Circuit Description - Goldstar OS-7020 Service Manual

7. CIRCUIT DESCRIPTION
The block diagram(page62) shows the overall relationship between
all of the circuits. Complete schematics of each circuit are
also given in section schematic diagrams (page63-to75)
Refer to these diagrams throughout the following circuit des-
cription for electrical values and relationship.
Channel 1
&
2 Vertical Preamp
j
Input signals for vertical deflection on the CRT can be connected
to the "CHl X" and{or) "CH2 ' i " input connectors.
In the X-Y mode of operation, CHl input signal provides the
horizontal(X-axis) deflection and CH2 input signal provides the
vertical(Y-axis) deflection.
The Channel 1 and 2 Vertical Preamp circuits provide control of
input coupling, vertical deflection factor, DC balance, Vertical
position and vertical gain.
They also contain a stage to provide a sample of the input signal
to the Tigger Preamp circuit for internal triggering from the
Channell and{or) Channel 2 signal only.
I
Vertical switching circuit
j .
The vertical switching circuit determines whether the CHl or CH2
or both Vertical Preamp output signals are connected to the
Vertical Output Amplifier circuit.
In the ALT and CHOP modes, both channels are alternately display-
ed on a shared time basis.
Vertical Output Amplifier
j
The Vertical Output Amplifier circuit provides the final amplifica-
tion for the signal before it is applied to the vertical deflection
plates of the CRT.
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