Fostex B-16 - Page 23

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3)

R/P

amplifier

control

circuit

Operation

of

channel

1

only

will

be

explained

as

all

16

channels

operate

in

the

same

way.

When

an

ENCODE

signal

arrives

from

the

system

control

PCB,

Ul-1

goes

to

"L"

level

and

if

channel

1

of

the

record

selector

switch

is

depressed,

UI-

2

will

also

go

to

"L"

level.

Then,

Ul-3

and

U2-9

will

also

go

to

"L"

level,

the

R/P

amplifier

will

change

to

ENCODE

mode

and

channel

1

will

be

in

the

input

monitor

mode.

If

the

transport

is

in

the

REC-PLAY

mode

and

if

a

TRANSPORT

REC

signal

is

input

at

"L"

level

from

the

system

control

PCB,

(Jl-13

goes

to

"L"

level,

and

when

the

channel

1

of

the

record

selector

switch

is

depressed,

Ul-12

goes

to

"L"

level.

As

a

result,

Ul-11

goes

to

"L"

level,

U2-6

and

U2-9

also

to

"L"

level,

and

the

R/P

amplifier

will

go

to

the

ENCODE

mode.

Simultane



ously,

the

output

of

Ul-11

passes

through

the

integration

circuit

of

R4

and

C2,

and

after

a

certain

delay,

an

"H"

level

is

output

from

Ul-10.

This

switches

ON

the

REC

relay

in

the

R/P

amplifier.

The

output

of

Ul-10

is

delayed

by

R7

and

C3,

and

since

Ul-5

is

"L"

,

and

"L"

level

is

output

from

Ul-4

to

switch

ON

the

BIAS

ON/OFF

in

the

R/P

amplifier.

At

the

same

time,

this

signal

passing

through

D4

switches

OFF

Q6

to

switch

ON

the

MASTER

BIAS.

When

either

the

TRANSPORT

REC

signal

goes

to

"H"

or

the

RECORD

SELECTOR

is

switched

OFF,

Ul-11

goes

to

"H",

Ul-5

goes

to

"H"

,

and

Ul-4

also

to

"H"

,

and

thus

the

R/P

amplifier

BIAS

ON/OFF

signal

goes

to

OFF.

After

a

certain

delay

of

the

Ul-11

"H"

level

by

R4

and

C2

,

it

makes

Ul-10

go

to

"H"

level.

As

a

result,

the

REC

relay

is

switched

OFF.

The

output

of

Ul-10

also

delayed

by

R7

and

C3,

goes

to

U2-3,

4

which

results

in

"H"

level

output

from

U2-6

and

U2-9.

Due

to

this,

R/P

amplifier

goes

to

the

DECODE

mode.

The

operation

is

the

same

for

channels

2

through

16.

4.

S

Function

switch

(Function/Display)

SI

through

S16

are

the

RECORD

SELECTOR

switches

and

the

numbers

correspond

to

the

channel

numbers

1

through

16.

Di

through

D16

are

the

mode

display

LED's

for

the

RECORD

SELECTOR

switches.

Si

through

S16

are

2

circuit

2

contact

switches

with

one

circuit

used

for

the

SAFE/RDY

signal

and

the

other

used

for

LED

control.

Ql

and

Q2

make

up

a

constant

current

circuit

and

is

controlled

by

the

FUNCTION

LED

CONT

20

Other manuals for Fostex B-16

Owner's Manual20 pages