for the High Voltage section.
HORIZONTAL WAVEFORMES COMPARED
TO H DRIVE
The Deflection H. Drive signal developed by Q755,
(See Figure 7) is routed to IH01 pin 1, (See Figure 11).
The following waveforms give a visual example of the
Signal Process as it eventually arrives at the base of
the Horizontal Output Transistor QH01, (See Figure
16).
Figure 17 illustrates the comparison of the waveform
From pin 4 it reenters
IH01 at Pin 10 and is
output again at pin 12.
IH02
Pin 10
14
voltage from the Focus
block assembly which
has been leveled shifted
by QH04 and QH05, the
internal comparator
makes a comparison
between the feedback
QH01
Base
16
supplied to Pin 1 of IH01 when compared to PDD1
Connector Pin 7 H. DRIVE signal.
Figure 17 illustrates the comparison of the waveform
input to Pin 1 of IH01 when compared to PDD1 Con-
nector Pin 7 H. DRIVE signal. This signal is also pro-
vided as an input to Pin 10.
The output of Pin 4 of IH01 is compared to Horizontal
Drive signal in Figure 18.
IH01 outputs this signal from Pin 10
17
18
19
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