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The

vertical

sync

input

initiates

retrace

each

time

it

goes

low

(60

times

per

second).

However,

the

E301

is

capable

of

free-running

trace

and

retrace,

in

the

event

no

retrace

sync

signal

is

sensed

from

the

video

logic.

R302

and

C304

define

E30l

internal

free-running

oscillation

at

60

Hz

(~l

Hz).

At

the

start

of

a

vertical

trace,

E301

outputs

a

voltage

potential

on

pin

4.

This

potential

is

stabalized

and

output

to

the

vertical

output

circuit.

Feedback

from

that

circuit

is

input

to

E30l

at

pin

10.

This

feedback

is

applied

across

R306

and

compared

with

the

adjustable

(R307)

vertical

linearity

value

at

pin

1

of

E301.

The

feedback

at

pin

10,

and

the

value

at

pin

1

are

used

by

E30l

to

monitor

gain

and

to

compensate

for

any

drift

in

output

voltage

value.

The

output

potential

at

pin

4

of

E301

is

ramped

upward

throughout

the

trace

period.

At

vertical

retrace,

the

output

is

returned

to

zero,

removing

the

ramped

potential

from

the

vertical

output

circuit.

Current

regulation

on

the

output

of

E301

is

controlled

by

an

adjustable

regulator

(R303),

which

can

increase

or

decrease

the

height

of

the

area

of

the

screen

scanned

during

a

vertical

trace.

8.2.4.2

vertical

Output

Circuit

--

The

vertical

output

circuit

develops

the

potentials

used

to

drive

current

through

the

vertical

windings

of

the

yoke

assembly.

The

vertical

output

circuit

(Figure

8-16)

consists

of

the

following

circuits.

•

Voltage

divider

network

(R31l-R3l4

and

C309)

•

Yoke

current

drive

components

(C3ll,

C3l2,

R3l7,

and

Jl)

4.7K

'910

TO/FROM

{ ..

VERTICAL

PROCESSOR

----r--+----,----,

R312~

562K

1

~"O

C309

47

10V

C311

1000

R313

16V

47.5K

1%

R314 R315

1 1

TO

DYNAMIC

FOCUS

lC313)

PART

C312

OF

1000

Jl

16V

R317

100

1/1W 4

PART

OF

YOKE

ASSY

Figure

8-16

Vertical

Output

Circuit

Diagram

8-14

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