Murphy radio V310 User manual

V310,V310C

~

V310D

MURPHY

SERVICE

MANUAL

V310,

V310C

&

Y310D

Issued

by

MURPHY

RADIO

LTD

WELWYN

GARDEN

CITY

HERTS

Telephone:

WELWYN

GARDEN

3434

THE

V3

10,

V3

I

OC

&

V3

I

OD

TELEVISION

RECEIVERS

V310C

MAINS

SUPPLY:

CONSUMPTION;

AERIAL

INPUT

IMPEDANCE:

FREQUENCY

RANGE:

V310

V310D

SPECIFICATION

200-250

volts,

50

c/s

a.

c.,

or

200-250

volts

d.

c.

160

watts,

average

75

ohms,

unbalanced

Band

I

and

Band

III

INTERMEDIATE

FREQUENCY:

V1SlOn;

34.65

MC/S

Sound:

38.15

Mc/s

VALVES:

One

30L1,

one

30C1,

four

30F5,

two

6D2,

two

30FL1,

one

6/30L2,

one

30P16

(PL82)

or

30P12,

one

30P4,

one

U191,

one

U26

CATHODE

RAY

TUBE:

CRM172

Fuses:

F1:

2A

plain

cartridge

F2:

500mA,

Mag-Nickel

cartridge

LOUDSPEAKER:

V310,

V310C:

Elliptical,

6

in,

by

4

in.

permanent

magnet;

3

ohms

im-

pedance

V310D:

8

in.

diameter;

permanent

magnet;

3

ohms

impedance

OVERALL

DIMENSIONS:

V310:

17

in.

high,

19

in.

wide,

21

in,

deep

V310C:

31

in.

high,

21

in,

wide,

23

in,

deep

V310D:

33

in.

high,

22yz

in.

wide,

21

in.

deep

WEIGHT:

V310:

50

lb.

V310C:

60

lb.

V310D:

93

lb.

R

ELEnsED:

V310:

February,

1957

V310C:

April,

1957

V310D:

July,

1957

PRICE:

V310:

Standard

-

£51

15s.

6d.

plus

P.T.

V310:

Light

Wood

-

£52

2s.

lld.

plus

P.T.

V310C:

£60

6s,

lOd.

plus

P.T.

V310D:

£74

9s.

lld.

plus

P.T.

125711

2

V310,

V31OC,

&

V310D

TELEVISION

RECEIVERS

INSTALLATION

the

aerial

syste~.

Connect

the

aerial

to

the

receiver

with

7511

coaxial

cable.

Use

a

cross-

over

unit

if

two

separate

aerials

are

re-

quired.

Earth

the

receiver

by

means

of

the

upper

socket

on

the

aerial

escutcheon

if

time

-

base

radiation

is

suspected

or

if

local

inter-

fering

signals

are

being

received.

RECEIVER

ADJUSTMENTS

The

following

checks

and

adjustments

must

be

made

in

the

Customer's

house,

without

regard

to

any

made

elsewhere.

Ysins

voltage

adjustaent

A.C.

MAINS

200

TO

250V,

AND

D.C.

MAINS

220V

TO

250V

ONLY.

i.

Loosen

the

small

locking

knob

in

the

centre

of

the

mains

adjustment

dial

at

the

rear

of

the

receiver.

2.

Rotate

the

dial

so

that

the

desired

volt-

age

is

against

the

arrow

engraved

on

the

panel.

3.

Gently

press

the

dial

against

the

panel,

ensuring

that

the

two

pips

on

its

under-

side

locate

in

the

holes

in

the

panel.

4.

Whilst

still

maintaining

the

pressure,

tighten

up

the

locking

knob.

NOTE:

Wherever

possible,

arrange

the

mains

plug

connections

so

that

the

chassis

is

at

the

mains

neutral

potential.

D.C.

MAINS

200V

AND

210V

ONLY.

1.

Use

the

procedure

described

above,

but

first

set

the

dial

to

the

220V

d.

c.

posi-

tion,

and

correct

the

polarity

of

the

mains

connections

if

necessary.

Then

ro-

tate

the

dial

to

the

200V

or

210V

d.

c.

position

as

required.

The

above

procedure

is

necessary

because

the

rectifier

(MR

1)

is

out

of

circuit

on

these

taps,

and

the

fuse

(F1)

could

easily

'blow".

V810

and

V310C

On

-Off

Switch.

The

on

-off

switch

is

operated

automatically

by

a

spring

loaded

mechanism

when

the

release

button

at

the

top

of

the

cabinet

is

pressed.

Initial

test.

Check

that

the

receiver

is

operating,

but

do

not

leave

the

BRIGHTNESS

control

turned

up

if

it

is

suspected

that

the

ion

trap

magnet

is

not

in

its

correct

position.

Sensitivity

adjnstaent.

Connect

the

aerial

and,

for

optimum

signal

to

noise

ratio,

pro-

ceed

as

follows;

(a)

Set

the

STATION

SELECTOR

to

the

appro-

priate

position,

i.e.

B.B.C.

or

I.T.A.,

and

turn

the

volume

control

to

maximum

(fully

clockwise).

(b)

Adjust

the

local

oscillator

core

through

the

hole

the

STATION

SELECTOR

knob

using

(early

sets)

a

small

screw-

driver,

or

(later

sets)

the

plastic

trim-

ming

tool

supplied.

Exert

sufficient

pressure

on

the

tool

for

it

to

engage

with

the

oscillator

core

and

then

rotate

the

core

for

maximum

sound

output.

(c)

With

the

CONTRAST

control

at

minimum

(anti

-clockwise)

adjust

the

appropriate

SENSITIVITY

control

so

that

the

picture

is

only

just

synchronising.

It

will

be

necessary

to

increase

the

brightness

so

that

this

can

be

readily

ascertained.

(d)

Set

the

black

level

of

the

picture

by

means

of

the

BRIGHTNESS

control

and

ad-

just

the

CONTRAST

control

to

give

a

cor-

rectly

contrasted

picture.

In

areas

of

high

signal

strength,

if

cross

modulation

(picture

on

sound,

sound

on

pic-

ture,

or

heterodyne

patterns)

occurs,

repeat

this

procedure

with

the

CONTRAST

control

at

approximately

half

travel

instead

of

fully

anti

-clockwise,

check

afterwards

that

ade-

quate

picture

brilliance

is

obtained

with

the

CONTRAST

control

turned

fully

clockwise.

NOTE:

If

the

signal

is

so

strong

on

one

channel

that

it

is

impossible

to

adjust

the

SENSITIVITY

control

so

that

the

picture

is

just

synchronizing,

or

if

cross

modulation

is

still

present,

a

turret

attenuator

should.

be

fitted;

see

page

26.

V310,

V310C,

&

V310D

TELEVISION

RECEIVERS

3

MAINTENANCE

ADJUSTMENTS

To

enable

the

performance

to

be

kept

at

its

best

the

adjustments

described

in

the

following

three

sections

must

be

checked

and

cor-

rected

where

necessary

whenever

the

receiver

is

overhauled

or

re-

paired.

These

adjustments

should

not

be

necessary

on

installation.

I.

PICTURE

ADJUSTMENTS

The

procedure

is

normal

but

the

following

points

should

be

noted:

Tilted

Dicture.

The

cabinet

must

be

removed

from

the

chassis

for

this

adjustment.

The

scan

assembly

is

locked

in

position

and

ad-

justed

by

the

hexagonal

headed

brass

screw

at

the

top

of

the

housing.

Picture

position.

This

is

adjusted

by

the

black

insulated

lever

projecting

from

the

rear

of

the

focus

assembly,

and

through

the

back

of

the

cabinet.

Unscrew

the

lever

by

about

one

turn

and

then

move

it

as

required

to

centre

the

picture.

Tighten

after

use.

Line

linearity.

With

the

slider

at

the

top

of

its

travel,

i.e.

nearest

the

coil,

move

the

slider

down

slowly

until

the

equidistant

vertical

divisions

of

the

picture

or

test

pattern

are

as

near

to

equal

as

possible.

It

should

be

noted

that

the

correct

position

for

the

slider

should

be

near

the

top;

any

other

position

will

give

reduced

line

ampli-

tude.

2.

MECHANICAL

ADJUSTMENTS

Read

the

preliminary

note

above

Pocus

snit

position.

Whe❑

a

new

c.

r.

t.

is

fitted,

it

may

be

necessary

to

reposition

the

focus

unit.

To

do

this,

slacken

the

four

screws

visible

through

the

slots

in

the

side

of

the

large

supporting

cylinder,

and

slide

the

assembly

backwards

or

forwards

until

the

distance

between

the

c.

r.

t.

grid

plane

and

the

plate

at

the

rear

of

the

focus

unit

is

approximately

3/4

in.

(see

Fig.

1

)

with

the

focus

adjustment

fully

clockwise.

If

the

distance

is

much

less,

the

scanning

spot

wild

be

large;

if

it

is

appreciably

greater,

un-

even

focus

over

the

picture

area

will

result.

Before

retightening

the

screws,

make

sure

that

the

back

plate

is

at

right

angles

to

the

c.r.t.

neck.

Finally,

check

the

adjust-

ment

of

the

ion

trap

magnet,

as

described

in

"Electrical

Adjustments~~

below.

With

the

focus

knob

in

the

position

of

optimum

focus,

the

fixing

lugs

for

the

knob

should

be

more

than

3/4

in.

from

either

end

of

their

maximum

travel,

as

measured

around

the

outside

of

the

cylindrical

housing.

If

the

lug

is

closer

to

the

end

of

its

travel,

when

the

h.

t.

and

e.h.t.

voltages

are

normal,

and

the

unit

is

correctly

positioned,

the

focus

unit

may

be

suspected

of

having

an

incorrect

flux

density.

3.

ELECTRICAL

ADJUSTMENTS

Read

the

preliminary

note

above

Ion

trap.

To

assist

in

adjusting

the

ion

trap

magnet

it

should

be

roughly

positioned

on

the

neck

of

the

c.

r.

t.

so

that

the

paint

spot

is

towards

the

rear

of

the

receiver

and

the

two

grooves

in

the

rim

are

approximately

90

degrees

anti-clockwisefrom

the

c.r.t.

e.

h.

t.

connector,

looking

from

the

rear

of

the

re-

ceiver.

To

prevent

damage

to

the

c.

r.

t.

when

aa-

justing

the

position

of

the

magnet,

the

cathode

current

must

not

be

allowed

to

exceed

about

lOpA,

and

the

following

procedure

should

be

used.

1•

Remove

the

focus

adjusting

knob.

2.

Connect

a

meter

having

a

full

scale

de-

flection

of

1mA

or

less,

across

R153

(220

4

V310,

V310C,

&

V310D

TELEVISION

RECEIVERS

CENTRING

,

'

TILT

—

In

_

GRID

ION

TRAP

MAGNET

V

310

FOCUS

UNIT

FIXING

SCREWS

C.R.T.

FRONT

ADJUSTER

~

_

h

~•

C.R.T.

CLAM

PING

SCREW

1

C.R.T

FRONT

ADJUSTER

7

IN.

FRONT

MOULD

MARK

ON

C.R.T.

Fig.

1.

Side

view

RA)

oa

the

c.r.t.

base

connector

(+ve.

lead

to

Din

11).

3•

Turn

the

BRIGHTNESS

control

to

minimum

(fully

anti

-clockwise).

4.

Switch

the

receiver

"On"

and

allow

a

few

minutes

for

it

to

warm

up.

5•

Rotate

the

BRIGHTNESS

control

until

the

meter

reading

is

about

10µA.

g.

Position

the

ion

trap

magnet

so

that

its

forward

edge

is

just

behind

the

c.r.t.

grid

Dlane.

Slowly

rotate

the

magnet

for

maaimum

screen

brightness.

7.

Keep

the

magnet

at

right

angles

to

the

neck

of

the

c.

r.

t.

and

move

it

slightly

backwards

and

forwards

to

find

the

posi-

tion

at

which

maximum

screen

brightness

is

produced.

8.

Make

a

final

check

of

the

magnet

position

with

the

CONTRAST

and

BRIGHTNESS

controls

adjustedto

give

a

normal

viewing

picture.

B,eceiwer

oscillator.

There

is

no

Fine

Tuner

on

this

receiver

and

the

appropriate

oscil-

lator

core

must

be

adjusted

on

each

channel.

If

sore

than

one

peak

is

obtained,

select

of

the

receiver.

the

one

which

occurs

when

the

core

is

first

entering

the

coil

former.

To

make

this

ad-

justment

proceed

as

follows:

1•

Set

the

VOLUME

control

to

maximum

(clock-

wise).

2.

EARLY

SETS.

Insert

a

small

screwdriver

in

the

hole

to

the

right

of

the

STATION

SE-

LECTOR

knob

and

adjust

for

maaimum

sound.

To

do

this,

it

will

be

necessary

to

exert

a

slight

Dressure

on

the

screwdriver

and

press

the

oscillator

core

driver

down

for

a

distance

of

about

g/4

in.

Gentle

rota-

tion

will

cause

the

driver

to

engage

with

the

slot

in

the

coil

core,

which

can

now

be

tuned

for

maximum

sound

output.

LATER

SETS.

Insert

the

long

plastic

trim-

ming

tool

(Driver,

Part

No.

77219

supplied

to

all

dealers)

into

the

hole

to

the

right

of

the

Station

Selector

knob,

press

it

gently

downwards

and

rotate

it

a

little

until

it

engages

with

the

oscillator

coil

core,

and

then

adjust

the

core

for

maximum

sound

output.

Remember

to

partially

with-

draw

the

tool

before

turning

the

Station

Selector

to

another

position.

V310,

V310C,

&

V310D

TELEVISION

RECEIVERS

M

ECHAN

ICAL

NOTES

Reeoving

the

c.

r.

t.

Lay

the

receiver

on

its

face

and

remove

the

cabinet

from

the

chassis.

Remove

the

focus

knob,

the

c.r.t.

base

con-

nector,

the

ion

trap

magnet

and

the

c.r.t.

anode

connector.

Detach

the

moulded

frame

with

the

mask

and

safety

glass,

and

then

re-

turn

the

chassis

to

its

normal

upright

posi-

tion.

Slacken

the

two

c.r.t.

clamping

screws

and

ease

the

c.r.t.

out

of

the

chassis:

in

some

cases

it

may

be

necessary

to

slacken

the

four

screws

which

secure

the

c.r.t.

clamping

ring

to

th@

chassis

stays.

Refitting

the

c.r.t.

Fit

the

c.

r.

t.

into

the

chassis,

ensuring

that

the

anode

connector

is

on

the

same side

as

the

line

output

trans-

former,

then

proceed

as

follows.

NEW

C.R.TS.

Slacken

the

four

screws

which

securethe

c.r.t.

clamping

ring

to

the

chassis

stays,

and

tighten

the

c.r.t.

clamping

ring,

checking

that

the

distance

between

the

front

edge

of

the

c.r.t.

clamping

ring

cushion

and

the

front

"mould"

mark

on

the.c.r.t.

is

3/16

in.

Lay

the

moulded

frame,

with

the

mask

and

safety

glass,

on

a

flat

surface,

and

place

the

receiver

over

it,

so

that

the

c.r.t.

.fits

into

the

mask;

replacethe

four

fixing

screws

which

secure

the

frame•

to

the

chassis

stays.

Then

move

the

c.r.t.

as

required

to

position

it

squarely

in

the

mask,

so

that

it

makes

a

dust

tight

seal

and

tighten

the

four

screws

securing

the

clamping

ring

to

the

chassis

stays.

Refit

the

e.

h.

t.

connector,

the

ion

trap

magnet,

and

the

c.r.t.

base

connector.

ORIGINAL

C.R.T.

Tighten

the

c.

r.

t.

clamping

ring

checking

that

the

distance

between

the

front

edge

of

the

c.r.t.

clamping

ring

cus-

hion

and

the

front

mould"

mark

on

the

c.r.t.

is

3/16

in.

Lay

the

frame,

with

its

mask

and

safety

glass

on

a

flat

surface,

and

place

the

receiver

over

it,

so

that

the

c.r.t.

and

rubber

mask

form

a

dust

tight

seal.

Replace

the

four

frame

fixing

screws.

Refit

the

e.

h.

t.

connector,

the

ion

trap

magnet,

and

the

c.r.t.

base

connector.

Removing

the

line

output

transformer.

Take

off

V15

Polythene

anode

connector

and

the

top

connectors

of

V13

and

V14.

Remove

V15

and

detach

its

holder

complete

with

mounting

panel

by

removing

the

single

4BA

screw

and

nut.

Unsolder

the

YELLOW

lead

from

thetrans-

former,

and

then

the~8

remaining

leads

from

the

transformer,

noting

their

points

of

con-

nection.

Remove

the

line

output

transformer

c

lamp.

The

control

escutcheon.

If

the

control

escut-

cheon•

is

to

be

replaced,

care

must

be

taken

when

fitting

it,

to

make

sure

that

the

centre

line

which

is

visible

at

the

rear

of

the

moulding

coincides

with

the

centre

line

at

the

top

of

the

fibre

back

of

the

cabinet.

The

c.

r.

t.

frame.

In

the

event

of

the

thread

in

a

brass

insert

at

a

corner

of

the

moulded

frame

becoming

damaged,

use

a

self

tapping

screw,

type

PK6Y

by

3/8

in.

P.R.H.

Part

No.

103903,

in

the

alternative

hole

provided.

The

top

controls.

The

following

information

is

given

to

assist

in

the

choice,

from

exis-

ting

stocks,

of

suitable

replacements

for

the

variable

controls

at

the

top

of

the

re-

ceiver.

In

Fig.

2,

the

dimension

"A"

refers

to

the

overall

spindle

length

and

is

measured

from

the

end

of

the

spindle

to

the

mounting

face,

i.e.

the

face

of

the

control

which

makes

contact

with

the

receiver

control

panel.

CONTROL

DIM.

"A"

LAW

RESISTANCE

Brightness

1

in.

Lin.

100K11

1

(R64)

Contrast

1

13/16

in.

Lin.

100KS1

(R28)

V310,

V310C

Contrast

1

in.

Lin.

100Kf1

(R28)

V310D

only

Volume

(R96)

Y310,

V310C

1

in.

Rev.

log.

250Kf1

Volume,

On-

Off

(R96)

V310D

only

1

13/16

in.

Log.

250K(1

with

d.p.

switch

Removing

the

voltage

selector

tnob.

Unscrew

the

small

locking

knob

and

remove

the

circlip

Fig.

2.

6

V310,

V310C,

&

V310D

TELEVISION

RECEIVERS

which

is

now

visible.

Unsolder

the

ORANGE

lead

from

the

contact

nearest

the

centre

on

the

underside

of

the

voltage

selector

panel.

Withdraw

the

dial

(knob,

printed),

complete

with

its

contacts,

away

from

the

spindle.

To

refit,

reverse

the

above

procedure.

Removing

the

focus

unit.

Withdraw

the

chassis

from

the

cabinet.

Then

remove

the

focus

knob,

the

c.r.t.

base

connector

and

the

ion

trap

magnet.

Slacken

the

four

focus

unit

fix-

ing

screws

(two

pairs)

which

are

accessible

through

the

two

slots

i.n

the

upper

half

of

the

scan

coils

housing

and

withdraw

the

focus

unit

complete

with

the

Centring

control

mec-

hanism.

Removing

the

scan

coils

assembly.

Withdraw

the

c.r.t.

from

the

chassis.

Then

remove

the

scan

coils

assembly

locking

screw

at

the

top

of

the

cylindrical

housing,

slacken

the

three

brass

screws

and

disengage

the

mounting

ring

from

the

slots

in

the

housing.

The

scan

coils

assembly

can

now

be

withdrawn

and

the

leads

disconnected.

THE

TUNER

UNIT

The

"stray"

capacitance

of

the

components

and

wiring

forms

a

large

part

of

the

tuning

capacitance

acr.ass

the

aerial,

r.

f.

t.

and

oscillator

coils.

Every

effort

must

therefore

be

made,

when

replacing

components

or

wiring,

to

ensure

that

the

lengths

of

the

leads

and

the

positions

of

the

components

follow

the

original

as

closely

as

possible.

Take

care

also

with

the

"dressing"

of

leads

and

fit

sleeving

wherever

necessary

to

avoid

short

circuits

across

tags,

particularly

on

the

.valve

holders.

IMPORTANT.

It

must

be

clearly

understood

that

any

repair,

or

the

replacement

of

any

component,

makes

the

realignment

of

any

unit

essential.

Any

attempt

to

carry

out

work

on

the

unit,

without

subsequent

realignment,

can

only

lead

to

a

deterioration

of

the

per-

formance,

particularly

on

Band

III.

To

remove

the

osc.

core

driver

(early

sets

only,

see

Modifications).

Turn

the

Station

Selector

to

a

position

in

which

there

are

no

coils,

remove

V6.

.and

then

remove

the

top

end

of

the

driver

from

the

plastic

guide

by

pres-

sing

it

downwards

through

the

wide

end

of

the

slot

in

the

slotted

arm

(stop

for

driver,

74'786).

Withdraw

the

lower

end

of

the

driver

from

the

guide

on

the

tuner

unit,

taking

care

not

to

lose

the

brass

sleeve

(eyelet,

split

4774)•

Do

not

attempt

to

move

the

guide

on

the

tuner

unit;

this

has

been

carefully

assembled

in

the

factory

so

that

the

driver

will

always

engage

with

the

coil

cores.

To

remove

the

tuner

unit.

Record

the

lead

positions

and

then

proceed

in

the

following

manner:

1.

Disconnect

the

six

leads

and

the

resistor

from

the

tags

on

the

outer

side

of

the

receiver

chassis

and

the

tuner

unit.

2.

Disconnect

the

wire

from

the

lead

—through

capacitor

at

the

end

of

the

unit,

and

the

coaxial

lead

from

the

aerial

escutcheon.

Do

not

disconnect

any

of

these

leads

from

within

the

tuner

unit.

3.

Unscrew

the

switch

wafer

and

withdraw

it

from

the

end

of

the

unit;

on

early

sets,

remove

the

osc.

core

driver

as

described

above.

4.

Remove

the

three

fixing

screws

on

the

outer

side

of

the

receiver

chassis

and

withdraw

the

unit.

Take

care

not

to

mislay

the

link

from

the

Station

Selector

shaft

which

becomes

disengaged

when

the

tuner

unit

is

removed.

NOTE.

When

refitting

the

tuner

unit,

ensure

that

the

switch

wafer

and

rotor

are

cor-

rectly

positioned

at

the

end

of

the

unit.

This

can

be

checked

by

observing

that

the

appropriate

Sensitivity

control,

i.e.

B.B.C.

or

I.T.A.

,

is

switched

into

circuit

at

the

corresponding

settings

of

the

Station

Selector

knob.

Identifying

the

coil

strips.

The

aerial

coil

strips

have

four

contacts

and

are

shorter

than

the

oscillator

coil

strips

which

have

six

contacts.

According

to

the

frequency

channels

for

which

they

are

intended,

the

coil

strips

are

marked

with

spots

of

coloured

paint

using

the

resistor

colour

code,

i.e.

BROWN

for

Channel

1,

RED

for

Channel

2

etc.

Channel

10

coils

however,

will

have

CH10

printed

on

the

coil

strip.

An

additional

GREEN

code

spot

is

added,

so

that

the

coils

for

the

V310

series

can

be

identified

from

those

of

earlier

receivers.

Removing

s

coil

strip.

Press

back

the

holding

spring

and

carefully

lift

out

the

coil

strip

by

gripping

between

the

thumb

and

fore-

finger,

the

end

remote

from

the

spring.

Fitting

a

coil

strip.

Press

back

the

holding

spring

and

fit

the

coil

strip

by

pressing

its

slotted

end

against

the

holding

spring

and

then

guiding

its

other

end

into

the

slot

at

the

middle

of

the

turret.

Turret

locating

mechanism.

To

adjust

the

mechanism

while

the

tuner

unit

is

still

in

position

on

the

receiver

chassis,

proceed

as

follows:

1.

Remove

the

c.

r.

t.

from

the

chassis

as

described

on

page

5

.

2.

Remove

the

side

screens

from

the

tuner

unit,

and

loosen

the

screw

holding

the

locating

spring

(it

will

be

necessary

to

remove

certain

valves

to

gain

access

to

these

screws).

3.

With

the

locating

roller

correctly

located

in

a

groove

on

the

turret,

slowly

turn

the

turret

until

the

coil

contacts

are

in

the

middle

of

the

fixed

contacts,

and

then

re

-tighten

the

locating

spring

fixing

screw.

4.

Turn

the

turret

to

all

its

other

positions

V310,

V310C,

&

V310D

TELEVISION

RECEIVERS

to

confirm

that

the.

location

is

satisfac-

tory,

and

then

replace

the

side

screens,

valves,

and

c.

r.

t.

Lead

-through

capacitors.

If

a

lead

-through

capacitor

has

to

be

replaced,

the

faulty

one

can

be

removed

by

applying

heat

to

the

metal

screen

immediately

around

the

capacitor

body.

When

the

solder

is

sufficiently

soft,

with-

draw

the

capacitor

from

the

metal

screen,

from

the

same

side

as

the

soldered

connection

to

the

metal

screen.

Trimming

capacitors.

If

a

trimmer

screw

has

been

accidentally

unscrewed

fully,

or

if

a

trimmer

body

has

to

be

replaced,

the

refit-

ting

should

be

carried

out

as

follows:

Thread

the

trimmer

nut

on

to

the

trimmer

screw,

with

the

convex

side

of

the

nut

to-

wards

the

head

of

the

trimmer

screw,

and

en-

gage

the

screw

in

the

threaded

trimmer

body.

Press

the

trimmer

body

against

the

chassis,

making

sure

that

the

square

end

of

the

trim-

mer

locates

with

the

square

hole

in

the

chassis,

and

turn

the

trimmer

screw

until

about

half

of

its

length

is

engaged

in

the

trimmer

body.

while

still

holding

the

trim-

mer

body

against

the

chassis,

prevent

the

screw

from

turning

and

rotate

the

nut

until

it

presses

tightly

against

the

chassis.

While

still

preventing

the

screw

from

turning,

in-

crease

the

pressure

of

the

nut

on

the

screw

by

rotating

the

nut

one

half

-turn

more

in

a

clockwise

direction..

The

correct

degree

of

pressure

is

now

applied

to

prevent

the

trim-

mer

screw

from

turning

when

subjected

to

vibration.

Labrication.

During

the

course

of

assembly,

the

contacts

and

Station

Selector

(turret)

mechanism

on

the

tuner

unit

are

lubricated.

The

contacts

on

the

coil

strips

are

smeared

with

petroleum

jelly

(Vaseline)

and

the

locator

roller

and

the

spindle

assembly

are

treated with

a

medium

-bodied

grease.

When

servicing

the

tuner

unit,

it

may

be

necessary

to

replenish

this

lubrication,

particularly

on

the

coil

-strip

contacts

which

will,

no

doubt,

have

been

handled

and

the

petroleum

jelly

thereby

removed.

Cleaning

the

contacts.

The

indiscriminate

application

of

any

of

the

proprietary

brands

of

switch

-cleaning

fluid

is

strongly

depre-

cated.

If

the

cleaning

of

any

of

the

contacts

is

necessary,

a

local

application

of

the

cleaner

-

with

a

small

brush

-

should

be

all

th

at

is

required.

Afterwards,

a

smear

of

petroleum

jelly

must

be

applied

to

those

contacts

which

have

been

cleaned.

V310D

RECEIVERS

Idains

On/Off

Switch.

This

switch

is

ganged

with

the

volume

control

in

the

conventional

manner,

the

top

flap

on

the

cabinet

serving

only

as

a

protective

cover

for

the

controls.

C.r.t.

position.

With

the

chassis

correctly

located.in

the

cabinet

the

corners

of

the

c.r.t.

should

be

just

flush

with

the

wooden

frame

in

the

cabinet.

Ensure

that

the

dust

tight

seal

is

in

its

correct

position.

Re®oving

tLe

safety

glass.

First

remove

the

chassis

from

the

cabinet.

Remove

the

rubber

"stops"`at

the

rear

of

each

lower

channel

and

slide

back

each

door

to

the

maximum.

Take

out

the

three

screws

holding

the

wooden

retaining

strip

at

the

upper

edge

of

the

front

of

the

safety

glass

and

remove

the

strip.

Remove

the

glass,

by

lifting

its

lower

edge

clear

from

the

retaining

groove.

Removing

a

door

(Tambour)

or

handle.

Remove

the

safety

glass,

and

the

c.r.t.

surround

complete.

The

handles

can

then

be

removed

by

unscrewing

the

four

fixing

screws.

Slide

out

the

doors

towards

the

rear,

coiling

the®

in

the

space

available.

The

doors

may

be

re-

placed

in

a

similar

manner.

If

the

receiver

is

to

remain

in

use

tem-

porarily

without

the

doors,

these

can

be

re-

moved

without

disturbing

the

safety

glass

or

c.r.t.

surround

simply

by

taking

out

the

two

rear

"stops"

and

easing

the

handles

through

the

gap

at

each

side

of

the

front

of

the

cabinet.

This

process

cannot

easily

be

re-

versed,

however.

CIRCUIT

DESCRIPTION

This

is

a

superheterodyne

type

of

receiver

designed

for

the

reception

of

any

two

channels

in

Band

I

and

any

two

channels

in

Band

III.

It

has

r.f.

,

frequency

changer

and

1st

i.f.

circuits

that

are

common

to

both

the

sound

and

vision

signals;

channel

selection

is

by

means

of

a

four

position

rotary

coil

turret

The

r.f.

stages.

A

double

triode

cascode

amplifier

is

employed,

followed

by

a

triode

pentode

frequency

changer

stage.

Since

the

r.f.

coils

are

adjusted

to

within

very

close

limits

during

manufacture,

the

circuits

are

aligned

by

adjusting

the

residual

capaci-

tances

at

a

single

Band

III

frequency;

the

alignment

then

holds

for

all

channels

in

both

bands.

A

Fine

Tuner

is

not

fitted

to

this

receiver,

and

therefore,

the

oscillator

coils

must

be

carefully

tuned

on

installation.

A

sound

i.f.

rejector

(Li0/C10),

which

is

in

circuit

on

all

channels,

is

included

in

the

tuner

unit.

The

vision

i.f,

stages.

The

first

i.f.

amp-

g

V310,

V310C,

&

V310D

TELEVISION

RECEIVERS

lifier

after

the

frequency

changer,

is

common

to

both

sound

and

vision

signals..

The

Con-

trast

controlis

in

the

grid

-cathode

circuit

of

this

valve,

and

the

sound

i.f. signalis

taken

from

the

anode.

Another

stage

of

vision

i.f. amplification

follows,

and

feeds

the

vision

detector.

There

are

threerejectors

in

the

vision

i.f. amplifier;

L13/C41,

L14/

C46

(own

sound

i.f. rejectors),

and

L15/C50

(adjacent

sound

i.f. rejector).

The

vision

detector

and

video

stages.

One

half

of

a

double

diode

valve

(V5)

is

used

for

detection,

and

the

rectified

signalis

fed

via

the

i.f, stopping

choke

(L18)

and

the

grid

compensating

choke

(L19)

to

the

grid

of

the

video

amplifier

valve

(V6).

The

cathode

circuit

of

this

valve

includes

a

3.5

Mc/s

rejectorcircuit

(L20,

C53)

to

remove

the

beatpattern

caused

by

any

sound

carrier

which

might

pass

the

i.f, rejectors;fixed

video

response

correctionisalso

provided

by

C54.

The

output

from

the

anode

of

V6

is

fed

to

the

vision

interferencelimiter,

the

cathode

of

the

c.r.t.

via

a

series

compensa-

ting

choke

(L21),

and

the

synchronizing

sig-

nal

separator

circuit.

The

synchronizing

signal

circuits.

The

video

signal

from

V6

anode

is

applied

to

the

con-

trol

grid

of

a

conventional

sync.

separator

(V7

a)

which

suppresses

the

picture

modulation,

so

that

a

"negative

going"

sync.

pulse

wave-

form

appears

across

the

anode

resistor

(R71).

The

pulse

voltage

is

taken

to

V13

in

the

line

time

-base

and,

afterdifferentiation

by

C63

and

R79,

to

the

grid

of

the

frame

"sync".

separator

(V7b).

A

further

output

is

taken

to

the

cathode

of

V7b

via

R77,

to

keep

the

valve

biased

back

during

the

picture

period.

The

initial

frame

pulse

charges

C66

in

V7b

anode

circuit,

so

that

subsequent

pulses

are

reduced

in

amplitude.

The

resultis

an

initial

frame

synchronizing

pulse

of

high

amplitude

and

having

a

steepleading

edge,

with

the

remaining

pulses

markedly

reduced.

These

pulses

are

fed

to

the

main

charging

capacitor

(C93).

D.C.

for

V7b

is obtained

from

V12

cathode

circuit.

The

line

output

stage.

A

single

valve

wave-

form

generator

and

amplifieris

,used.

Its

mode

of

operation

is

conventional

except

for

the

method

of

increasing

the

output

effici-

ency.

This

is

achieved

in

the

following

man-

ner.

During

the

"flyback"

period

a

large

nega-

tive

potentialis

developed

in

the

screen

grid

winding

of

T3.

This

voltage

pulseis

integrated

and

fed

to

the

controlgrid

of

the

line

output

valve

(V13)and.hoidsthe

valve

inoperative

for

approximately

the

firstthird

of

each

line

scanning

period.

Scanning

is

obtained

during

this

period

by

arrangingthat

the

efficiency

diode

(V14)

conducts

and

allows

the

energy

contained

in

the

scan

coilstodrive

a

currentvia

V14

into

C109.

The

direction

of

thiscurrent

is

such

as

to

supply

the

initialpart

of

the

total

scan.

Frame.

time

-base.

This

consists

of

a

multivi-

brator

followed

by

a

pentode

output

valve.

A

secondary

circuit

on

the

output

transformer

supplies

a

suitable

wave

-form

for

frame

fly-

back

suppression,

which

is applied

to

ttie

first

anode

of

the

c.r.t.

Power

supply.

A

conventional

a.

c./d.c.

power

supply

circuitis

used,

and

the

valve

heaters

are

arranged

in

a

single

0.3

Amp.

series

chain.

On

the

lower

d.

c.

steps

of

the

mains

adjustment

switch,

the

rectifier

is

removed

from

the

circuit

to

avoid

an

unnecessary

loss

oP

h.

t.

voltage.

At

the

same

time,

thereser-

voir

capacitoris

disconnected

from

the

cir-

cuit

so

thatthere

isless

surge

current

to

'°blow"

the

mains

fuse;

see

"Installation"

on

page

2

.

VOLTAGE

READINGS

General.

The

voltage

readings

given

in

the

circuit

diagrams

and

chassis

layout

diagrams

arerepresentative

only,

and

willdiffer

slightly

from

one

setto

another.

Procedure

for

measuring

the

voltages.

To

ob-

tain

voltage

readings

corresponding

to

those

quoted

in

thecircuit

and

chassislayout

diagrams,

proceed

as

follows:

1.

Adjust

the

mains

adjustment

switch,

if

necessary,

to

suit

the

mains

input

at

the

time

of

measurement.

See

"Installation"

on

page

2

.

2.

Adjust

the

receiver

to

give

a

normal

pic-

ture

on

a

B.B.C.

channel.

3.

Measure

the

voltages,

using

a

20,OOOi1/V

meter.

If

a

20,00011/V

meter

is

not

avail-

able,

a

50011/V

meter

can

be

used;

those

readings

which

were

found

to

differ

appre-

ciably

from

the

figures

on

the

diagrams,

when

using

such

a

meter,

are

given

in

Table

1.

4.

Ascertain

whether

the

variablecontrols

are

having

the

correct

effect

on

the

volt-

ages

which

they

influence.;

follow

the

pro-

cedure

outlined

in

Table

2.

8.

h.

t. voltage.

This

was

taken

with

an

elec-

trostatic

voltmeter.

A

l0V

d.c.

meter

having

a

sensitivity

of

20,OOOII/V,

with

a

suitable

multiplier

such

as

the

AVO

25,OOOV

Multiplier

TYPe

8,

can

be.

used.

NOTE:

The

BRIGHTNESS

control

must

be

turned

to

zero

brightness

when

taking

this

reading.

Vision

and

sound

i.f. circuits.

If instabi-

lityis

experienced

when

measuring

the

anode

voltages,

connect

the

meter

instead

to

the

V310,

V310C,

&

V310D

TELEVISION

RECEIVERS

h.

t.

+ve

end

of

the

i.f.t.

primary

winding.

Strong

and

weak

signal

conditions.

Where

valve

electrode

voltages

are

affected

by

the

TABLE

I

Readings

which

differ

from

those

given

on

the

circuit

an

d

layout

diagrams,

when

taken

with

a

Soo11/V

meter.

magnitude

of

the

signal,

two

are

quoted

in

the

diagrams

and

prefixed

by

the

letter

W

for

weak

(100pV)

and

S

for

strong

(lOmV).

VALVE

ELECTRODE

VOLTAGE

ANODE

GRID

2

CATHODE

V2

P

in

3:

94

V5b

5:

138

V6

7:

138

8:

170

V7a

6:

75

7:

17

V7b

1:

No

useful

reading

3:

1.6

Yllb

g:

No

useful

reading

Vi6

(c.r.t.)

10:

103

11:

95

TABLE

2

Voltages

measured

whilst

receiving

a

television

transmission

(including

sound)

and

with

all

the

controls,

excepting

the

one

concerned,

adjusted

as

for

a

normal

picture.

The

fi

gures

in

brackets

were

taken

with

a

SooSZ/V

meter.

VALVE

CONTROL

SETTINGS

ELECTRODE

VOLTAGE

ANODE

GRID

1

GRID

2

CATHODE

V3

(a)

Contrast

minimum

205 205

0

4.8

(4.3)

(b)

Contrast

maximum

194

200

35

(29)

38

V5

(a)

Vision

Int.

Limiter

anti

-clockwise

24

(20)

(b)

Vision

Int.

Limiter

clockwise

146

(140)

Vllb

(a)

Frame

Amp.

anti

-clockwise

5.7

(Nil)

(b)

Frame

Amp.

clockwise

10.5

(Nil)

(a)

Frame

Hold

anti

-clockwise

14

(Nii)

-

25

(Nii)

(b)

Frame

Hold

clockwise

4

(Nil)

-12

(Nii)

V12

(a)

Frame

Lin.

anti

-clockwise

193

204

25

(b)

Frame

Lin.

clockwise

170

194

19

V16

(a)

Brightness

minimum

24

(c.r.t.)

(b)

Brightness

maximum

162

(154)

MODIFICATIONS

All

the

electrical

changes

given

in

this

•out

diagrams

and

the

following

notes

should

sectionare

included

in

the

circuit

and

lay-

be

examined

in

conjunction

with

the

diagrams

10

V310,

V310C,

&

V310D

TELEVISION

RECEIVERS

if

an

unmodified

receiver

is

being

serviced.

These

changes

need

not

be

incorporated

in

an

early

receiver,

unless

experience

indi-

cates

that

it

is

desirable.

Frame

outpnt

valve.

In

some

receivers,

V12

was

a

30P16

Pentode

valve.

It

was

used

at

the

valve

manufacturers

request.

To

accommo-

date

this

valve,

R119

was

1.8Mq,

R129

was

8.2K0,

R156

was

14711,

and

C94 was

rated

at

50V

working.

At

intermediate

stages

R156

had

several

values

(see

"Heater

dropping

resis-

tor"

below).

Some

later

sets

with

30P12

frame

output

valves,

have

8119

as

1.8M(1,

and/or

R129

as

82Kp,

and/or

R156

as

147Il.

Aeater

dropping

resistor

(R

156)•

This

resis-

tor

was

changed

three

times.

For

replacement

purposes

two

values

only

will

be

available,

16011

for

sets

with

a

30P12

frame

output

valve,

and

14711

for

sets

with

a

30P16

(PL82)

frame

output

valve.

The

type

number

of

the

frame

output

valve

should

be

checked

before

ordering

a

replacement

mains

resistor.

Early

sets

with

a

30P16

frame

output

valve

had

a

resistor

(R

155)

in

parallel

with

R156,

moun-

ted

between

pins

4

and

7

on

V14

holder.

This

shunt

resistor

should

be

removed

when

a

re-

placement

mains

resistor

is

fitted.

The

value

of

the

shunt

was

dependent

on

the

value

of

R156,

and

was

as

follows:

R156

R155

16811

1.5KR,20~,1.SW,

Part

No.

26943

15511

2.

2Kf1,

2090,

1.5W,

Part

No.

26975

16011

2.2KR,

20%,

1.5W.

Part

No.26975

Sound

gain.

In

early

receivers,

R90

was

1Kf1

and

C78

was

22PF.

Also,

C75

and

R86

were

not

present,

the

junction

L23/C72

being

connec-

ted

to

chassis.

The

changes

were

made

to

in-

crease

sound

output

and

provide

sound

a.

g.

c.

Hum

on

sound,

V310,

Y310C

only.

In

some

early

receivers,

the

position

of

V9

and

L26

in

the

heater

chain

was

different,

and

R93

was

1M0.

The

changes

were

made

to

reduce

the

possi-

bility

of

hum

on

sound

caused

by

V9.

The

changes

in

the

heater

chain

were

as

follows:

V8

5

was

connected

to

V9

3;

L26

was

connected

to

V1

5,

and

V2

4

was

con-

nected

to

V16

(c.r.t.)

12.

Decoupling

capacitors,

remained

connected

to

the

same

valve

pins.

Coil

cores.

In

early

receivers,

the

coil

cores

were

of

the

standed

slotted

type.

It

is

possible,

with

a

short

trimming

tool,

to

adjust

all

the

cores

without

removing

the

c.

r.

t.

See

also

"Trimming

tool"

on

page

11.

Frame

drift,

V310,

V310C

only.

When

the

W4

rectifier

(MR2)

was

fitted

in

early

sets,

it

was

found

that

the

line

time

-base

was

in-

fluencing

the

frame

time

-base

causing

frame

drift.

C105

was

added

to

minimize

this

effect.

Line

drift.

In

earlier

receivers,

MR2

was

a

Westinghouse

39K2

selenium

rectifier

(coded

BLUE),

C107

was

33PF,

R76

was

g,2K0,

R74

was

27K0,

R134

was

2.2Mf1,

R135

was

3,

gK(1

and

C106

was

connected

to

the

junction

R135/R

142/

screen

winding

on

T3

(t.P.212).

Also,

a

re-

sistor,

R136

(470Kf1)

was

connected

from

the

junction

R138/R140/C106

(t•P.209)

to

the

chassis.

These

components

were

changed

to

reduce

the

possibility

of

line

drift.

How-

ever,

if

the

receiver

is

fully

modified

(this

can

easily

be

verified

by

checking

that

C106,

82PF,

is

not

connected

to

the

lower

tag

on

the

Line

Hold

control,

R142)

and

line

drift

persists,

follow

the

procedure

below:

1.

Disconnect

one

end

of

MR2

and

allow

it

to

cool

for

about

10

minutes.

Then

check

that

its

back

resistance

is

at

least

1M(l

(the

reading

obtained

may

be

misleading

if

the

rectifier

has

not

cooled

down

suf-

ficiently).

Use

a

20,OOOIliV

meter

having

a

15V

internal

battery

on

the

high

resis-

tance

range,

e.g.

Avo

Model

g,

and

connect

the

-ve

lead

to

the

end

coded

RED

on

the

rectifier.

Reconnect

MR2

if

satisfactory.

2.

Replace

V13

with

a

30P4

valve

coded

SE

above

the

word

"Mazda".

The

above

procedure

should

be

followed

each

tiee

V13

has

to

be

changed

to

overcome

line

drift.

The

oscillator

core

driver.

To

overcome

cer-

tain

difficulties

(sticking,

etc.

)

experi-

enced

with

the

spring

loaded

driver

fitted

in

early

receivers

for

adjustment

of

the

oscillator

coil

core,

this

driver

has

been

replaced

in

later

receivers

by

a

Polythene

tube

which

serves

as

a

guide

for

the

inser-

tion

of

a

separate

driver.

A

kit

of

parts

(Part

No.

77515)

with

in-

structions

for

making

this

change

to

an

early

receiver

is

available

from

Murphy

Radio

Ltd,

Service

Department.

The

separate

Driver

(Part

No.77219),

which

is

a

long

plastic

trimming

tool,

has

been

supplied

to

dealers

for

gene-

ral

use

with

these

receivers;

this

tool

is

not

a

part

of

the

equipment

of

each

receiver.

CIRCUIT

ALIGNMENT

General

note.

Avoid

touching

the

coil

cores

and

tuner

unit

trimming

capacitors

unless

there

is

unmistakable

evidence

that

retrim-

ming

is

necessary.

It

is

essential

to

appre-

ciate

that

the

movement

of

a

lead

or

compo-

nent

within

the

tuner

unit

may

seriously

up-

set

the

performance,

particularly

on

Band

III.

■arcing

up.

The

receiver

must

be

allowed

to

warm

up

for

ten

to

fifteen

minutes

before

commencing

alignment.

Control

settings.

All

controls

must

be

set

for

maximum

gain,

i.e.

CONTRAST,

SENSITIVITY

and

VOLUME

clockwise,

VISION

INTERFERENCE

V310,

V310C,

&

V310D

TELEVISION

RECEIVERS

II

LIMITER

anti

-clockwise.

The

STATION

SELECTOR

must

be

set

in

a

B.B.C.

(Band

I)

position

unless

otherwise

stated.

Damping

units.

When

aligning

some

i.f.

and

r.

f.

transformers,

it

is

necessary

to

damp

the

primary

circuit

while

adjusting

the

sec-

ondary,

and

vice

versa,

as

indicated

in

the

Circuit

Alignment

Table

on

page

12.

The

damping

units

are

as

follows;

DAMPING

UNIT

"A":

47011

resistor

in

series

with

a

miniature

1000PF

capacitor.

DAMPING

UNIT

"B":

22011

resistor

with

special

connectors.

A

complete

unit

(Part

No.

69919)

is

supplied

by

Murphy

Radio

Ltd,

Service

De-

partment,

and

it

should

be

modified

as

shown

in

Fig.

4

The

damping

unit

should

be

con-

nected

as

shown

in

Fig.4

and

great

care

must

be

taken

to

avoid

damaging

the

contacts

on

the

tuner

unit

assembly.

If

the

damping

unit

is

placed

across

the

wrong

contacts,

a

valve

an

d

resistor

may

be

seriously

damaged.

Trimming

tool.

To

enable

trimming

adjustments

to

be

made

from

outside

the

chassis,

special

coil

cores

are

fitted.

To

adjust

these

cores,

a

hexagon

headed

trimming

tool

(Part

No.

75191)

is

available

from

Murphy

Radio

Ltd.

,

Service

Department,

price

1/-

at

the

time

of

going

to

press.

On

some

early

sets

standard

type

cores

were

fitted,

see

Modifications

on

p

age

8

.

In

addition,

on

later

receivers,

a

long

plastic

trimming

tool

(Driver,

Part

No.

77219,

already

supplied

to

dealers

for general

use

with

these

receivers)

is

required

for

ad-

justing

the

oscillator

coil

core.

Signal

Oenerator.

Connect

a

signal

generator,

having

an

output

impedance

of

8011,

to

the

points

indicated

in

the

Circuit

Alignment

Table

on

page

12.

Switch

the

modulation

"On"

with

a

depth

of

30

Per

cent,

for

all

adjust-

ments.

Output

meters.

The

following

instruments

will

be

required:

SOUND.

A

3V

a.

c.

meter

in

parallel

with

a

loudspeaker

or

a

3A

dummy

load,

connected

between

the

chassis

and

the

insulated

at

the

bottom

rear

of

the

receiver

chassis.

VISION.

Connect

a

crystal

type

a.c.

meter

between

the

cathode

of

the

c.

r.

t.

(pin

11)

and

chassis.

Use

a

20,

00011/V

meter

(such

as

the

Avo

Model

g,

the

Taylor

Models

ggA

or

77

A,

or

the

Weston

Model

E772

type

5),

a

suitable

rectifier,

and

a

blocking

capacitor,

connected

as

shown

in

Fig.3

The

recommended

types

of

rectifier

are

as

follows:

S.T.

&

C.

type

M1

(Part

No.

58528)

or

type

Q

62

(Part

No.58532)•

Alternatively,

an

oscilloscope

connected

between

the

c.r.t.

cathode

and

chassis

can

be

used.

If

there

is

any

trace

of

instability,

connect

a

lOKll

resistor

at

the

c.r.t.

end

of

the

oscilloscope

lead.

Maximum

output.

Adjust

the

signal

generator

attenuators

so

that

the

receiver

output

does

not

exceed

the

following:

SOUND:

200

mW,

or

0.

8V

across

the

loudspeaker

p.INF

TO

C.R.T.

CATHODE

(PIN

11)

VISION

OUTPUT

INDICATOR

HIGH

STABILITY

Fig.

3.

The

dotted

rectangle

represents

the

multi

-range

meter.

speech

coil

or

3J1

dummy

load.

VISION:

5V

d.c.

at

the

c.

r.

t.

cathode,

as

measured

by

the

indicator

described

above,

or

lOV

peak

-to

peak

on

an

oscilloscope

screen.

Core

positions.

If

two

peaks

are

obtainable

with

the

coil

cores,

the

correct

one

is

that

which

occurs

with

the

core

nearer

to

the

end

of

the

coil

former.

I.f.

re3ectors.

Do

not

increase

the

signal

input

much

over

2

mV

when

finally

aligning

these

circuits;

if

possible,

increase

the

sensitivity

of

the

vision

output

meter.

Tuner

unit.

Before

aligning

the

r.f.

cir-

cuits,

remove

the

screening

covers.

Although

the

Circuit

Alignment

Table

gives

Band

III

frequencies

for

aligning

the

r.f.t.

trimmers

(C16

and

C17)~if

a

signal

generator

capable

of

providing

these

frequencies

is

not

available,

alignment

can

be

carried

out

in

Band

I.

CHANNEL

TUNING

CAPACITORS

C4

C

16/C

17

1

41.5

Mc/s

2

48.25

Mc/s

3

53.25

Mc/s

4

59

Mc/s

5

64

Mc/s

8

188

MC/s

9

193

Mc/s

10

198

Mc/s

12

V310,

V310C,

&

V310D

TELEVISION

RECEIVERS

CIRCUIT

ALIGNMENT

TABLE

OUTPUT

C

O

•.i

U1

.H

p

C

•.~

~

C

O

•.a

U1

+~

>

C

•.i

g

G

O

..~

U]

•.i

>

C

•N

g

'O

q

G

O

U1

K

G

~

b

C.

7

O

VI

k

G

~

G

O

++

UI

.N

>

K

G

~

uotsln

•xeW

uotsln

•xBW

uozstn

•xaW

q

O

•.~

to

•H

7

X

G

~

C

O

.H

PA

M

>

k

G

g

~

b

❑

7

p

W

❑

•.a

~

b

G

O

U7

K

W

.^

e

uotsln

•x8W

C

O

++

to

.ti

~

iC

C

'O

G

a

O

U7

X

G

~

'O

C.

C

O

U1

>C

G

~^

b

C

7

O

UI

k

cti

~

ADJUSTMENTS

AND

REMARKS

1.

Switch

to

Band

I

and

tune

L15

(top

of

can)

2.

Tune

L14

(bottom

of

can)

3.

Tune

L13

4.

Tune

L25

(sec.,

top

of

can)

5.

Tune

L24

(Pri.,

bottom

of

can)

6.

Tune

L23

7.

Tune

L17

(sec.,

top

of

can)

8.

Tune

L16

(Pri.,

bottom

of

can)

9.

Tune

L12

(sec.,

top

of

can)

10.

Tune

L11

(Pri.,

bottom

of

can)

11.

Tune

L8

(Pri.,

bottom

of

can)

12.

Tune

L9

(sec.,

top

of

can)

Repeat

adjustment

8

13.

Tune

C10

(tuner

unit)

14.

Switch

to

Band

III

and

tune

L6

(

osc.

)

15.

Tune

C17

(sec.,

chassis

outerside)

16.

Tune

C16

(Pri.,

chassis

outerside)

17.

Switch

to

Band

I

and

tune

L6

(

osc.)

18.

Tune

C4

(ae.,

chassis

outerside)

Tune

for

mea.

vision

on

Ch.4

and

Ch.5

Re

-tune

L6

(osc.)

accurately

on

local

transmissions

DAMPING

UNIT

CONNECTION

No

damping

No

damping

No

damping

No

damping

No

damping

"A"

to

V4

7

°°A"

to

V5

7

r

c

"'

a

m

"A"

to

V4

2

"A"

to

V3

2

"A"

to

V2

6

m

c

.~

a

No

damping

"B"

across

pri.

`B"

across

sec.

No

damping

No

damping

o

~

'O

~

+'

O

d

i

Z

SIG.GEN.

TO

V3

2

V3

2

V3

2

V3

2

V3

2

Insulated

terminal

Insulated

terminal

'

y

N

C

i-~

~r

Ae.socket

~ M

r-1

~ 8

1 1

~ ~

C

H ~

SIG.

GEN.

SETTING

33.

15

Mc/s

38.15

Mc/s

38.15

Mc/s

38.15

Mc/s

38.15

Mc/s

35.8

Mc/s

36.25

Mc/s

!36.5

Mc/s

38.15

Mc/s

H

See

table

on

page

11

for

Band

III

See

table

on

page

11

for

Band

I

H

H H

~

~ b

'd

Ci

q

G

td

O

~ ~

b

G

C

G

c~

O

m

y

~

CIRCUIT

Adjacent

sound

i.f.

rej.

3rd

own

sound

i.f.

rej.

•„

Sound

take

-off

coil

Final

vision

i.f.t.

Final

vision

i.f.t.

•n

N

i-i

N

f'+

N

C.

G

F

W

4+

2

.~

•N

b

•H

b

C H

d

V1

N

C

G

0

+~

C

7

0 ~

cd

+>

a

m

v;

~

-

+~

m

•H

C

-+

W

4+

C

G

O

~

O

b

G

••+

••~

R

O

Fr

d

+~

b

O

b

+a

+~

q

•.-i

C.

O

G

V1

Vl

7

G

N

U1

~

N

.-+

ti

[~

?

V310,

V310C,

&

V310D

TELEVISION

RECEIVERS

13

a

N

h

Q O

N

e

b ~ ~ h

Fig.

4•

The

coil

positions

and

damping

unit

connections.

14

V310,

V310C,

&

V310D

TELEVISION

RECEIVERS

C

I

2

117

4

6

12

31

3

S

7

10

Wg

81

~0

17

14

jb

ig

IT

22

9

7~S

WI

13

Y

116

~

47

21

C

~

1

2

3

10

4

26

5

41

7

E

9

~

R

2

5

3

Ibl

163

b

160

4

I59

Ib4

26

157

165

23

27

22

156

8

I

M

12

i3

N

~

q~

18

R

MSC

S2~

FI

SI

S~

VlaV

l

b

MRI

Sk

F2

V2

MISC

V3/O

VOLTAGES

S

—STRONG

SIGNALS

W

—WEAK

SIGNALS

C

31,

RI9,

R22,R23,

R26,

R27

ARE

ON

THE

RECEIVER

CHASSIS

C12

=

250pf

CI

70

pi

EARTH

C2

6JOpE

z

ALL

VOLTAGES

MEASURED

WITH

A

MAINS

INPUT

Of

240Vc.c.

SO

C/S

S2a

eta

,

-

mo

o

el

AC/DC

MAINS

~„

526

I9

FI

2A

PlA1N

cu7

OOSyf'

CHANNELS

1,283

ONLY

~~

I

C3

I~

CASCOOE

RF.

~

Vla

~30LI

s

I~

M51

T4TOpf

iz

SENStT

VITV

SEMSITiVITY

E.E.C.

I.T

A.

R164

R163

25n

SJ

19n

230V

M

240V

O

220V

~C,

o21cv

25pV

0

M

200V

zoov

53a

2sov

--o

~2

lov

o

D.C.

zaD

novp

Q23ov

R161

RI60

R139

RI58

RI37

33n

33n 33n

33n

a

y

2,~

a

d

21 O ~D~.

25

o

A.c.

0

2

536

0

D.C.

0

MRI

LW7

CE1

IOOOpi

2oove

D

.

C

.

/

ersov

se

zlove

—

ezaov

220Ve

e230V

0119

T

IOONF

az

RF/

I

rn

TO

GRID

I~PIN

2)

OF

V3\

OI

RIB

to

TO

JUNCTION

C2T/R21

C21

IONF

ez

NOMINAL

=CilB

'

200yF

rm

KT

VI

,~

ea

V8

Qel

V3

©ez

V4

Hs/

V3

C7E

C56,

IOOQi

1000{

'C26

io

C

o

9

ovr

=~000ls

1aoo~

ID~~

1

j,=

..

4

I

V

r

sa

L41

n

59

FREO.CHAMCER

F2

S

OOMA

MAG-NICKEL

23ove

e22ov

2aov

e

ezlov

25

~V

'

A.C.

a

200

V

S

3D

V14

O

V13

~j

ee

CEO

°1

C11

~

2sovr

..

.

COPYRIGHT

SUBJECT

TO

ALTERATKIN

B'ITiIOIR

NOTICE.

ISSUE

O

Fig.

5•

Tuner

unit

and.poxer

supply

circuit

diagrams.

See

page

i6

for

the

main

circuit

diagram.

Also

see

•Voltage

Readings'

on

page

8.

V310,

V31

OC,

&

V31

OD

TELEVISION

RECEIVERS

15

C

R

10

4

Ib

b

17

27

13

22

26

24

Ib

b

17

9

IB

14

11

57

19

21

Z

~4

23

1210

8

18

9

5

17

14

I

8

12

3

b

n

4

9

8

21

654

89

7

b

3

OSC.

CORE

ADJUST-

MENT

-

C

V2

30C1

Ist

I.F.T.

JJ

30L1

C17

~ ~

C16

RI8

tJ

C27

2

J

2

clo

C4

~e

C6—

~

SI

~'

I

OSC.

CORE

STATION

SELECTOR

OSC.

COME

ADJUST—

MENT

Y3/O/YT20

~42

~/I''DIII~411f11!II~'~illlllllllllll~

P.F.T.B

OSCILLATOR

COILS

61l~~

8

d

RS

IS

PRESENT

Ja

r

av

ON

CHANNELS

1,2

AND

3

~.

COILS

ONLY

CHANNEL

DENTIFICATION

COLOUR

R3

//Illlb

IIIIIIIIIPI

AERIAL

CgLS

a

0 0 0 0 0 0

FIXED

CMMS

b

MM

~CONTACTS~

~{

o

n

o

AA

W

~

I1

N

W

U1

W

V'~

O ~

~~

O O

Jt

11

r

2Q

IJ II

O O O O

J

t

~9

y~

v

51

e

INNER

SIDE

OF

SWITCH

WAFER.

Fig.

g.

Details

of

tuner

unit

chassis.

I6

V310,

V31

OC,

&

V31

OD

—;

C

L

R

MSC

37

36

79

41g4

43

42

45

a6

50

49

51

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57

116

2

7

5

71

74

72

32

75

77

~

39

84

82

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86

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54

~

61

24

25

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13

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17

14

1819

20

21

23

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30

21

37

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51

54

52

251

57

58

252

6

63

6

29

86

87

~

3941

28

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91

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9

96~

gg~97

101

99

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104

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71

72

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153

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Vc~V3

V9b

VIOa

V4

VSa

TI

VIOb

Vb

VSb

V7a

v.~io

ST

COMMON

LF.

AMP.

1ST

VISION

I.F.

AMP.

VISION

DET.

VIDEO

AMP.

VI

S.INT.

LIMITER

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r

az

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nY

.

f)

u

2l

TO

L9/RIY

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TUNE

R,UNIT

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R29

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pf

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ro

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1ST

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LF.

AMP.

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I000v~T

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L23

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s

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f

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~

r

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A.F.

AMP.

/d

9

t

RIOI

Y

390n

R102

zzo

Nn

A.

F.

OUTPUT

TI

/sa

b'~

RI04

leon

5

V

IOb

30FL1

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LIMBER.

BR`

LINE6

FRAME

SYNC.

SEP.

R38

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R71

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f

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+

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l~

e

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-

/

T

oz

<6

~

v7a

30FL1

INn

C61

Fig.

7•

The

main

circuit

diagram,

excluding

the

tuner

unit

and

power

supply

sections

which

are

shown

on

page

14•

The

voltage

conditions,

together

with

additional

readings

are

given

on

page

8.

16

V310,

V310C,

&

V310D

TELEVISION

RECEIVERS

17

C

27

74

37

75

71

72

32

7S

77

~

36

~

94

79

82

4144

43

42

83

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50

48

86 85

gg51

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54

~

57

116

bl

107

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~

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qq

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92

108

93~

97

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23

24

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13

12

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20

21

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33

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.,'

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F.

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AMP.

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~~

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q

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s

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F

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VIS.INT.

LIMITER.

BRIGHTNESS

FOCUS.CENTRING

ION

TRAP

LINER

FRANE

SYNC

SEP.

R58

lo.n

Fig.

7.

The

main

circuit

diagram,

excluding

the

tuner

unit

and

power

supply

sections

which

are

shown

on

page

14.

The

voltage

conditions,

together

with

additional

readings

are

given

on

page

g.

laa

'

72

I

R

1/a/

4TOn

~

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30FL1

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FRANE

SYNC.

SEP.

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li

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pn

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FRAME

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FRAME

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FRANE

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FRAME

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COILS

u,?r7s•c

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r

L28

COPIRIGHT

SUBJECT

TO

KTERgT10N

WITHOUT

NOTICE

ISSUE

O

The

frequencies

under

the

oscilloscope

traces

refer

to

the

oscilloscope

time

-base.

Component

terminals

and

connecting

leads

are

identified

by

test

point

(t.

p.)

numbers

which

correspond

with

those

appearing

on

the

chassis

diagrams.

Po

63

-ELE:VISION

RECEIVERS

17

'

U

~

58

~'

64

~

III

ql

92

l08

1

9

106

97

~

94

105

C

24

32

31

33

35

27

38

~

7e

39

ib

~

82n

7R

VIb

ISI

112

149

1

36

113

114

IIb

137

1

119

141

~Il~

253

1~1421~124

12RM75h31

Vlla

MR2

VI3

V

I

4

Vllb

T3

VIST2

V1

147

148

145

R

MKC.

"

R64

~ooxn

.~

71

/1/

/79

C.R.T.

V16

CRM

172

LIN

~~AME

COILS

C3B

PI

R

i

I

wNlllu

ROM

VIS

~\

Tsv

35

</.

ISI

20xn

zz/

R149

INS

/9Q

f-~

06

~_

C99

0~0029i

CIH

~

PSRi

/99

R134

4•TMn

a~

LINE

OUTPUT

EFFIGY

DIODE

p

z2/

-

1

9

clog

I.Sn-~•

O.25NF

OI;

YI4

0191

;'

9

an

V13

30P4

20B

d

MR2

V4

d~

700

b

7/9

RI39

Tow

RI40

aToxn

T3

2/I

C

o

n

INno~

l

O

I

p

1~

I

~

IJ7

1JJ

I

~I;

VIS

U26

zxa

IO)

I//

RI37

I

sxn

un

7/J

E.H.T.

RECT.

227

11~

RI35

iC106

93xn

B2pi

2/7

p

C108

R142

O

Olyi

Ixn

GHTNE55.

FOCUS,CENTRING

ION

TRAP

FRAME

SYNC.

SEP.

1

Ilp,'

R7

10

UNE

NOLD

2.

8256

s.an

UNE

SCAN

COILS

CI05

~

56pi

0

FJIJ.

To

cu.

FNIK

AIIOD!

LINE

UNE

AMPLITUDE

LINEARITY

nz

FRAME

OSC

8124

390n

FRAME

OUTPUT

v¢

1jj

30P12

/e2

Rln

~

man.

R128

Ixn

/

/Aa

FRAME

AMPLITUDE

FRAME

HOLD

FRAME

LINEARTY

FRAME

SCAN

CglS

w~~

`ze

12n

d

li

r"

s9

COFYRIGNT

SUlJECT

TO

AITFPATION

WITHOUT

NOTICF~

IS{UE

O

The

frequencies

under

the

oscilloscope

traces

refer

to

the

oscilloscope

time

-base.

Component

terminals

and

connecting

leads

are

identified

by

test

point

(t.

p.)

numbers

which

correspond

with

those

appearing

on

the

chassis

diagrams.

Murphy Radio V310 User manual

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