Hallicrafters Ht-45 mark ii a Training manual

I

_ffe_._

fa.

_.

hallicratiers

OPERATING

AND

SERVICE

INSTRUCTI

MODEL

HT-45

MARK

II

A

a

/)

be

IONS

INTRODUCTION.

Hallicrafters

Model

HT-45

Mark

IA

RF

Linear

Amplifier

provides

amplification

of

RF

signals

in

the

80-meter

through

10-meter

amateur

bands.

The

amplifier

uses

an

Eimac

Type

3-400Z

Zero

Bias

triode

in

a

grounded-grid

circuit

andis

designed

for

operation

with

any

exciter

having

an

output

impedance

of

50

ohms

and

capable

of

delivering

approximately

45

watts

of

drive.

The

linear

amplifier

incorporates

the

fila-

ment

supply,

a

cooling

blower,

and

control

cir-

cuits.

Switches

on

the

front

panel

provide

control

of

primary

power

to

the

blower

motor,

the

filament

transformer,

and

external

power

supply

filament

voltage

and

power

to

operate

a

plate-voltage

re-

lay

in

the

Mark

IIA

Power

Supply.

The

RF

input

circuit

of

the

linear

amplifier

utilizes

a

wide-band

ferramic

transformer

which

is

broad-band

tuned

and

essentially

flat

from

3.5

to

30

megacycles.

The

transformer

elevates

the

tube

trol

and

power

lines.

filament

in

the

grounded-grid

circuit

and

provides

an

impedance-matching

circuit.

The

input

impe-

dance

is

50

ohms

to

match

the

output

impedance

center

for

most

commercially

available

exciters.

Approximately

45

watts

of

driving

power

is

required

for

1,000

watts

input

to

the

3-400Z

tube.

Figure

1.

Hallicrafters’

Model

HT-45

Mork

HA

RF

Linear

Amplifier.

SECTION

|

GENERAL

DESCRIPTION

By

use

of

the

grounded-grid

circuitry,

more

than

one-half

of

the

driving

power

is

fed

through

to

the

output

and

appears

as

useful

power.

when

required.

The

RF

output

circuit

is

a

Pi-network

with

an

operating

"'Q"

of

12

and

an

output

impedance

design

center

of

50

ohms.

Taps

on

the

coil

are

selected

by

the

BAND

SWITCH

for

the

desired

frequency

and

the

lever

switch

under

the

tuning

control

is

switched

ON

for

the

3.5

to

4.0

megacycle

range.

The

plate

circuit

is

tuned

to

resonance

by

the

TUNING

control.

The

LOADING

control

permits

matching

to

loads

other

than

50

ohms

The

HT-45

Mark

IIA

Linear

Amplifier

is

designed

for

use

with

an

external

power

supply.

The

Model

Mark

IIA,

described

in

Section

IX

of

this

manual,

has

been

designed

specifically

for

use

with

this

amplifier.

When

power

supplies

other

than

the

Mark

IIA

are

used,

careful

atten-

tion

must

be

given

to

the

interconnection

of

con-

The

Model

HT-45

Mark

HA

RF

Linear

Amplifier

and

the

Mark

IIA

Power

Supply

are

manufactured

at

Radio

Industries,

Inc.,

a

sub-

sidiary

of

The

Hallicrafters

Co.,

and

an

outstand-

ing

leader

in

the

design

and

manufacture

of

RF

linear

amplifiers

and

power

equipment.

1-2.

TVI

(TELEVISION

INTERFERENCE

SUPPRESSION).

NOTE

With

any

high

power

installation,

parti-

cularly

in

television

fringe

areas,

TVI

may

be

a

problem.

Should

this

occur,

it

is

recommended

that

a

high-quality,

low-pass

filter

be

used

at

the

output

of

the

linear

amplifier.

Consideration

has

been

given

to

minimizing

possible

local

TVI

problems

in

the

design

of

the

HT-45

Mark

IJA

Linear

Amplifier.

The

unit

is

adequately

shielded

and

bypassed

at

the

RF

fre-

quencies

encountered.

However,

it

is

recom-

mended

that

all

station

equipments

be

bonded

together

with

heavy

copper

wire

or

strap

and

be

connected

to

an

earth

ground.

When

bonding

equip-

ments

together,

care

should

be

exercised

that

high-impedance

grounds

are

not

encountered.

To

prevent

high-impedance

grounds,

avoid

wire

lengths

which

are

equal

to

multiples

of

odd

one-

quarter

wave

lengths

at

your

favorite

operating

frequencies.

1-3.

ADDITIONAL

FEATURES.

The

Model

HT-45

Mark

ITA

Linear

Ampli-

fier

incorporates

many

features

for

reliability

and

ease

of

operation.

All

important

circuits

are

metered

by

a

five-position

switch

and

an

easily-

read,

front-panel

meter.

The

metering

circuit

indicates

grid

current,

plate

current,

RF

output

voltage,

and

DC

plate

voltage.

In

the

RF

OUTPUT

position,

the

plate

TUNING

control

is

adjusted

for

maximum

indication

of

RF

output

voltage.

A

green

lamp

on

the

front

panel

indicates

when

power

is

applied

to

the

filament

and

cooling

blower.

A

red

lamp

on

the

front

panel

indicates

when

plate

power

is

applied.

The

overall

sche-

matic

diagram

of

the

Hallicrafters'

}<odel

FT-45

Mark

DA

RF

Linear

Amplifier

is

shown

in

figure

7.

SECTION

II

SPECIFICATIONS

2-1.

GENERAL,

Specifications

for

the

Model

HT-45

Mark

IA

RF

Linear

Amplifier

are

presented

below.

Mode

of

Operation.

...

2.

-

++

eee

Power

Requirements,

AC

......-+-+e05

Power

Requirements,

DC

.....-..+.++-++5

Input

Impedance

.....--

ee

eee eee

eee

Output

Impedance

....-.

2+

+e

eee

Driving

Power

for

1,000

watts

input.......-

Overall

Dimensions

........-2+-++e205

Net

weight...

2...

eee

ee

es

Grounded-grid,

class-B,

linear

power

amplifier.

155

watts,

115

volts,

60

cycles*.

3,000

volts,

333

milliamperes**.

2,500

volts,

400

milliamperes.

2,000

volts,

400

milliamperes.

50

ohms

(design

center).

50

ohms

(design

center).

45

watts

(approximately).

15

inches

wide

x

13

inches

deep

x

8

inches

high.

Shipping

weight

©...

2.2

ee

eee

*Blower

and

filament

power

only

(see

Power

Supply

Requirements).

**Voltage

obtainable

from

Mark

IIA

Power

Supply.

***Tube

and

chimney

shipped

in

separate

carton,

total

weight.

SECTION

Ill

INSTALLATION

3-1.

UNPACKING.

After

removing

the

amplifier

from

the

car-

ton,

examine

it

for

any

damage

which

may

have

occurred

in

shipment.

Should

any

sign

of

damage

be

apparent,

immediately

file

a

claim

with

the

carrier

stating

the

extent

of

damage.

Check

and

retain

all

shipping

tags

and

cartons

for

special

instructions

and

possible

re-use.

The

Type

3-400Z

tube

and

chimney

are

shipped

ina

Separate

carton

to

reduce

possibility

of

breakage

in

shipment.

NOTE

DO

NOT

REMOVE

TUBE

AND

CHIM-

NEY

FROM

CARTON

UNTIL

READY

TO

INSTALL.

The

tube

is

installed

by

inserting

it

in

the

socket

and

exerting

a

gentle

straight

downward

pressure

on

the

tube.

DO

NOT

FORCE

TUBE

INTO

SOCKET.

Remove

the

top

cover

from

the

amplifier

cabinet

by

turning

the

fasteners

one-quarter

turn

counterclockwise.

Install

the

3-400Z

tube

in

its

socket

and

place

the

glass

chimney

over

the

tube.

The

glass

chimney

is

aligned

and

held

in

place

by

three

clips

on

the

chassis.

Identify

the

plate

lead,

attached

to

top

of

RF

choke

RFC1,

and

attach

it

to

the

heat-radiating

plate

cap

on

the

3-400Z

tube.

(See

figure

5.)

Secure

the

plate

lead,

using

the

brass

screw

in

the

center

of

plate

cap.

DO

NOT

TIGHTEN

SCREW

EXCESSIVELY,

as

high

torque

applied

to

the

plate

cap

cowd

result

in

tube

damage.

Replace

the

top

cover,

noting

the

align-

ment

of

the

tab

which

engages

the

equipment

interlock

switch,

and

secure

it

in

place

by

turning

the

fasteners

one-quarter

turn

clockwise.

3-2.

LOCATION.

It

is

very

important

that

the

amplifier

be

piaced

in

an

operating

position

that

enables

unob-

structed

air

circulation

directly

behind

and

atthe

top

of

the

unit.

The

air

intake

for the

cooling

blower

is

located

at

the

rear

of

cabinet

and

neces-

sitates

exhausting

of

the

warm

air

out

ofthe

top

of

cabinet.

UNDER

NO

CIRCUMSTANCES

SHOULD

ANY

OBJECT

BE

PLACEDON

TOP

OF

CABINET,

PREVENTING

EXHAUST

OF

WARM

AIR.

3-3.

POWER

REQUIREMENTS.

The

Model

HT-45

Mark

TIA

RF

Linear

Amplifier

requires

an

operating

power

of

155

watts

(115

volts,

60

cycles

AC)

for

the

blower

and

filament

circuits

and

a

plate

power

supply

of

3,000

volts

DC

at

350

milliamperes.

Input

connec-

tions

for

the

power

and

control

circuits

are

made

through

a

multiple-conductor,

number-coded

cable.

The

cable

is

designed

to

terminate

at

a

barrier-type

terminal

strip

and

a

high-voltage

type

connector

on

the

Mark

IIA

Power

Supply.

Connections

are

shown

in

figure

2.

In

the

event

another

power

supply

is

used,

careful

attention

must

be

given

to

the

interconnecting

diagram,

figure

2,

and

power

supply

schematic

diagram,

figure

8,

to

insure

proper

connection.

3-4.

INPUT

AND

OUTPUT

CONNECTIONS.

a.

RF

Input.

The

input

connection

for

the

RF

driving

signal

is

located

at

the

rear

of

the

cabinet.

A

chassis-mounted,

female,

phono-type

connector

is

provided

for the

input

connection.

The

mating

connector

is

supplied

with

the

equip-

ment

and

is

used

by

connecting

to

a

short

length

of

RG-58/U

coaxial

cable

terminated

ina

connec-

tor

mating

with

the

exciter

output

connector.

Refer

to

figure

3

for

location

of

the

RF

input

connector

and

cabling

diagram.

NOTE

For

best

performance,

the

input

cable

should

be

less

than

one-quarter

wave-

length

at

the

highest

operating

fre-

quency.

When

the

amplifier

is

used

with

an

exciter

that

will

not

deliver

45

watts

or

more

of

driving

power,

the

ampli-

fier

cannot

be

driven

to

the

rated

1,000

watts

input.

In

certain

cases

it

may

be

desirable

to

reduce

the

output

of

ex-

citers,

having

output

capabilities

in

excess

of

45

watts,

by

insertinga3-DB

attenuating

pad.

For

information

cover-

ing

the

installation

and

construction

of

a

suitable

attenuator,

see

Section

VII,

Supplementary

Data.

b.

RF

Output.

The

output

connection

for

the

RF

output

signal

is

located

at

the

rear

of

the

cabinet.

The

output

connector

is

a

chassis

mounted,

UHF

Type

coaxial

connector

(SO-239)

and

mates

with

a

UHF

Type

coaxial

connector

(PL-259).

The

power

output

developed

requires

the

use

of

RG-8/U

coaxial

antenna

feed

line.

The

linear

amplifier

performs

best

when

the

load

impedance

is

as

near

to

50

ohms

as

is

practical.

A

load

impedance

of

50

ohms

reduces

VSWR

(voltage

standing

wave

ratio)

on

the

transmission

line.

Refer

to

figure

3

for

location

of

the

output

connector

and

interconnecting

data.

-3

ae

errpae

Pe

Ain

atciel

CABLE

+

3,000V

O-C

HIGH

VOLTAGE

WIRE

#12

-

3,000V

D-C

HIGH

VOLTAGE

WIRE

#7

1i5V

A-C

(SWITCHED)

TO

RELAY

KI

WIRE

#3

1i5V

A-C(SWITCHED)

TO

T2

(Fil

Vi-v2}

WIRE

#5

UISV

AC

(SWITCHED)

TO

Te

(FIL

VI-Ve2)

WIRE

#6

H5V

A-C(INPUT

TO

CONTROL

CIRCUITS)

WIRE

#2

CHASSIS

GROUND

WIRE

#8

1I5V

AC

(INPUT

TO

CONTROL

CIRCUITS)

WIRE

#1

S,

GROUND

WIRE

OR

STRAP

BETWEEN

ALL

EQUIPMENTS

115V

A-C,

GOCYCLE

IN

=

EARTH

THIRD

WIRE

TO

POWER

GROUND

SYSTEM

GROUND

SUPPLY

NOTES:

1.

FOR

230V

A-C,

60

CYCLE,

SINGLE

PHASE

GROUNDED

NEUTRAL

OPERATION:

REMOVE

JUMPER

WIRE

BETWEEN

TERMINALS

1

‘AND

8

AND

CONNECT

JUMPER

WIRE

BETWEEN

TERMINALS

|

AND

9

ON

TERMINAL

BOARD

TB2.

CONNECT

INPUT

POWER

TO

TERMINALS

1,8,

AND

9.

TERMINAL

6

MUST

BE

CONNECTED

TO

NEUTRAL

(GROUND)

OF

POWER

LINE.

2

REFER

TO

SCHEMATIC

DIAGRAM

FOR

THE

MARK

ITA

POWER

SUPPLY

AND

CONNECT

TRANSFORMER

Ti

FOR

230V

OPERATION

AT

TERMINAL

BOARD

TBI.

3.

POWER

CORD

AND

TWO

A-C

POWER

PLUGS

ARE

SUPPLIED

WITH

POWER

SUPPLY.

Figure

2.

Interconnecting

Cabling

Diagram,

HT.45

Mark

IIA

Amplifier

and

Mark

IIA

Power

Supply.

TYPICAL

EXCITER

LINEAR

AMPLIFIER

POWER

SUPPLY

REAR

VIEW

ANTENNA

QWIRE

INTERCONNECT

RELAY

WITH

CABLE

IN

THE

EVENT

IDLING

CURRENT

AUX.

CONTACTS

CONTROL

CIRCUIT

1S

NOT

USED

CONNECT

JUMPER

WIRE

ACROSS

TO

AC

POWER

LINE

TERMINALS

OF

TB!

ON

LINEAR

IDLING

CURRENT

AMPLIFIER.

CONTROL

CIRCUIT

T

“Yo

RECEIVER

~

Figure

3.

Suggested

System

Cabling

Diagram,

Linear

Amplifier,

Exciter,

and

Power

Supply.

A

high-grade,

coaxial-type

antenna

change-

over

relay

is

recommended

for

use

in

the

installa-

tion

of

the

linear

amplifier.

When

selecting

the

antenna

changeover

relay,

a

relay

with

auxiliary

contacts

should

be

used

if

the

idling

current

con-

trol

provision

is

to

be

utilized.

The

antenna

relay

is

normally

operated

by

contacts

of

the

VOX

(voice

operated)

relay

in

the

exciter

unit.

Figure

3

illustrates

a

typical

interconnection

of

the

antenna

relay

and

the

wiring

to

auxiliary

contacts

to

pro-

vide

idling

current

control.

3-5.

IDLING

CURRENT

CONTROL

CIRCUIT.

The

type

3-400Z

tube,

a

zero-bias

triode

with

operating

voltages

up

to

3,000

volts

DC,

does

not

require

the

application

of

bias

voltage,

either

for

normal

operation

or

in

the

standby

condition.

However,

in

the

standby

condition

with

no

driving

signal

applied,

the

presence

of

plate

voltage

and

the

heated

filament

permits

an

idling

current

to

flow

through

the

tube.

The

amount

of

idling

current

flowing

in

the

standby

condition

is

controlled

by

the

resistance

of

the

ground-return

circuit

of

the

filament.

Therefore,

the

amount

of

idling

bias

can

be

reduced

by

insertion

of

a

resistance

in

the

ground-return

circuit

during

standby.

The

resis-

tance,

which

is

inserted

during

standby,

must

be

removed

during

the

transmit

condition.

The

two-

connector

terminal

board

(TB1)

at

the

rear

ofthe

cabinet

serves

this

purpose,

see

figure

3.

The

two

leads

terminated

at

TB1

provide

a

low

resistance

path

and

effectively

remove

the

resistor

from

the

circuit

when

auxiliary

contacts

of

the

antenna

relay

close

in

the

transmit

condition

or

when

a

perma-

nent

jumper

is

placed

across

the

two

terminals.

Idling

current

during

standby,

when

the

two

termi-

nals

are

jumpered

together,

is

approximately

120

milliamperes

compared

with

40

milliamperes

when

the

jumper

is

removed.

CAUTION]

THE

RESISTOR

IN

THE

GROUND-

RETURN

CIRCUIT

MUST

BE

JUMP-

ERED

OR

SHORTED

OUT

THROUGH

A

LOW

RESISTANCE

PATH

DURING

TRANSMIT

CONDITION.

FAILURE

TO

OBSERVE

THIS

CAUTION

WILL

RE-

SULT

IN

DESTRUCTION

OF

THE

SERIES

RESISTOR.

Operation

of

the

linear

amplifier

with

idling

current

control

circuit

is

optional

and

entirely

up

to

the

owner's

discretion.

Normal

idling

current

of

approximately

120

milliamperes

is

not

detrimental

to

the

tube

or

circuit

and

pro-

vides

a

bleeder

current

for

the

Mark

IIA

Pr.

2r

Supply.

The

reduced

idling

current

of

appr.xi-

mately

40

milliamperes

still

provides

the

bleeder

current

for

the

Mark

ITA

Power

Supply

but

results

in

reduced

heat

dissipation

of

the

tube

during

standby

condition.

If

the

idling

current

control

circuit

is

not

used,

a

jumper

must

be

installed

permanently

across

the

two

terminals.

If

the

user

elects

to

utilize

the

idling

current

control

circuit,

connec-

tion

to

the

auxiliary

contacts

of

an

antenna

change-

over

relay

and

the

terminal

strip

should

be

made

as

shown

in

figure

3.

The

two

leads

must

be

con-

nected

to

the

auxiliary

relay

contacts

in

sucha

manner

that

when

the

aniema

changeover

relay

is

de-energized

(standb

©ond‘tion),

contacts

are

open,

placing

the

resis

in

.°:€

ground

return

circuit;

when

the

antenna

changeover

relay

is

energized

(transmit

condition),

contacts

close

to

short

the

resistor

out.

SECTION

IV

FUNCTIONS

OF

OPERATING

CONTROLS

4-1.

GENERAL.

Operating

controls

for the

HT-45

Mark

IIA

Linear

Amplifier

and

remote

operation

of

the

Mark

IIA

Power

Supply

are

all

located

on

the

front

panel.

(See

figure

1.)

4-2.

PLATE

VOLTAGE

SWITCH.

The

PLATE

voltage

switch,

a

two

position

(on-off)

toggle

switch,

applies

plate

voltage

to

the

Linear

Amplifier

through

relay

control

circuits

incorporated

in

the

Mark

IIA

Power

Supply

or

other

similar

power

supply.

The

red

lamp

indi-

cates

when

the

plate

switch

is

in

the

ON

position

and

primary

power

is

applied

to

the

plate

trans-

former

in

the

power

supply.

4-3.

FILAMENT

SWITCH.

The

FILAMENT

switch,

a

two-position

(on-

off)

toggle

switch,

applies

power

to

the

filament

and

blower

in

the

amplifier

and

AC

power

to

the

filament

transformer

for

the

rectifier

tubes

in

the

power

supply

when

placed

in

the

ON

position.

The

green

lamp

indicates

when

this

switch

is in

the

ON

position

and

voltage

is

applied.

4-4.

METER

SWITCH.

The

Meter

Switch,

a

five-position

rotary

switch,

selects

the

desired

circuit

to

be

metered.

The

operator

may

select

GRID

MA

(current),

PLATE

MA,

RF

OUTPUT

voltage

or

PLATE

VX10

(voltage).

The

center

position

(not

marked)

removes

the

meter

ir:

the

transmitter

circuitry,

providing

an

OFF

position.

4-5.

BAND

SWITCH

~—

MEGACYCLES.

The

BAND

SWITCH,

a

five-position

rotary

switch,

selects

the

desired

amateur

band,

indi-

cated

in

megacycles.

This

switch

selects

the

pro-

per

taps

on

the

coil

and

additional

tuning

capaci-

tance

for

band

changes.

The

3.5-4.0

MC

ON-OFF

switch,

located

under

the

TUNING

contr.

'.

must

be

in

the

ON

position

for

3.5-4.0

MC

(80meter

band)

operation

only.

This

switch

places

addi-

tional

padder

capacitance

in

the

plate

tuning

circuit.

The

3.5-4.0

MC

ON-OFF

switch

must

be

in

the

OFF

position

for

all

other

operating

fre-

quencies.

4-6.

PLATE

TUNING.

The

plate

TUNING

control,

a

variable

capa-

citor,

».sonates

the

plate

circuit

at

the

desired

frequency.

4-7.

PLATE

LOADING.

The

plate

LOADING

control,

a

variable

capacitor,

adjusts

the

transformer

ratio

of

the

Pi-network

to

reflect

the

desired

load

to

the

tube.

4-8.

METER.

The

meter

provides

an

indicator

for

tuning

the

amplifier.

The

meter

indicates

grid

current

(0

to

500

MA),

plate

current

(0

to

500

MA),

RF

output

voltage

(arbitrary

scale),

and

plate

voltage

(0

to

500

volts

x

10).

Figure

4.

Bottom

View

of

Linear

Amplifier,

Showing

Component

Locations.

SECTION

V

OPERATING=»PROCEDURE

1

te

5-1.

GENERAL.

Operating

procedures

for the

Model

HT-45

Mark

IIA

RF

Linear

Amplifier

are

covered

inthe

following

paragraphs.

Careful

attention

should

be

directed

to

the

tuning

procedure

variations

re-

quired

for

the

mode

of

operation

desired.

During

the

tune-up

procedures,

continuous

reference

should

be

made

to

the

meter

and

operation

should

be

checked

on

the

meter.

A

monitor

oscilloscope,

although

not

required,

is

extremely

useful

in

tuning

a

linear

amplifier

for

all

modes

of

opera-

tion.

Refer

to

the

latest

ARRL

Handbook

for

detailed

instructions

covering

the

use

of

a

moni-

tor

oscilloscope.

The

oscilloscope

permits

accur-

GLass

~~

CHIMNEY

qetoenep

>

ZS

in

ate

determination

of

output

power

in

any

mode.

The

metering

circuit

will

establish

the

DC

input

power

during

tune-up

procedures

and

the

average

power

when

transmitting

in

the

single

sideband

(SSB)

or

AM

(amplitude

modulated)

voice

modes.

There

are

many

factors

which

influence

the

ability

of

a

meter

to

indicate

the

power

input

in

voice

modes

of

operation.

Some

of

these

are

the

degree

of

damping

in

the

meter,

individual

voice

characteristics,

microphone

frequency

response,

exciter

audio

bandwidth,

ete.

A

typical

meter

reading

in

normal

SSB

operation

will

be

approxi-

mately

175

milliamperes

on

voice

peaks

when

the

switch

is

set

to

the

PLATE

MA

(current)

posi-

tion.

teeya

|

Ss

iin,

$3

(INTERLOCK)

Figure

5.

Top

View

of

Linear

Amplifier,

Showing

Component

Locations.

5-2.

PRELIMINARY

PROCEDURES.

Before

operation

or

tune-up

is

attempted,

the

following

must

be

checked

and

completed:

1.

All

power

connections

andcontrol

lines

to

the

external

power

supply

must

be

made

in

accordance

with

information

contained

in

Section

Mil.

2.

All

station

equipments

should

be

bonded

together

and

connected

to

an

earth

ground.

3.

The

output

of

the

linear

amplifier

must

be

connected

to

a

50-ohm

antenna

load

or

toa

dummy

load

capable

of

dissipating

the

output

power.

Connection

to

the

antenna

should

be

made

using

Type

RG-8/U

coaxial

cable.

DO

NOT

ATTEMPT

TO

OPERATE

ORTUNE

THE

LINEAR

AMPLIFIER

WITHOUT

A

SUITABLE

LOAD

CON-

NECTED

TO

THE

OUTPUT.

4.

A

source

of

RF

driving

power

must

be

connected

to

the

RF

input

connector

through

a

length

of

coaxial

cable.

5.

The

antenna

changeover

relay

should

be

in

the

antenna

transmission

line

and

the

idling

current

control

circuits

should

be

connected

to

the

changeover

relay

or

be

shorted

out

perma-

nently

by

a

jumper,

as

covered

in

Section

III.

6.

The

FILament

and

PLATE

switches

must

be

in

the

OFF

position.

The

topcover

of

the

amplifier

must

be

in

place

and

secured

to

com-

plete

the

interlock

circuit.

7.

The

power

«

nnection

to

the

power

supply

should

be

connec’

:d

to

the

AC

power

line.

CAUTION

Never

connect

equipment

to

the

AC

power

line

with

the

power

switches

in

the

ON

position.

°

5-3.

TUNING.

Tuning

of

the

linear

amplifier

necessitates

observing

the

relative

output

at

a

meter

or

other

indicating

device.

This

is

characteristic

of

all

linear

amplifiers

because

they

do

not

exhibit

as

pronounced

a

dip

at

resonance

asaclass

C

ampli-

fier.

The

power

input

at

resonance

is

dependent

upon

the

RF

driving

power

applied

and

upon

the

loading.

After

the

linear

amplifier

is

properly

resonated

and

loaded,

output

power

may

be

reduced

by

decreasing

the

exciter

output.

8-

NOTE

When

tuning

the

HT-45

Mark

ITA

RF

Linear

Amplifier,

it

is

important

that

the

plate

TUNING

and

LOADING

con-

trols

be

preset

to

the

panel

markings

of

the

controls

for

the

frequency

of

operation

desired.

Subsequent

adjust-

ments

are

made

with

the

TUNING

con-

trol

set

for

maximum

RF

power

as

indicated

by

the

meter

with

meter

switch

set

to

the

OUTPUT

position.

The

plate

LOADING

control

is

adjusted

for

proper

loading

in

accordance

with

Table

I.

TABLE

I

OPTIMUM

VOLTAGE

AND

CURRENT

RATIOS

Plate

Voltage

Plate

Current

|

Grid

Current

PLATE

VX10

|

PLATE

MA_

|

GRID

MA

5-4.

PROCEDURE.

The

following

steps

apply

to

all

modes

of

operation

and

should

be

completed

before

tune-up

for

a

specific

mode

is

attempted:

1.

Place

the

FIlLament

switch

in

the

ON

position

to

apply

voltage

to

the

blower

and

fila-

ment

circuits

of

the

linear

amplifier

and

to

the

power

supply

rectifier

filament

transformer

when

using

the

Mark

IIA

Power

Supply.

The

green

lamp

indicates

applicatior.

=f

power

to

the

above

circuits.

NOTE

Allow

a

minimum

of

four

minutes

for

filament

warmup

before

applying

plate

voltage.

When

using

the

Mark

IIA

Power

Supply,

the

delay

permits

the

mercury

vapor

rectifier

tubes

to

reach

proper

operating

temperature.

If

a

prolonged

period

of

time

has

elapsed

between

operation,

a

fifteen-minute

delay

may

be

desirable

upon

initial

starting

of

the

equipment

to

permit

mercury

vapor

tubes

to

reach

proper

operating

temp-

erature.

2.

Set the

BAND

SWITCH

to

the

desired

frequency

range,

and

the

TUNING

and

LOADING

controls

to

the

center

of

the

corresponding

fre-

quency

on

the

front

panel

markings.

These

mark-

ings

are

approximate

and

serve

as

a

Starting

point

in

tuning.

Do

mes

TABLE

II

AM

MODE

PLATE

VOLTAGE

AND

PLATE

CURRENT

RATIO

Plate

Voltage

Plate

Current

PLATE

VX10

PLATE

MA

*

300

200

250

240

200

300

NOTE

The

3.5-4.0

MC

ON-OFF

switch,

lo-

cated

under

the

TUNING

control,

must

be

in

the

OFF

position

for

all

fre-

quencies

other

than

3.5-4.0

MC

(80-

meter

band)

operation.

3.

Set

the

meter

switch

to

PLATE

MA.

4.

Check

that

the

RF

output

control

on

the

exciter

is

in

the

OFF

position;

no

RF

driving

power

applied

to

the

input.

5.

Place

the

PLATE

voltage

switch

in

the

ON

position.

6.

Observe

the

meter

for

indication

of

idling

current,

(meter

switch

in

PLATE

MA

posi-

tion).

When

utilizing

the

idling

current

control

circuit

to

reduce

idling

current,

the

auxiliary

contacts

on

antenna

changeover

should

be

open

(de-energized)

and

the

idling

current

as

indicated

by

meter

will

be

approximately

40

milliamperes.

If

the

idling

current

control

circuit

is

not

used,

a

permanent

jumper

wire

must

be

inplaceacross

the

two

screw

terminals

on

the

rear

of

the

cabinet

and

the

meter

will

indicate

approxi-

mately

120

milliamperes

of

idling

current,

7.

Set

the

meter

switch

to

PLATE

VX10

position

and

note

indication

on

meter

(paragraph

5-5

and

Tables

I

and

II).

5-5.

CW

OPERATION.

1.

Apply

the

filament

and

plate

voltages

by

completing

steps

1

through

7

of

paragraph

5-4,

set

the

meter

to

PLATE

MA,

andincrease

the

RF

output

of

the

exciter

in

the

CW

mode

(continuous

carrier)

until

the

meter

on

the

linear

amplifier

indicates

approximately

200

milliamperes.

2.

Set

the

meter

switch

to

the

OUTPUT

position

and

adjust

the

plate

TUNING

control

for

resonance

(upward

deflection

of

the

meter).

3.

Increase

excitation

(check

resonance

each

time

the

drive

is

changed)

until

either

the

plate

or

grid

current

shown

in

Table

lis

reached.

4.

Set

the

meter

switch

to

GRID

MA

posi-

“tion

and

observe

the

grid

current

for

comparison

with

Table

I.

5.

In

the

event

the

plate

current

is

less

than

listed

for

the

corresponding

grid

current

ob-

tained

during

tuning,

the

amplifier

is

not

loaded

to

its

optimum

condition.

Increase

loading

by

rotating

the

plate

LOADING

control

counterclock-

wise

in

small

increments.

It

may

be

necessary

to

increase

the

exciter

output

to

obtain

optimum

conditions.

If

the

plate

current

is

more

than

listed

‘yf@im

the

corresponding

grid

current,

the

amplifier

is

loaded

too

heavy.

Decrease

loading

by

rotating

the

plate

LOADING

control

clockwise

in

small

increments.

It

may

be

necessary

to

reduce

the

exciter

output

to

obtain

optimum

conditions.

6.

Repeat

steps

3

through

5

alternately,

gradually

increasing

the

exciter

output

in

incre-

ments

until

the

optimum

conditions,

specified

in

Table

I,

are

reached

for

the

plate

operating

voltage.

5-6.

SSB

OPERATION.

1.

Follow

steps

1

through

7

of

paragraph

5-4

and

steps

1

through

6

of

paragraph

5-5.

2.

Set

the

meter

switch

to

the

PLATE

MA

position.

©

3.

Switch

the

exciter

to

the

SSB

position

and

adjust

the

audio

gain

control

until

the

linear

amplifier

plate

current

peaks

at

170

to

200

milli-

amperes

while

speaking

in

a

normal

tone

of

voice.

CAUTION

Do

not

apply

excitation

to

the

linear

amplifier

without

plate

voltage

applied

to

the

3-400Z.

3-7,

AM

OPERATION.

1.

Follow

and

complete

steps

1

through

7

of

paragraph

5-4

and

steps

1

through

6

in

para-

graph

5-5.

2.

Set

the

meter

switch

to

the

PLATE

MA

position.

3.

Switch

the

exciter

to

the

AM

(DSB)

position

and

adjust

the

exciter

output

until

the

plate

current

meter

indicates

the

plate

voltage

and

current

ratio

shown

in

Table

II.

5-8.

VOICE

OPERATED

BREAK-IN

(VOX).

When

the

exciter

utilizes

voice

operated

break-in

(VOX)

the

PLATE

switch

is

left

in

the

ON

position.

The

antenna

relay

is

actuated

by

the

VOX

relay

to

transfer

the

antenna

and

close

the

auxiliary

contacts

on

the

antenna

relay.

5-9.

CALCULATING

POWER

INPUT.

To

determine

the

average

DC

plate

power

input,

multiply

the

plate

current

by

the

voltage

indicated

on

the

meter

in

the

PLATE

VX10

position

(333

MA

x

300

x

10

=

999

watts).

Meter

readings

will

be

accurate

oniy

when

a

steady

CW

input

is

being

measured.

As

pre-

viously

mentioned,

many

factors

influence

the

indicated

plate

current

on

SSB.

SECTION

VI

SERVICE

DATA

WARNING

HIGH

VOLTAGE

PRESENT

DC

voltages

in

excess

of

3,000

volts

are

present

in

the

linear

amplifier

and

power

supply.

DO

NOT

attempt

to

measure

voltages

with

hand-heldtest

leads

or

to

service

this

amplifier

with

the

high

voltage

supply

on.

In

addition

to

the

danger

of

serious

injury

or

death

from

the

high

voltage

supply,

serious

radio

frequency

burns

can

result

from

coming

in

contact

with

or

in

close

proximity

to

the

plate

and

output

cir-

cuits.

6-1.

CLEANING.

Equipment

utilizing

forced-air

cooling

will

coilect

dust

within

the

unit,

depending

on

the

dust

content

of

the

circulated

air.

All

components

should

be

kept

clean,

as

any

accumulation

of

dust

in

the

high

voltage

or

RF

areas

may

cause

arcing

and

consequent

damage.

CAUTION

When

cleaning

the

variable

capacitors,

use

care

so

as

not

to

nick

or

bend

capacitor

,

‘ates.

Never

use

solvents

for

cleaning

any

°omponent

or

area

of

the

unit.

To.

pre:

2d

method

of

cleaning

is

the

use

of

a

‘acuum

cleaner

while

dusting

with

a

ciean,

flexible-bristle

brush.

6-2.

LUBRICATION.

Lubricate

the

blower

every

six

months

with

a

few

drops

of

SAE

No.

10

oil

at

the

front

and

rear

oil

retainers.

Do

not

over

lubricate.

10-

6-3.

OPERATING

AND

SERVICE

QUESTIONS.

For

further

information

regarding

opera-

tion

or

servicing

of

this

equipment,

contact

the

dealer

from

whom

the

unit

was

purchased.

The

Hallicrafters

Company

maintains

an

extensive

system

of

Authorized

Service

Centers

where

any

required

service

will

be

performed

promptly

and

etficiently

at

no.

charge

if

this

equipment

is

deiivered

to

the

service

center

within

90

days

from

date

of

purchase

by

the

original

buyer

and

the

defect

falls

within

the

terms

of

the

warranty.

It

is

necessary

to

present

the

Bill-of-Sale

inorder

to

establish

warranty

status.

After

the

expiration

of

the

warranty,

repairs

will

be

made

fora

nomi-

nal

charge.

All

Hallicrafters

Authorized

Service

Centers

display

the

sign

shown

below.

For

the

location

of

the

one

nearest

you,

consult

your

dealer

or

your

local

telephone

directory.

Make

no

service

shipments

to

the

factory

unless

instructed

to

do

so

by

letter,as

The

Halli-

crafters

Company

will

not

accept

responsibility

for

unauthorized

shipments.

The

Hallicrafters

Company

reserves

the

privilege

of

making

revisions

in

current

produc-

tion

of

equipment

and

assumes

no

obligation

to

incorporate

such

revisions

in

earlier

models,

i

Authorized

Vp

hallicratters

Service

Center

Communications

Equipment

SECTION

VII

SUPPLEMENTARY

DATA

7-1.

NEUTRALIZATION.

Neutralization

of

the

triode

stage

is

not

necessary.

Grounded-grid

operation,

low-impe-

dance

input,

and

excellent

shielding

and

bypassing

assure

complete

stability

at

all

times.

7-2.

GRID

CURRENT.

Grid

current

will

be

approximately

0

to

75

milliamperes

on

SSB

voice

peaks.

Under

no

cir-

cumstances

should

the

grid

current

be

allowed

to

exceed

200

milliamperes.

NOTE

Excitation

should

always

be

removed

from

the

amplifier

before

the

PLATE

voltage

switch

is

placed

in

the

OFF

position.

7-3.

RF

OUTPUT

VOLTMETER.

The

RF

output

voltmeter

is

connected

across

the

RF

output

connector

and

indicates

output

vol-

tage.

This

meter

is

not

calibrated

to

read

actual

power

but

is

merely

a

tuning

indicator.

Always

tune

for

maximum

voltage

reading

for

a

given

plate

current

withproper

grid

current.

As

this

is

NOTES:

-

RESISTORS

RI,

R2,

AND

R3

ARE

MADE

BY

PARALLELING

2

WATT

CARBON

RESISTORS

Ri«

Oty

13

-

120

OHM

2

WATT

RESISTORS,

R2=

Qty

9-82

OHM

2

WATT

RESISTORS,

R3«

Qty

16

~

2,200

OHM

2

WATT

RESISTORS.

.

SUGGESTED

CONSTRUCTION

USES

AN

LMB

OR

Mit’-BOx,

2:

1/4"X

2-1/4"K

§"

LG.

BOTTOM

RESISTOR

R3

MUST

BE

RETURNED

TO

CASE

GROUND

OR

SHIELD

BASE

OF

INPUT

AND

OUTPUT

CONNECTORS.

not

a

peak

reading

voltmeter,

voice

peaks

will

deflect

the

meter

approximately

one-third

of

the

equivalent

CW

output.

7-4.

CONSTRUCTION

AND

USE

OF

AN

INPUT

ATTENUATOR

PAD.

If

the

exciter

used

to

drive

the

HT-45

Mark

IIA

RF

Linear

Amplifier

has

an

output

of

100

watts,

the

use

of

a

50-chm

3-DB

attenuator

pad

between

the

output

of

the

exciter

and

the

input

of

the

linear

amplifier

will

simplify

ne

tune-up

and

operation

of

both

equipments.

Construction

details

and

the

input

and

output

connections

of

a

suitable

50-ohm

3-DBattenuator

pad

are

given

in

figure

6.

Care

shouldbe

‘2k=>

in

construction,

if

other

values

are

used

to

opin

the

required

resistances,

that

the

power

ratings

of

selected

resistors

are

not

exceeded.

7-5.

TUBE

COOLING.

A

fifty

cubic

foot

per

minute

blower

pressur-

izes

the

bottom

of

the

chassis.

The

air

flow

is

directed

around

the

3-400Z

tube,

through

the

chim-

ney,

and

out

through

the

top

of

the

unit.

Never

operate

the

amplifier

with

the

blower

inoperative,

or

with

the

chimney

removed.

Figure

6.

Suggested

50-Ohm

3-DB

Attenuator

Pad.

“i

QND

SiSSVHO-e

NI

OV

AGII-E

N

OV

AGII-e

“Wa

(G3HOLIMS)

LNO

Jv

ASHI-S

“Ma

(CAHOLIMS)

100

dv

Agii-g

(QARDLIMS)

LNO

dv

ASIF

€

(Q]HSLIMS)

LAO

oy

AGHI-b

NO)

-

SNA

39NVLID¥a'

3OVLIOA

HOIH

'E3N

(-)-g

———___.

(NO)

ee

Buy

S3NIVA

S9NyLIDWd79

‘H¥3Y

WOH

Bo

OaM3IA

S3HOLIMS

AW

108

=

“SA

'S3.LON

w

S2t

Palen

vio

“819

=

w

f

cr

wl

Les

GO

NL

G

ae

Ss

ere

ae

axa

T

=

4

xe,

!

|

id

pone

[vw

mele

=

G9

——

pa

Se

soo

=

indi

AGOGE

-

COGe4

Ss

BOVITOA

HOH

:

id

1

i]

=

aa

A

02

ial

$3

1\VOSW

=

-

=

69

9

yw

gz

HOLIMSONYG

|

7

e244

7

>]

ae

Ae

bs

AXS

|

pee

,

1009

i101

bi

Oee

st

100

—{O7L

$5

c

rai

¢

eo

ae

ONIN]

jag

s

(SNigvet

'

HGEE]

\q

[NC

SW

e-

on

430

ye

eo

7

AMSIT

Oy,

bi]

100

0051-08

7°

;

100

pxe]

MMA

IAAA,

SIH

(Sd

4

at

(inaihe

21

if

ee

0

~

(SQOHLIW

es

ats

gto

use

Mib

a

AA

BE

2ly

+

WOOTUBANI

ses

2

HIS-3N

fo

|

Givg

pe

;

ane

i

a

gtoe

Sivid

'

=

4

aE

i

maetee:

—+t

va

Q31S399NS

HO

~¥NNVW

NI

1x31

01

43434)

“LN3uUND

ONINGI

$39Nd3u

ABONWIS

INNO

TWAOWIY

“BTOAD

TINSNVEL

ONINTG

doy

5d

NI3a

ISAW

1a.

Quvoa

TWNINMSL

LY

34uIM

W3dAne

“‘ATdadhS

YaMOd

“OV

LY

JLYNIWNSL

SHONOMFL!

Sav37

Favd

“O31d(99dS

ASIMYIHIO

S$34

“NT

Live

ef)

Su

SONI

LOY

Y3MOd

‘OOO'l=%

'SHHO

‘A3is19ads

3S!

MY3H.0

SSI“NT

‘MOJA

005

3Hv

SONILYN

3DVLI0A

ONY

'SQVHVdOUDIN

(5A)

NI

uy

S3NIWA

NOLSIS3u

~

Figure

7.

Schematic

Diagram,

Model

HT-45

Mark

ITA

RF

Lineor

Amplifier.

12.

SECTION

VIII

PARTS

LIST

8-1.

GENERAL.

In

the

event

repair

or

replacement

parts

are

required

for

the

Mode!

HT-45

Mark

IIARF

Linear

Amplifier,

refer

to

the

schematic

diagram,

figure

7,

and

the

parts

list

to

determine

the

exact

rc-

placement.

Parts

orders

must

provide

the

follow-

ing

information:

Model

(HT-45

Mark

IIA);

Refer-

ence

Designation

(e.g.

R1);

Description

(e.g.

RE-

SISTOR,

Fixed,

comp,

100K

ohms,

1W,

10%);

Part

Number;

and

Serial

Number.

PARTS

LIST,

LINEAR

AMPLIFIER

Schematic

Hallicrafters

Symbol

Description

Part

Number

CAPACITORS

C1,2

0.005

yw

F,

20%

500V,

Mica

120-001454

C3

0.001

uF,

500V,

Ceramic

120-001455

C4

Variable,

TUNING,

16

to

120-001456

101

PF,

4500V

C5

100

PF,

5000V,

Ceramic

120-001457

C6

0.001

uF,

5000V,

Ceramic

120-001458

C7

Variable,

LOADING,

30

to

120-001459

1000

PF,

1500V

C8

5.0

PF,

20%,

500V,

Mica

120-001460

c9

270

PF,

20%,

500V,

Mica

120-001461

C10

2200

PF,

20%,6000V,Ceramic

120-001462

C11,12

0.0054

F20%,300V,Ceramic

120-001463

C13

0.01

uF,

300V,

Ceramic

120-001464

*RESISTORS

Ri,11_

0.25

Ohm,

1%

1

watt,

120-001480

wire

wound

R2

150

Ohm,

5%,

5

watt,

120-001481

wire

wound

R3,4,

1

Megotim,

2

watt

120-001482

5,6,7

R8

100K

Ohm,

1

watt

120-001483

R9

-

4700

Ohm,

5%

12-:-001484

R10

1500

Ohm,

10%

120-001485

*All

RESISTORS

are

10%,

1/2

watt

carbon

type

unless

otherwise

stated.

COILS

AND

TRANSFORMERS

L1

Coil,

RF

120-001471

L2

Coil,

RF

120-001472

PS1

Suppressor,

Parasitic

120-001474

RFC1

Choke,

RF

120-001477

Schematic

Hallicrafters

Symbol

Description

Part

Number

COILS

AND

TRANSFORMERS

(CONT)

RFC2

Choke,

RF,

2.5

MH

120-001478

RFC3

Choke,

RF

120-001479

Tl

Transformer,

Power

120-001494

T2

Transformer,

RF

Input

120-001495

SWITCHES

$1,2

Toggle,

DPST

120-001486

$3

Interlock,

Push

type

120-001487

S4

Rotary,

Ceramic

120-001488

$5

Rotary,

Nylon

120-001489

S6

Special,

three

part,

A

120-001490

lever

type

mechanical

B

120-001491

linkage

C

120-001492

MISCELLANEOUS

Bl

Blower,

Centrifugal

120-001453

Chimney,

Tube

Pyrex

120-001500

J1

Connector,

Phono

Type

120-001469

J2

Connector,

Coaxial

Type

120-001470

D1

Diode,

Germanium,

1N34A

120-001465

Fi

Fuse,

Cartridge,

120-001

466

3

ampere,

3AG

XF1

Fuse

Holder

120-001451

XI1

Indicator,

w/green

jewel

120-001497

X12

Indicator,

w/red

jewel

120-001498

Il

Lamp,

Incandescent,

120-001467

Type

47

12

Lamp,

Neon,

Type

NE-51H

120-001468

M1

Meter,

0to

1

MA

120-001473

Pi

Plug,

Phono

Type

120-001475

P2

Plug,

Single

Pin,

Red

120-001476

XV1

Socket,

Electron

Tube

120-001499

TBl

Terminal

Board,

Two-Screw

120-001493

vi

Tube,

Electron,

Type

3-400Z

120-001496

-13

(A0€2)

7al

LINDYID

ONIHOLIMS

WOES

WaAITNY

BWENII——

nog

“9-W

ASHI

(ao¢z)

UBISIIGNY

WY

BNI

39VLN0A

HOIH

9-a

A000's-

=

————

ial

;

Twainan

o3aNNoNS

eee

—

a

dae

ENNI-7U09

'9-¥

AOKZ

|

OND

GNNOWD

SISSWHD

=

HOLIMS

LINJAY

3

ALINDYID

ONIHOLIMS

WOUS

“NOL.We3dO

W314i

dN

YVaNI

——

LAdNi-

09

‘D-¥

ASI!

o-v

AD€2

yOd

dNY

@

3

ISMW

ta

3SNa

“G3LAIdWOS

36

LSNW

SNIIM

BIVNMSLW

CaxIS30

SI

NOLVHad0

9-0

AGEZ

NAHM

'NOILVYSdO

9-¥

AGI!

BOd

G3uIM

NIAOHS

3NV

Zl

ONY

I€lt

SCUVOG

TVNINHSL

‘SalLON

NOILOINNOD

ON

=

Yaiaiewy

wan

SLINDUID

WRIA

OL

1

ANd

LNO-

09

‘D-v

AGH

HOLIMS

3iN1d

SLINDHID

ONIHOLIMS

WOud

UBAAIIGANY

BYENIT

——LNdNi-

O9

‘OV

ASIT

+

WALIIGNY

BVENIVSEVLIOA

HOIH

9-0

AOOC'E

—

—_———_—_—_—

‘

a

ONNOWS

W31LSA5

WEMCd

AUVEIed

——-e

YY

3BMOd

OL

JHIM

OYIHL

ANdNi-V

03

°D-¥

GNNOYS

SISSVHD

yao8

2a

HOLIMS

LNSAV

TS

JLINDHID

ONIHSLIMS

WOHS

431914094

YIN

YVENIT”

——aNani-v

09

“O-0

AGIE

NOILOSNNOD

ON

walagy

BYaNIT<——SHINSUIO

BASIAWY

OL

;

nN

1A

=)

IP

ANd

LNO-"09

‘O-7

AGH

m

“

sae

err

ects

ep

A

AR

A

Figure

8

Schemotic

Diagram,

Model

Mark

ITA

Power

Supply.

14.

SECTION

IX

MODEL

MARK

IIA

POWER

SUPPLY

9-1.

SPECIFICATIONS.

Type

of

Circuit.........

Full-wave

center

tapped

rectifier

circuit.

Power

Requirements,

AC...1200

watts,

115

volts

or

230

volt

60

cycles.*

Power

Output

..........-

3,000

volts

DC

at

350

milliamperes.

Overall

Dimensions......

14

inches

wide

x10

inches

high

x

12

inches

deep.

Net

Weight

.......-:.-.-.

58

pounds.

Shipping

Weight.........

75

pounds.

**

*

Input

circuit

may

be

connected

for

either

115

volt

AC,

60

cycle

or

230

volt

AC,

60

cycle,

grounded

neutrai

operation.

**Shipping

weight

is

total

for

both

cartons;

cover

is

shipped

in

separate

fiberboard

carton.

9-2.

MARK

IIA

POWER

SUPPLY.

The

Hallicrafters'

Mark

IIA

Power

Supply,

shown

in

figures

8

and

9,

is

designed

as

a

com-

panion

unit

for

the

HT-45

Mark

ITA

RF

Linear

Power

Amplifier.

The

power

supply

is

sold

as

an

accessory

item

to

permit

the

purchaser

of

a

Hallicrafters'

HT-45

Mark

IIA

RF

Linear

Ampli-

fier

to

choose

either

a

matching

power

supply

or

utilize

a

home

constructed

supply,

capable

of

delivering

the

required

current

and

voltage.

¢

WARNING

High

voltages

are

present

at

all

points

in

the

power

Supply.

Observe

all

safety

procedures

afforded

to

high-voltage

components.

Before

touching

any

ter-

minals

in

the

supply,

check

the

input

power

for

proper

disconnection

and

dis-

charge

the

filter

capacitor

with

a

wooden

stick

having

a

metal

extension

capable

of

shorting

the

filter

to

ground.

The

Mark

ITA

Power

Supply

is

designed

for

remote

operation

from

controls

located

on

the

front

panel

of

the

linear

amplifier.

The

power

and

control

lines

are

terminated

at

a

ten-connector

barrier-type

terminal

strip

for

ease

of

connec-

tion.

The

primary

input

power

is

terminated

at

these

terminals

and

is

routed

to

and

through

control

circuits

in

the

linear

amplifier.

The

over-

all

schematic

diagram

of

the

Model

Mark

IIA

Power

Supply

is

shown

in

figure

8.

The

power

supply

utilizes,

two

type

866A,

mercury

vapor

rectifiers

in

a

full-wave,

center-

tapped

circuit.

The

rectified

output

is

smoothed

and

filtered

by

a

wide-range

swinging

choke

anda

large

value

of

filter

capacitance.

This

configura-

tion

provides

the

static

and

dynamic

reguiation

characteristic

necessary.

Application

of

primary

power

to

the

power

supply

is

controlled

by

two

switches

on

the

linear

amplifier

and

a

controlled

relay

in

the

power

supply.

Connections

to

the

Mark

ITA

Power

Supply

are

shown

in

figures

2

and

8,

the

interconnection

diagram

and

the

overall

schematic

diagram

respectively.

In

the

event

an

existing

supply

or

home

constructed

Supply

is

used,

careful

attention

must

be

given

to

the

interconnection

of

control

and

power

lines.

The

Mark

IIA

Power

Supply

may

be

shipped

from

the

factory

connected

either

for

115

volt

AC

or

230

volt

AC,

60

cycle,

single-phase,

neutral-ground

operation.

In

either

event,

con-

nections

for

desired

input

source

may

be

made

by

referring

to

figures

2

and

8

and

making

the

alternate

connections

at

terminal

boards

TB1

and

TB2

of

the

Power

Supply.

9-3.

MARK

IIA

POWER

SUPPLY,

PARTS

LIST.

In

the

event

repair

or

replacement

parts

are

required

for the

Mark

IIA

Power

Supply,

refer

to

the

schematic

diagram,

figure

8,

and

the

parts

list

to

determine

the

exact

replacements.

In

the

event

replacement

parts

are

required

and

re-

quests

are

directed

to

the

factory,

the

following

information

must

be

furnished.

Model

(Mark

IIA,

Power

Supply);

Serial

Number;

Reference

Designation

(e.g.

R1)

Descrip-

tion

(e.g.

RESISTOR,

Fixed,

wire

wound,

100K

ohms,

50W,

etc.);

and

Part

Number.

+15

PARTS

LIST,

POWER

SUPPLY

Schematic

Hallicrafters

Symbol

Description

Part

Number

Ci

Capacitor,

8

uF,

3000V,

Oil-

Filled

Paper

120-001502

LI

Choke,

Power,

Swinging

4

to

16

H

120-001508

J1

Connector,

Single

Pin,

Red

120-001476

El

Cord,

Power,

Three-Conductor

120-001503

Fl

Fuse,

Cartridge,

8

ampere,

3AG

120-001504

Fl

Fuse,

Cartridge,

15

ampere,

3AG

(alternate)

120-001505

XFl

Fuse

Holder

120-001451

11

Lamp,

Neon,

Type

NE-51

120-001506

Pl

Plug,

3-wire

AC

(115

Volt)

120-001509

Pl

Plug,

3-wire

AC

(230

Volt)

120-001510

R1,2

Resistor,

100K

Ohm,

5%,

50

watt,

wire

wound

120-001445

R3

Resistor,

10K

Ohm,

5%,

10

watt,

wire

wound

120-001446

XV1,2.

Socket,

Electron

Tube,

Four-

Ceramic

120-001452

TBl

Terminal

Bou:i,

Four

double-screw

type

120-001447

TB2

Terminal

Board,

Ten

double-screw

type

120-001448

Ti

Transformer,

Power

120-001449

T2

Transformer,

Power

120-001450

V1,2

Tube,

Electron,

Type

866A

090-90866A

Figure

9.

Model

Mark

I1A

Power

Supply,

Cover

Removed,

Showing

Components.

Hallicrafters HT-45 MARK II A Training manual

Popular Amplifier manuals by other brands