Hallicrafters HT-41 Training manual

the hallicrafters co.

Figure 1. Hollicratters Model HI-41 Linear Ampli
GENERAL SPECIFICATIONS
Mode of Operation + Grounded grid class B linear power amplifier,
Power Consumption 5.22 -6eeeee ee 1500 watts maxioum, 117V, 60 cyclen, AC.
Input Impedance... « 40 ohms to 78 ohms,
Output impedance «+ 40 ohms to 75 ohms,
Drive
Power
in
Low
Drive
Position
..-
20
watts
approximately
Drive
Power
in
High
Drive
Position
0
watts
appranimately
Overalt
Dimensions
21-1/2
inches
wide
x
19
inches
deep
x
12-1/8
inches
high.
Net Weight ..-. . + 85 pounds
Shipping Weight Serer 7 pounds.
Plate Power fnput
ssa sow an
High
Drive
1200
watts
PEP
00
watts
350
watts
Low
Drive
1000
watts
PEP
600
watts
300
watts
‘In the High Drive pos
watts in Low Drive). The maxims
1s permissable to run 900 watte input in Keyed CW operation (800
n Key down time shall not exceed 30 seconds under this condition of

SECTION
|
GENERAL
1-1, INTRODUCTION.
The
Hallicrafters
Model
HT-41
is
a
linear
amplifier
using
two
RCA
7094
type
tubes
connected
as
high-mu
triodes
in
grounded-grid
class
Boper-
ation,
The
equipment
may
be
used
on
the
80-meter
through
10-meter
amateur
bands.
The
Model
HT-41
was
designed
as
a
companion
unit
for
the
Model
HT-37
but
may
be
used
with
the
Model
HT-32,
FPM-200,
or
any
20-watt
to
100-watt
exciter
with-
out the
need
of
an
external
pad
or
matching
net-
work,
The
linear
amplifier
incorporates
a
heavy
duty
plate
supply
and
employs
two,
type
866AX
mercury
vapor
rectifiers,
Excellent
dynamic
and
static
regulation
is
assured
through
the
use
of
17
microfarads
of
filter
capacity
and
a
wide-range
swinging
choke.
A
cut-off
bias
supply
is
included
and
provisions
have
been
made
for
applying
cut-off
bias
when
the
Model
HT-41
is
properly
connected
to
the
exciter
VOX
circuit.
The
broad-band,
low-impedance
(40
ohms
to
75
ohms),
input
circuit
eliminates
the
necessity
of
input
tuning,
making
neutralization
unnecessary
on
any
frequency
within
the
operating
range.
This
also
makes
the
operation
of
the
amplifier
extremely
stable.
A
heavy
duty,
optimum
"Q,"
multitap,
pi-
network,
output
circuit
allows
maximum
power
to
be
transferred
into
any
antenna
load
ranging
from
40
ohms
to
75
ohms,
1-2. TVI (TELEVISION INTERFERENCE)
SUPPRESSION.
Every
consideration
has
been
givento
mini-
mizing
possible
local
TVI
problems
in
the
design
of
the
Model
HT-41.
The
unit
incorporates
a
brute
force,
low-pass
line
filter,
full
RF
bypassing,
and
shielding.
A
ground
lug
has
been
provided
at
the
rear
of
the
chassis
for
an
external
ground
connec~
tion.
Itis
recommended
that
all
station
components
be
bonded
together
with
heavy
copper
wire
or
strap
and
connected
to
an
earth
ground.
Ground
leads,
which
are
equal
to
multiples
of
one-quarter
wave-
lengths
at
your
favorite
operating
frequencies,
should
be
avoided.
NOTE
With
any
high
power
installation,
par-
ticularly
in
fringe
reception
areas,
TVI
may
be
a
problem,
Should
this
occur,
it
is
recommended
that
a
high
quality,
low
pass
filter
be
used,
1-3.
ADDITIONAL
FEATURES.
Many
additional
features
are
included
inthe
Model
HT-41
for
reliability
and
ease
of
operation,
All
important
circuits
are
metered
by
means
ofa
three-position
meter
switch
and
an
easily
read,
il-
luminated,
front
panel
meter.
In
addition
to
reading
grid
current
and
plate
current,
the
meter
measures
RF
output
for
easier
tuning.
In
this
position,
both
the
plate.
and
output
TUNING
controls
are
adjusted
for
maximum
indicated
RF
output
voltage.
A
green
lamp
on
the
front
panel
indicates
that
power
is
ap-
plied
to
the
filaments,
bias
supply,
and
fan.
A
red
lamp
on
the
front
panel
indicates
that
the
high
volt~
age
supply
is
on,
All
band
switching
is
accomplished
by
a single
knob.
SECTION If
INSTALLATION
2-1.
UNPACKING.
When
removing
the
unit
from
the
carton,
do
not
attempt
to
lift
it
by
the
cover,
After
unpacking
the
amplifier,
examine
it
carefully
for
any
possible
damage
which
may
have
occurred
during
transit.
Should
any
sign
of
damage
be
apparent,
filea
claim
immediately
with
the
carrier
stating
the
extent
of
damage,
Check
all
shipping
tags
and
labels
for
spe-
cial
instructions
before
removing
or
destroying
them,
All
tubes
are
contained
ina
separate
carton
to
prevent
damage
tothe
tubes
during
shipment.
NOTE
Remove each tube from its carton only
when you are ready to install it, DONOT
USE
FORCE
when
inserting
tubes
in
sockets.

Remove
the
top
cover
of
the
amplifier
by
un-
screwing
the
four
side
screws
and
then
lifting
the
cover
completely
off
the
unit.
Remove
one
of
the
type
866AX
rectifier
tubes
from
the
carton
and
lo-
cate
the
four-prong
tube
sockets.
Insert
the
tube
into
one
of
these
sockets
so
that
the
two
larger
pins
engage
the
two
larger
pins
openings.
When
the
pins
engage
the
socket,
press
down
lightly
until
the
tube
is
seated
firmly
in
place.
Connect
the
plate
transformer
lead,
located
directly
behind
the
inserted
tube,
to
the
plate
cap
of
the
tube.
Remove
the
remaining
type
866AX
tube
from
its
carton
and
insert
it
into
the
other
four
prong
socket
the
same
as
above.
Connect
the
re-
maining
plate
transformer
lead
to
the
plate
cap
of
this
tube.
Remove
one
of
the
type
7094
tubes
from
its
carton
and
locate
the
recessed
tube
sockets
di-
rectly
in
front
of
the
fan.
Insert
the
tube
in
one
of
these
sockets,
the
largest
pin
on
the
tube
into
the
corresponding
largest
pin
opening
on
the
socket.
When
the
tube
engages
the
tube
socket,
press
down
lightly
until
the
tube
is
firmly
seated
inthe
socket.
DO
NOT
USE
FORCE.
Connect
the
plate
cap
(heat
radiating),
which
is
connected
to
the
parasitic
sup-
pressor
located
directly
in
front
of
the
tube,
to
the
plate
pin
on
top
of
the
type
7094
tube.
Tighten
the
holding
screw
on
the
plate
cap
firmly,
but
DO
NOT
USE
FORCE,
Remove
the
remaining
type
7094
tube
from
its
carton
and
install
it
into
the
remaining
7094
socket,
When
installing
this
tube,
use
the
same
procedure
as
above,
Replace
the
top
cover
and
secure
with
the
four
side
screws.
2-2.
LOCATION.
It
is
very
important
that
the
amplifier
be
placed
in
such
a
manner
that
complete
air
circula-
tion
is
available
on
all
four
sides,
the
top,
and
the
bottom.
The
air
intake
for
the
fan
is
situated
at
the
rear
of
the
top
cover.
Sufficient
air
space
must
be
maintained
around
the
unit.
Under
no
circumstan-
ces
should
any
object
be
placed
on
the
top
of
the
amplifier;
the
warm
air
is
exhausted
through
the
top.
2-3.
POWER
REQUIREMENTS.
The
Model
HT-41
Linear
Amplifier
is
de-
signed
to
operate
from
a
117-volt,
60-cycle,
power
source,
The
source
must
be
capable
of
si
ipplying
1500
watts
with
good
regulation
at
the
specified
line
voltage
if
maximum
capabilities
are
to
be
realized.
NOTE
Vf
in
doubt
about
your
power
source,
con-
tact
your
local
power
company
prior
to
inserting
the
power
cord
into
an
AC
pow-
er
outlet,
Plugging
the
power
into
the
wrong
power
source
can
cause
extensive
damage
to
the
unit,
requiring
costly
re-
pairs.
2-4. RF INPUT AND OUTPUT CONNECTIONS.
A,
RFINPUT.
-
The
input
connector,
located
at
the
rear
of
the
chassis,
will
mate
with
a
type
PL-259
coaxial
connector
(Amphenol
Type
83-1
SP).
The
output
of
the
exciter
should
be
applied
through
this
connector,
The
input
of
the
amplifier
is
designed
for
an
input
impedance
of
40
ohms
to
75
ohms,
IMPORTANT
For
best
performance,
the
input
cable
length
should
be
less
than
1/4
wave-
length
on
the
highest
operating
fre-
quency.
When
the
linear
amplifier
is
used
with
ex-
citers
having
less
than
60
watts
output,
a
jumper
should
be
placed
between
the
screw
terminals
on
the
"Drive
Level"
strip.
(See
Figure
3)
It
should
be
noted
that
the
efficiency
willbe
reduced
under
this
condition
of
operation;
there-
fore,
the
ratings
given
under
SPECIFICATIONS
should
be
adhered
to.
B.
RF
OUTPUT.
-
The
output
connector,
lo-
cated
at
the
rear
of
the
chassis,
will
mate
with
a
type
PL~259
coaxial
connector
(Amphenol
Type
83-
1SP).
Use
only
RG-8/U
coaxial
cable
for
the
output
feed
line.
Although
the
load
impedance
is
variable,
it
is
recommended
that
the
load
be
50
ohms
with
the
lowest
possible
VSWR.
2-5.
BIAS
AND
ANTENNA
RELAY
CONNECTIONS
It
is
recommended
that
coaxial-type
antenna
changeover
relays
be
used
with
the
Model
HT-41
Linear
Amplifier.
Cut-off
bias
should
be
used
in
all
modes
of
operation.
Figure
2
illustrates
how
to
connect
the
antenna
and
bias
switching
circuits.
The
Model
HT-
41
is
shipped
without
a
jumper
connected
between
the
screw
terminals
of
the
cut-off
bias
terminal
strip.

Figure 2
SECTION III
FUNCTION
OF
OPERATING
CONTROLS
3-1, FILAMENT SWITCH.
The FILAMENT switch atwo-ponitton togxle
awiteh, applies power to the filaments, fan, and
cut-off
blan
suppl,
3-2. PLATE VOLTAGE SWITCH.
‘The PLATE VOLTAGE switch a to-position
togele witch, applies power to the high voltage
supply.
3-3. METER SWITCH.
The
METER
SWITCH,
a
thee
witch,
selects
the
desired
circuit
to be
monitored.
The operator may select grid current, plate cur
rent, of RF output voltage
3-4. BAND SELECTOR.
The BANDSELECTOR switch, a six-ponttion
water switch, selects the desired amateur band,
This switch places » short acrosa the unused por-
tion ofthe tak coll and switchew in additional load
Ing capacitance on the 40, 75, and Wd-meter bands,
3-5. PLATE TUNING.
The plate TUNING coatrol a variable capaci
tor, resonates the plate eireutt at the desired re
mueney

el ‘© @ thehal
ficraftersc. ff
ae BS oveere|
Figure 4. Front Panel Controls
3-6, PLATE LOADING.
The
plate
LOADING
control,
a
variable
capa-
citor,
adjusts
the
output
impedance
to
the
antenna
load
impedance
(40
ohms
to
75
ohms),
3-7. METER
The
meter
provides
an
accurate
indicatior
for
tuning
the
amplifier.
The
meter
indicates
gric
current
(0
to
400
MA),
plate
current
(Oto
800
MA)
and
RF
output
voltage
(0
to
400V).
SECTION iV
OPERATING PROCEDURE
4-1. GENERAL.
When
tuning
the
Model
HT-41,
it
is
important
that
both
the
plate
TUNING
and
plate
LOADING
con-
trols
are
adjusted
for
maximum
RF
output
as
indi-
cated
on
the
RF
output
voltmeter.
NOTE
Power
input
should
always
be
a
direct
function
of
the
applied
excitation.
Never
attempt
to
control
the
power
input
with
the
loading
adjustments.
A
monitor
oscilloscope
should
be
used
for
best
results
in
all
modes
of
operation,
(especially
SSB,
AM,
and
DSB),
as
the
one-quarter
second
me-
ter
(FCC
requirement)
will
not
follow
voice
peaks
and,
of
course,
in
no
way
indicates
true
power
in-
put
under
voice
operations,
Some
of
the
many
factors
which
influence
the
indicated
power
input
are
the
degree
of
damping
in
the
meter,
individual
voice
characteristics,
micro-
phone
frequency
response
characteristics,
exciter
audio
bandwidth
response,
etc,
In
normal
SSB
operation,
the
plate
current
meter
will
indicate
approximately
300
MA
on
voice
peaks
(High
Drive).
If
the
Low
Drive
position
is
used,
the
plate
current
meter
will
indicate
approxi-
mately
250
MA
on
voice
peaks.
Before
attempting
to
operate
the
Model
HT-
41,
the
following
items
should
be
checked:
1.
All
station
components
should
be
bonded
together
and
connected
to
an
earth
ground,
2.
The
output
should
be
connected
toa
50-
ohm
antenna
load
through
an
RG-8/U
transmission
line,
NEVER
OPERATE
THE
MODEL
HT-41
WITH-
QUT A LOAD.
3.
The
input
should
be
connected
to
the
ex-
citer
through
the
coaxial
cable.
For
best
results,
this
cable
should
be
less
than
a
one-quarter
wave
length
long
at
the
highest
operating
frequency,
4,
The
cut-off
bias
terminalson
the
screw
type
terminal
strip
should
be
connected
to
the
ex-
citer,
as
shown
in
figures
2
and
3,
5.
The
FILAMENT
andplate
switch
should
be
in
the
OFF
position.
CAUTION
NEVER
CONNECT
THE
MODEL
HT-4t
TO
AN
AC
LINE
WHEN
THE
ABOVE
SWITCHES
ARE
IN
THE
ON
POSITION,

4-2.
TUNING
PROCEDURE.
The
following
procedure
applies
ta
all
modes
of
operation:
1.
Place
the
FILAMENT
switch
in
the
ON
position
to
apply
voltage
to
the
green
pilot
lamp,
the
tube
filaments,
the
bias
supply,
andthe
fan.
NOTE
Allow
four
minutes
minimum
filament
warmup
time
before
applying
plate
volt~
age,
2,
Set
the
BAND
SELECTOR
switch
tothe
desired
band.
3.
Set
the
METER
SWITCH
to
PLATE,
4,
Place
the
HIGH
VOLTAGE
switch
in
the
ON
position.
4-3.
CW
OPERATION
(High
Drive).
1.
Assuming
the
filament
and
plate
volt-
ages
have
been
applied,
carefully
increase
the
CW
output
on
the
exciter
until
the
plate
meter
on
the
Model
HT-41
reads
approximately
150
MA.
2.
Turn
the
METER
SWITCH
on
the
Mode}
HT-41
to
RFO
and
adjust
the
plate
TUNING
and
plate
LOADING
controls
for
maximum
upward
de~
flection
on
the
meter.
3.
Set
the
METER
SWITCH
to
PLATE
and
again
increase
the
exciter's
output
until
the
Model
HT-41
plate
current
reads
approximately
300
MA,
4,
Set the
METER
SWITCH
to
RFO
and
again
adjust
the
plate
TUNING
and
plate
LOADING
for
maximum
upward
meter
deflection.
65,
Set
the
METER
SWITCH
to
PLATE
and
increase
the
exciter's
output
until
the
Model
HT-41
plate
current
reads
400
MA.
6,
Set
the
METER
SWITCH
to
RFO
and
again
adjust
the
plate
TUNING
and
plate
LOADING
controls
for
maximum
upward
meter
deflection.
If
the
plate
current
meter
indicates
400
MA
with
the
plate
TUNING
and
plate
LOADING
controls
adjust-
ed
for
maximum
RFO
upward
meter
deflection,
the
amplifier
is
correctly
loaded
for
700
watts
average
DC
input.
7. Jf
it
is
desired
to
operate
the
Model
HT-
41
at
the
900-watt
input
level,
the
exciter's
output
should
be
increased
until
the
plate
current
meter
indicates
500
MA
with
the
plate
TUNING
andplate
LOADING
controls
adjusted
for
maximum
RFO
up-
ward
meter
deflection.
CAUTION
If the plate current is increased beyond
400 MA, as in step 7, the tuning adjust-
ments
should
be
made
as
rapidly
as
possible. Excitation should not be ap-
plied
at
the
500
MA
level
for
more
than
30 seconds.
Ifthe
Low
Drive
position
is
used
(that
is,
with
the
jumper
across
the
drive
level
terminal
strip
and
the
exciter
with
less
than
60
watts
output),
the
tuneup
procedure
will
be
the
same
as
described
in
steps
1
through
5,
However,
the
last
plate
TUNING
and
plate
LOADING
control
adjustment
is
to
be
made
at
335
MA
plate
current
(600
watts
input).
If
it
is
desired
to
operate
at
the
800-watt
in-
put
level
using
the
Low
Drive,
the
last
plate
TUN-
ING
and
plate
LOADING
control
adjustments
should
be
made
at
450
MA
plate
current
(800
watts
input),
CAUTION
If
the
plate
current
is
increased
beyond
335
MA
in
Low
Drive,
the
tuning
adjust-
ments
should
be
made
as
rapidly
as
pos-
sible,
Excitation
should
not
be
applied
at
the
450
MA
level
for
more
than
30
sec-
onds.
4-4. SSB OPERATION (High Drive}
1.
Follow
steps
1
through
7
as
describedin
paragraph
4-3.
2.
Switch
the
exciter
to
the
SSB
position
and
adjust
the
microphone
gain
until
the
Model
HT-41
plate
current
meter
indicates
approximately
300
MA
on
voice
peaks,
or
until
flat-topping
is
indicat-
ed
on
a monitor
oscilloscope.
NOTE
If the Low Drive position is used, the
tuneup procedure will be the same as de-
scribed
above
except
that
the
last
plate
TUNING andplate LOADING control ad-
justment is to be set at 450 MA plate
current
(See
Low
Drive
CW).
The
exciter
microphone
gain
should
be
ad-
justed
to
the
point
where
the
Model
HT-41
plate
current
meter
indicates
approximately
250
MA
on
voice
peaks,
or
until
flat-topping
occurs
ona
mon-
itor
oscilloscope.
4-5. AM OPERATION (High Drive).
1.
Adjust
the
Model
HT-41
plate
TUNING
and
plate
LOADING
controls
as
described
in
steps
1 through
7 of paragraph
4-3.

2. Switch the exciter tothe AM(DSB) posi-
tion and adjust the exciter output until the Model
HT-41 plate current meter indicates 200 MA.
There will be a slight change inplate current with
modulation.
NOTE
If Low Drive position is used, the loading
adjustments will be the same as de-
scribed for the Low Drive SSB proced-
ure previously described, The exciter
output should be adjusted so that the Mo-
del HT-41 plate current will be 170 MA.
4-6. CALCULATING POWER INPUT.
Round numbers have been used in the loading
instructions. To determine the average DC plate
power input, multiply the plate current by 1800
volts (500 MA x 1800 volts = 900 watts).
Meter readings will be accurate only when
steady CW input is being measured, Aspreviously
mentioned, many factors influence the indicated
plate current on SSB, Therefore, no meter can give
a true indication of the plate power input on SSB.
NOTE
On some frequencies at low power le-
vels, the plate LOADING control may not
reach a definite peak during the process
of loading. Should this condition occur,
leave the plate LOADING control at the
point which gives the greatest RFO indi-
cation and continue to the next loading
step described in the above procedure,
This condition will rectify itself at nor-
mal operating levels.
SECTION V
SERVICE DATA
5-1, WARNING HIGH VOLTAGE.
DC voltages in excess of 2000 volts are pre-
»
sent
in
this
equipment.
DO
NOT
attempt
to
mea-
sure voltages with hand-held test leads or to ser-
vice 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 fre-
quency burns can be caused by coming in contact
with, or in close proximity to, the plate and output
circuits,
CAUTION
Use extreme caution when working with
this equipment,
5-2, CLEANING.
Equipment that is power-cooled may tendto
collect dust within the unit, depending on the con-
tent of the air being circulated.
All components should be kept clean, as any
accumulation
of
dust
in
the
high
voltage
or
RF
areas may cause arcing and consequent damage.
This
applies
to
the
top,
bottom,
and
sides
of
the
chassis.
Both
the
plate
tuning
and
loading
capaci-
tors should be cleaned frequently to prevent arcing
between plates.
CAUTION
Do not nick or bend capacitor plates,
Never use solvents for cleaning. The
preferred method of cleaning is the use
of a vacuum cleaner while dusting with a
clean, flexible, bristle brush.
5-3. LUBRICATION.
Both the front and rear fan bearings should
be lubricated with SAE No, 10oil. This can be ac-
complished by saturating the felt storage pads with
oil twice a year.
5-4. SERVICE OR OPERATION
QUESTIONS.
For further information regarding operation
or servicing of the Model HT-41 Linear Amplifier,
contact your Hallicraiters dealer.
The
Hallicrafters
Company
maintains
an
ex-
tensive
system
of Authorized
Service
Centers
where
any
required
service
will
be performed
promptly
and
efficiently
at a nominal
charge,
All
Hallicrafters
Authorized
Service
Centers
display
the sign
shown
on next
page.
For the location
of the
one
nearest
you,
consult
your
dealer
or telephone
directory.
Make
no service
shipments
to the

factory
unless
instructed
to
do
so
by
letter,
as
The
Hallicrafters
Company
will
not
accept
the
respon-
sibility
for
unauthorized
shipments.
The
Hallicrafters
Company
reserves
the
privilege
of
making
revisions
in
current
production
of
equipment
and
assumes
no
obligation
to
incorpo-
rate
these
revisions
in
earlier
models.
SECTION
VI
SUPPLEMENTARY
DATA
6-1,
NEUTRALIZATION,
No
neutralization
is
necessary.
Grounded
grid
operation,
low
impedance
input,
and
excellent
shielding
and
bypassing
assures
complete
stability
at
all
times.
6-2.
GRID
CURRENT.
Grid
current
will
be
approximately
80
MA
to
100
MA
on
SSB
voice
peaks.
Under
no
circumstan-
ces
should
the
grid
current
be
allowed
to
exceed
200
MA
maximum,
NOTE
Grid
excitation
should
always
be
remov-
ed
from
the
amplifier
before
the
HIGH
VOLTAGE
switch
is
placed
in
the
OFF
position,
6-3.
IDLING
PLATE
CURRENT.
The
Model
HT-41
will
have
an
indicatedidling
.
plate
current
of
approximately
85
MA
when
bias
is
not
applied.
6-4.
PLATE
CURRENT.
The
indicated
plate
current
on
SSB
voice
peaks
(High
Drive)
1200
watts
PEP
input
will
be
approximately
300
MA,
Low
Drive
-
250
MA
will
be
1000
watts
PEP,
6-5.
PLATE
VOLTAGE.
The
plate
voltage
will
be
approximately
1800
volts
with
a
400-MA
load
at
117
volts
AC
input,
6-6.
RF
OUTPUT
VOLTMETER.
This
voltmeter
is
connected
across
the
out-
put
coaxial
cable
and
indicates
maximum
output
voltage
This
meter
isnot
accurately
calibrated
and
is
to
be
used
asa
tuning
indicator
(always
tune
for
maximum
voltage
readings
for
a
given
plate
cur-
rent).
As
this
is
not
a
peak
reading
voltmeter,
voice
peaks
will
deflect
the
meter
approximately
one~
third
of
the
equivalent
CW
output.
6-7.
TUBE
COOLING.
A
small
cooling
fan
is
included
in
the
unit
to
keep
the
tubes
and
related
parts
within
their
rated
temperature
limits.
Never
operate
the
amplifier
if
the
cooling
fan
is
inoperative.

vl
NOTES:
ca
2000 , 2500V ca
Fi
RFC4 12 AMP
UNLESS OTHERWISE SPECIFIED ALL
RESISTOR
VALUES
IN
OHMS
,CAPACITOR
VALUES IN MFD.
C1,C2,03,C4,C5,C6,Ci4,Ci5 C16 VALUES
ARE OOS MFD,500V.
.
C26,
C27,C28,C29,
C30,C31
VALUES
ARE
-O1MFO,1-4KY,
C19, C20,C21, C22 C23, C24 VALUES ARE
IOOMFD, 450 V.
RI, R2,R3, R4,R5,R6 VALUES ARE
20K OHMS , 10 W.
Figure 7.
at
Schematic Diagram for HT-41 Linear Amplifier.
ey
cR2
Te,
T
61

cB
2000, 2500
Ll
089- 002738
e 7. Schematic Diagram for HT-41 Linear Amplifier.

Schematic
Symbol Description
CAPACITORS
C1,2.3,4, 0.005 mfd,, 500V, Cer, Disc
5.6,14,15.
16
C782 0,001 mfd., 3KV, 20%,
Cer, Disc
ce
0,002
mfa.,
2500
WDC,
10%, Mica
ca Variable Capacitor, PLATE
TUNING
€10,11 500 mmf., 1000 WYDC,
5%, Duramica
cla
Variable
Capacitor,
LOADING
C13 36 mmf, 300V, 10%,
Duramica
17.25 0.001 mfd., 500V, Cer, Dise
cig 0.47 mfd,, 200V, 20%, Mylar
C19,20, 100 mfd., 450V, Electrolytic
21,22,23,
24
26,27, 0,01 mfd., 1400V, Cer, Dise
28,29,30,
31
RESISTORS
R1,2,3,4,
20K
ohm,
10%,
10W,
W.W.
5,6
RT 18K ohm, 10%, 2W
RB 330 ohm, 10%, 1W
RO 10K ohm, 10%, 1W
R10 1K ohm, 10%, 10W
RIL
200
ohm,
10%,
10W,
W.W.
R12 100K ohm, 10%, 1W
R13 1 megohm, 10%, 1W
COILS AND TRANSFORMERS
Li Coil, Tank Final Plate
L2 Choke, Swinging
PS1,2 Choke, Parasitic Yau
RFC1 Choke, RF Cathode
RFCZ Choke, RF Plate
RFC3 Choke, RF Safety
RFC4,5 Choke AC Line
Tl Transformer High Voltage
TE Transformer Filament
SERVICE PARTS LIST
Hallicrafters
Schematic
Part
Number
Symbol
047-100168
T3
047-100397
470-943202
SW1,2
sw3
048-000507
sw4
493-410501-244
048-000527
461-153360
047-200230
046-001302-05,
047-000783
VL,2
¥3,4
PLI
PL2
CRI
cR2
047-200752
445-032203
451-652183
45)-352331
451-352103
445-032102
024-001390
Fl
451-352104
451-352105,
S12
LA1
Mi
051-003159
056-000457
053-000655
053-300276
053-000624
053-200444
053-000628
052-000884
052-000892
Description
Transformer Filament
and Bias
SWITCHES
Switch, Toggle, DPST
Switch, Rotary; BAND
SELECTOR
Switch, Rotary; METER
KNOB AND SKIRTS ASSEMBLIES
Hallicrafters
Par’
Number
COILS
AND
TRANSFORMERS
(Cont.)
052-000888
060-002276
060-002274
060-002347
Knob, TUNING and LOADING 015-001723
Knob, METER SWITCH
Knob, BAND SELECTOR
Tube, RF Amplifier 7094
Tube, Rectifier 866AX
Lamp. Pilot No. 47
Lamp, ruvt No, 1486
Diode, Germanium 1N295
Diode, Silicon
MISCELLANEOUS
Blade, Fan
Cabinet, Bottom
Cabinet, Top
Cap, Plate
Fuse (12 amp, 250V, 3AB)
Fuse Holder
Connector, Coaxial
Line Cord
Meter
Motor, Fan
Panel, Front
Board, Printed Circuit
Socket
Ass'y
Pilot
Light
{Red)
Socket Ass'y Pilot Light
(Green)
Connector, Heat Raciating
Lock Ling Cord
Trim Strip
015-001725
015-001722
TUBE3, LAMPS, RECTIFIERS AND DIODES
090-001445
090-901185
039-100004
039- 10049
019-301980
019-002798
080-000782
066-702447
066-003168
076-100008
039-100497
006-100451
010-100056
087-104690
082-000531
020-000321
068-001178
129-000553
086-000562
086-000571
076-003622
076-100953
007-000815

KAXL's “# BAMA
This manual is provided FREE OF CHARGE from
the “BoatAnchor Manual Archive” as a service to
the Boatanchor community.
It was uploaded by someone who wanted to help
you repair and maintain your equipment.
If you paid anyone other than BAMA for this manual,
you paid someone who is making a profit from the
free labor of others without asking their permission.
You may pass on copies of this manual to anyone
who needs it. But do it without charge.
Thousands of files are available without charge
from BAMA. Visit us at http://bama.sbc.edu