Heathkit GR-61 Assembly Manual
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FM
PORTABLE
RADIO
MODEL
GR.6I
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{
TYPICAL
COMPONENT TYPES
This
chart
is a
guide
to commonly used types
of
elec- tions should
prove
helpful in identifying
most
parts
and
tronic
components. The symbols and
related illustra-
reading the
schematic diagrams.
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ITTTT
I
EARTH GROUND
CHASSIS GROUND
CONOUCTORS
Assembly
and
Operation
of the
FM
P O
RTAB
LE
RAD
IO
MODEL
GR-61
'===*=,
HEATH
COMPANY
BENTON
HARBOR,
MICHIGAN
TABLE
OF
CONTENTS
Specifications.
. .
.
Introduetion.
Circuit
Description.
Parts
List.
Step-By-Step
AssemblY
Circuit
Board
AssemblY.
.
.
Right
End
Plate
Parts
Mounting.
Left End
Plate
Parts
Mounting.
Circuit
Board
Mounting.
. .
Wiring Circuit
Board
To
End
Plates.
.
..
Final
Wiring
Final Assembly.
.
.
Initial
Test
And
Adjustment.
. .
Cabinet
AssemblY.
Operation.
In
Case
Of
DifficultY
Troubleshooting
Chart.
Introduction
To
Transistors.
.
.
Glossary
Of
Radio
Terms.
Circuit
Board
X-RaY
View.
(fold-out
from
Page).
.
. .
.
Cqyrlghto
t962
12/3O/66
2
3
3
D
30
31
SPECIFICATIONS
Tuning
Range.
Intermediate
Frequency (IF').
. .
Sensitivity.
Controls.
Transistors.
Antenna.
Speaker.
Batteries.
Normal
Battery
Life.
.
Accessory
Jack.
.
Size.
.
Net
Weight.
The Heath
Company
reserves the
right
to discon-
tinue
instruments
and to
change specifications
at
any
time
without
incurring any
obligation
to
88 to
108 megacycles.
10.7
megacycles.
3
uv for
20 db
quieting
(average),
5 uv for 20
db
quieting (maximum).
(Measurements
takenin
aligned
condition.
)
Volume,
Tone,
and AFC.
3
-
2N174?
4
-
2Nt274
1
-
2N24e5l
1
-
2N26711
in FM
tuning
unit
1
-
2N26541
Collapsible
whip
with
provisions
for
external
300 Q
antenna.
4r x
6t'
oval,
permanent
magnet
type.
Six l-l/2
volt
size
C
cells.
300-500
hours.
Earphone
or
hi-fi
output.
9-L12"
wide x 1-l/Q,,high
x 4"
deep.
3 lbs.
incorporate
new features
in instruments
pre-
viously
sold.
I
*
)
_--I
l@l
n*"g
INTRODUCTION
Your
new
FM Portable
Radio
featuresadepend-
able
10-transistor
circuit,
housed
in
an attractive
imitation-leather
case.
The
front
of
the
case is
made
of durable
high-impact plastic.
Exceptionally
high
quality
is designed
into
this
Radio,
as
evideneed
by ttre
preassembled
and
prealigned
FM
tuning
unit, and
the
prealigned
IF
and
ratio
detector
transformers.
-ThreJIF-
limiter
stages,
plus
a ratio
detector
combina-
tion
with
AFC, provide
stable
FM
reception. The
push-pull
audio
power
amplifier
circuit delivers
more
than
adequate power
for the
4" x
6"
speaker
to give
large-room
sound
coverage.
CIRCUIT
DESCRIPTION
The
preassembled
and
prealigned
FM tuning
unit contributes
to
ease
of
assemblyandinsures
consistently
good
FM
performance.
A
heavy-
duty
circuit
board
is used
to further
simplify
assembly
of
the
kit.
If
you
are not
familiar
wlth
electronic
circuitrv
and
terminology,
you
may
find it helpful to
reai
the
I'Introduction
To
Transigtorsr
and
"Glossary
Of
Radio
Terms"
beginning
on
Page
2?
of
ttre
manual.
This
information
should
prove
helpful
in
understanding
how
your
Radioworkswhenyou
read
the
following
Circuit
Description.
The
circuitry
of the FM
Portable
Radioconsisrs
of
the
RF, IF-limiter,
ratio detector,
and
audio
sections.
For
simplicity,
each
section will
be
discussed
separately,
Refer
occasionally
to the
Schematic
Diagram
while
reading
tris
descrip-
tion.
To
help
in
reading
the
Schematic,
the
letter-
number
designations
for
t}e
circuit
parts
are
number
coded
as follows: #1
to
gg
for the FM
tuning
unit, and
#100 to
200 forthecircuit
board
and
chassis.
For
example,
resistor
R3 ig in the
FM
tuing
unit, and
resistor
R,103
is
onthe cir-
cuit
board.
NOTE:
Refer
to
the
"Kit
Builders
Guide"
for
complete
information
on unpacking,
parts
identi-
fieation,
tools,
wiring,
soldering, and
step-by-
e
RF
SECTION
The
RF
section
contains
the
RF amplifier,
oscillator,
and
mixer
stages,
all
in
i
pre-
assembled
and
prealigned
tuning
unit.
FM
signals
from
the
antenna
are applied
to
transformer
T1
,
which
matches
the
antenna
to the
first
section
of
the tuning
capacitor,
C1A. This
portion
of
the
tuning
capacitor tunes
ttre
emitter
circuit
of RF
amptifier
Ql
to the
desired
FM
station
frequency.
C1B,
the
second
section
of
tlte
tuning
capacitor,
tunes
the
collector circuit
of
Q1
to the
same
station
frequency.
Q2
is
operated as
a feedback
tuned-collector
oscillator at
10.?
megacycles
above the
fre-
quency
of
the
desired
FM
station. The
ampli-
fied
FM
station frequency
from
Q1,
and the
oscillator frequency
from
Q2
are mixed
in
Q3
to
provide
a
difference
frequency
of
10.7
meg-
acycles. This
difference
frequency
is coupled
tirough
transf
orme r T2,
out
of
the
preas
se mble d
tuning
unit,
to the
first IF
amplifier,
Q4.
I
t
I
l
I
I
1
-l
I
{
n"u"a
@EGBI
The circuit of
the
P.E.C.
includes
a
de-empha-
sis
network
to
compensate
for high
frequency
pre-emphasis
that was
added to
the transmitted
audio
signal;
it thus
provides
a
flat audio
fre-
quency
response.
This network
also attenuates
frequencies
above
the audio range.
The audio
output
signal
of
the ratio
detector is
applied
both
to
Q7,
the
emitter
follower
and, as
an
AFC
voltage,
to
Q2
oftheFMtuning
unit.
Any
shift of
the
IF from
the
10.7
megacycle
center
frequency
appears
as
a DC voltage
which
is ap-
plied
to
diode D1;
this is
commonly
called
AFC
voltage.
The
DC
voltage
shift on
D1 in
turn
changes
the oscillator
capacity,
thereby ef-
fectively retuning
it and causing
it to
track the
particular
station
that is
being
received.
AUDIO
SECTION
The audio signal
from
the ratio
detector is
applied to
Q7,
the emitter
follower,
which acts
as
a matching networkbetween
the
ratio
detector
and
the Volume control.
After
the Volume control,
the audio signal
is amplified
bydriver
amplifier
Q8
and
then
to the
Tone
control
and
to driver
transformer
T6. Transformer
T6
couples
the
audio signal
to
Q9
ahd
Q10,
ttte
push-pull
audio
amplifier stages.
From
Qg
and
Q10
the signal,
is coupled
to the speaker
and
earphone
jack
through
T?,
the audio output
transformer.
When
an
earphone is
plugged
in,
the built-in
speaker
is automatically
disconnected
from
the
circuit
and
the
audio signal
goes
instead
to the ear-
phone.
Operating
power
is supplied
by six
1-1/2
volts
size
C
flashlight
batteries.
IF-LIMITER
SECTION
The
10.?
megacycle signal
from
the
FM tuning
unit is
appliedto
Q4,
the
first IF amplifier.
From
Q4,
the
IF signal
passes
through
transformer
T3'
which
passes
only
the difference
frequency
of 10.?
megacycles,
to
Q5,
the
second
IF amplifier.
After
additional amplification
in
Q5,
the signal
is
applied
through T4, the second
IF transformer,
to
limiter stage
Q6,
which limits on
all but
the
weakest
signals.
Stages
Q4
and
Qb
act as
IF amplifiers
for
weak
signals,
and
as limiters
for
strong
signals.
Limiter
stages
are used
to remove
any
AM
(amplitude
modulation)
of
the IF signal,
and
to
limit
the signal
to
the
proper
level
for
the ratio
detector.
The IF signal
from
limiter
Q6
is next
applied
to ratio
detector transformer,
T5.
RATIO DETECTOR
Ideally,
the IF
signal
applied
to
the ratio
de-
tector should be of constant
amplitude,
but con-
tain
variations
in frequency
which
correspond
to
tfie audio signal being
transmitted
by
the
FM
station.
The
amount of
frequency
deviationfrom
the center
frequency of
10.7
megacycles
de-
termines
the amplitude of
the resulting
audio
signal.
The number of
times
per
second
thatthe
IF
signal
deviates from 10.?
megacycles
de-
termines
the resulting
audio
frequency.
The
combinatlon of
diodes D3, D4, and
transformer
Tb detect frequency variations
in the
IF
signal,
and
change
these variations
into
anaudiosignal.
Most of
the resistors
and capacitors
used
inthe
ratio
detector
are encapsulated
in a
P.E.C.
(pack-
aged electronic
circuit).
The
use of
this
P.E.C.
eliminates
any variations
in
performance
that
could
result
from
different
wiring
techniques.
@EE@l
P"e"s
PARTS
LIST
The
numbers in
parentheses
in the Parts List
are keyed
to the
numbers in the Parts drawings
to aid in
parts
identification.
PART
No.
PARTS
Per
Kit
DESCRIPTION
4.7
Q
(yellow-violet-gold)
10 Q
(brown-black-black)
68 A
@Iue-gray-black)
220 Q
(red-red-brown)
820 A
(gray-red-brown)
1
KO
(brown-black-red)
1.2
KO
(brown-red-red)
2.?
KO
(red-violet-red)
3.3 KO
(orange-orange-red)
4.1 KA
(yellow-violet-red)
6.8 Kft
(blue-gray-red)
10 KO
(brov'n-black-
orange)
t2 KQ
(brown'red-orange)
15 KO
(brown-green-orange)
18
KO
(brown-gray-orange)
22 KA
(red-red-orange)
68
Kf)
(blue-gray-orange)
1 00 KO
(brown-
black-
yellow)
1 megohm
(brown-black-
green)
PART
PARTS
No.
Per
Kit
Controls-Switch
(5)
10138- 1-
"
(6)
1e-81
(?)
60-18 1
Choke-
Transf
ormers-
Diode
DESCRIPTION
100
KO linear
control
10 KQ
control
with SPST
switch
SPST
switch
Resistors
(1)
1:T20
t-4L
L-2
t-45
1-8
1-9
1-
10
1-
13
t-r4
1- 16
1- 19
L-20
1-109
L-21
1-69
t-22
1-60
r-26
1-
35
Capacitors
(2)2
-
2t-46
2t-94
(3)
25-54
(4)
25- 11 5
25-116
25-tl?
25-11 1
(8)
45-35
(e)
sr-sz
51-98
(10)
52-57
53-6
(11)
56-26
(81
(10)
2
1
1
2
1
I
1.?
ph
choke
Driver transformer
Output
transformer
IF transformer
Ratio detector transformer
Crvstal
diode
1
I
I
1
4
I
2
1
210
ttttf
disc
ceramic
.005
pfd
disc ceramic
.05
pfd
disc
ceramic
10
pfd
15
V tubular
electro-
lytic
10
pfd
15
V
electrolytic
50
pfd
15
V
electrolytic
100
pfd
15
V
electrolytic
1000
pfd
15
V tubular elec-
trolytic
tzt
1-7
\\=t-
/-
{4r lf-----------v
l-
^r--
J"
'::-
a
{
n'u"u
@EEFI
PART
No.
PARTS DESCRIPTION
Per
Kit
PART
No.
PARTS
DESCRIPTION
Per
Kit
Transistors
4t7
-10
1
411
-7t
1
411
-72
1
411
-57
3
tt7-2
1
2N2671
transistor
tuning
unit)
2N2654 transistor
tuning
unit)
2N2495 transistor
tuning
unit)
2Nl74? transistor
Transistor
package
contain-
ing four
part
no.417-21,
type
2N1214 transistors
3-48
x 1/4" screw
4-40
x
1/8" setscrew
6-32
x 3/16" screw
6-32
x l/4" screw,
phillips
head
6-32 x L/4"
sctew, binder
head
6-32
x
3/8"
screw
6-32
x
3/8"
self-tapping
screw
6-32 x l/2"
screw
(in
(in
(in
Hardware
(cont?d.
FM
(18)
254-?
I
(1e)
254-e
2
FM
(20)
254-1 1
(2r)
254-14 2
FM
(22)254-4
1
#3
lockwasher
#4 lockwasher
#6 lockwasher
Small
control lockwasher
Large
control
lockwasher
i
t-
t
I
!
I
Hardware
(1)
250-4e
(2)
250-156
(3)
250-138
(4)
250-22s
(5)
250-56
(6)
250-8e
(?)
250-106
(8)
250-10
343-?
344-50
344-1
6
344-t5
346-1
[
]
${ilrlr
(2)
fo
(3}
frfril
ro
flinm
,rr,-rz+rQ2
,-,F
(16)@
e7l
I
^
(5)
^
(61
^
(71
,
(8)
fl,',ii',',i
l,p,i,'*rr
gF**
t}.**t
I
2
8
3
d
2
n
4
@
@
4
2
1
1
2
4
10
4
2
wire
wire
wire
(s)
252-r
(10)
252-15
(11)
252-3
(L2)
252-22
3-48
nut
4-40
nut
6-32
nut
6-32
speednut
(ls)
@
(16)
(l
z1
@
g
(r
a1
(l
e)
(20)
(21
)
ezl
@@@@@
.
r3)
255-11
(24)
25e-rt
(25)
25e-12
(26)
455-31
(2?)
258-30
Metal Parts
(Zg)
tOO-rr,rarO
r
(2e)
1oo-M41?
1
(30)
zo4-Mb1?
1
Cable-Wire-SleevinE
Tapped
spacer
Spade
lug
Large
solder lug
Antenna
bushing
Battery
spring
Length
shielded cable
Length
black hookup
Length
stranded
red
Length
stranded black
Length sleeving
Switch
lever
Bottom
circuit board
bracket
Top
circuit board bracket
ota:lno)g rlr).
urt&
Small control
nut
Large control
nut
Flat
washer
Thin
nylon shoulder
washer
Thick nylon
shoulder
washer
(13)
(14)
(13)
252-3e
(r4)
252-7
(15)
253-45
(16)
?5-18
(1?)
2b3-Eo
3
1
2
1
I
r*
Page
T
PART
No.
PARTS
DESCRIPTION
Per
Kit
Metal Parts
(cont'd.)
(1)
mA:IFI0--T------Tntenna bracket
(2)
205-M391
(3)
205-M392
(4)
46e-Ml3
85-51F831
92-9
93-8
110-14
391
-23
401-19
(6)
431
-6
(?)
434-110
(8)
436-16
462-81
462-r8r
462-89
462-175
490-1
490
-2
3
tr42-42
390
-1
58
(e)
214-30
(10)
i214-31
(1
1)
?3-4?
331
-6
595-593
Right
end
plate
Left end
plate
Batterv contactor
1
1
1
I
I
1
1
I
1
1
1
7
I
1
I
1
2
1
1
1
1
1
2
3
1
P.E.C.
(packaged
electronic
circuit)
Circuit
board
Cabinet
front
Leather
case
FM tuning
unit
Nameplate
Spealer
2-screw terminal strip
Transistor
socket
Earphone
jack
Small tuning larob
Large tunlng knob
Volume
knob
Tapered knob
Alignment tool
Allen
wrench
Collapsible
antenna
Battery
label
Battery
holder
Battery
holder end
Sponge
rubber
pad
Solder
Manual
,?"€r
\-----
_.-TOP
SIDE
,f
NOTE:
SOCKETS MUST
@@
11.
(
)
Conn
AFC.
circr
(
)
Referring
length
of
CUT
THE
CAE
BELOW.
PRE
TAKING CAR€
OF
THE
SHIEI
INSULATION.
PEEL OFF
TI'
THIN WIRES
(
Defoi
Detoil
lA
dj,
BE INSERTED FROM
THE TOP
(LETTERED}
SIDE
OF THE CIRCUIT
BOARD.
THIS IS
THE
SIDE
OPPOSITE THE
METALIC FOIL.
,,1,::
ir
REMOVE
THE
SMALL
IYIRES
AMOUNTS
OF
LEAD
ANO
TH
SOLDER
--{
v
L2.
(
)
Ator
w'ire
(s-1)
othe:
heat
may
resu
leadr
conn
KEYWAY
ttB
Detqil
lC
.:1::
t1.r
;::1i
Page
8
Before starting
Builders
Guide
wiring,
solderit
procedures.
CIRCUIT
BOARI
(
)
Referring
t
mount
the I
circuit
boal
lettered
si<
socket
Posi
of
the
circu
align
ProPe
all
four
Pir
lrcard.
Be
r
unused
hole
(
)
Referring
tapped spa
the
circuit
These
spac
keep
it le'
rePositione
Proceed
to
Pic
steps
surroundi
Refer
to
Picto
(
)
Remove
th
lettered
sit
them on
th
using
tlte s
PICTORIAL
3
PICTORIAI
I
PROCEED
TO
PICTORIAL
2
STEP.BY.STEP
ASSEMBLY
|@E
11.
(
)c
A
ni
Before
starting
to
assemble
this
kit,
readthe Kit
Builders
Guide
for
complete
information
on
wiring,
soldering,
and
step-by-step
assembly
procedures.
CIRCUIT
BOARD
ASSEMBLY
(
)
Referring
to
Detail
1.{
(on
Pictorial
1),
mount
the
seven transistor
sockets
on
the
circuit
troard. Insert
the
sockets from
the
lettered
side
of
the
board. Be
sure each
socket
positioning
tab fits
into the keyway
of
the
circuit
board, and thatthe
socketpins
align
properly
with
the foil
pattern.
Solder
all
four
pins
of
each socket to the
circuit
board.
Be
careful not to
solder
any
of
the
unused holes
in the
circuit
board.
(
)
Referring
to
Detail
18, mount
the
four
tapped
spacers
on
the
lettered
side of
the
circuit
board.
Use
6-32
xg/g,,screws.
These
spacers
will
support
the
board
and
keep
it
level.
They
will
be
removed
and
repositioned
later.
Froceed
to
Pictorials
1 and
2 and
perform
the
steps
surrounding
the
illustrations.
Refer
to Pictorial
3
for the
following
steps.
(
)
Remove
the
four
tapped
spacers
from
the
lettered
side
of the
circuit board.
Then
mount
them
on
the
foil
side
of
the
circuit
board
using tlle
game
screws.
PICTORIAL
3
NOTE:
When
using
hookup
wire
in the
following
steps,
cut the
required
length
of
wire
and
strip
l/4
of. insulation
from
each end.
Connect
one
end
of thefollowingwirestottre
eir_
cuit board.
The
correct
length
is
given
at the
beginning
of each
step.
The
free
ends
of
tlese
wires
will
be
connected
later.
1.
(
2.(
3.(
4.(
5.(
6.(
t.
\
8.(
e.(
10.
(
)5"
)3"
)2"
)
4-t/4"
)4"
)
r-3/4,'
I
L-3/4"
)
3-r/2,,
)2"
)
2-3/4"
LENGTH
FROM
TONE-3
(S-1)
vol-z
(s-1)
vol-1
(s-l)
TONE-1 (S-1)
TONE-2 (S_1)
BATT
+
(S-1)
vol-3
(s_1)
AFC-z (S-1)
rF
-
(s-1)
IF
+
(S-1)
(
)
Referr
Iength
CUT
THE
BELOW. I
TAKING
C,
OF
THE SF
INSULATII
PEEL
OFF
THIN
WIRI
REMOVE
TI
SMALL
WIF
AMOUNTS
(
L
E A D A
ND
SOLDER
12.()
At
w'i
(s.
ou
he
mi
re
lei
co
F-+::i
l
/_---"1
\-f",
\l= JJ
\n*}n
\\./
oi^./
ilVffi
LJ^II
&J
ra/
vt
I@EEEEEEFI
nu*"
n
11.
(
)
Connect
a 4-3f4,'
wire
between
points
AFC-1
(S-1)
to
AFC-I
(S-1)
on
tne
circuit
board.
Position
as
shown.
(
)
Referring
to Detail
3A,
prepare
a
J-t/Z',
length
of shielded
cable as
shown.
12.
( ')
At
oneendofthecable.connecttheinner
wire to AGC
(S-1)
andtheshieldtoGND
(S-1)
of
the
circuit
board. Leave
tlre
other end free.
Be
careful not to
over-
heat the
cable
conductors
since this
may
cause the
inner
insulation to
melt,
resulting
in
a short
circuit.
Grip the
leads
with
pliers
between
the
solder
connection
and the
insulation.
13.
(
)
Remove
l/4t' of insulation from
each
end
of a
9" Iength
of
stranded black
wire.
Twist
the
separate
strands
to-
gether
tightly
at each
end
of
the
wire.
Then
apply
a
small amount
of
solder
to
each
end toh6iTifre
strands
tosether.
(
)
Connect
one end
of
this
g"
black
wire
to
BATT-
on
the
circuit
board
(S-1).
The
other
end
will
be
connected
later.
14.
(
)
RFC-1.
Cut
one lead
length
of a RF
choke
(#45-3b)
to
1",
place
B/4,'
of.
sleeving
over this
lead
and
connect it
to
RFC-I
on
the
circuit
board
(S_1).
Leave
the
other end
free.
(
)
Ctip
off
all
excess
leads
at the
soldered
joints
on
the
foil
side
of
the
circuit
board.
NOTE:
When
mounting
transformers
in the
fol-
lowing
steps,
carefully
align the
pins
of each
transformer
with the
holes
of
the
circuit
board.
The
spacing
of
the
transformer
pins
and
the
holes
of
the
circuit
board
are
such that
when
alisned
properly
ttrey
will mount
easily,
withoutforJing.
15.()
16.()
1?.()
T7.
Install
the
outputtransformer
(#b1-
98) at T?.
Solder
all
5
pins.
T6. Install
the driver
transformer
(#51-97)
at
T6. Solder
all
5
pins.
T3.
Install
one
of
the
IF transformers
(#52-51)
at
T3.
Solder
all
8
pins.
18,
(
)
T4.
Install the
remaining
IF trans-
former
(#52-51)
at T4. Solder
all 8
pins.
19.
(
)
T5.
Install
the
ratio detector
trans-
former
(#53-6)
at TF. Solder
all?pins.
(
)
Check
to
see
that
all the
connections made
on the
circuit
board have
been
soldered.
Set the
board
aside temporarily.
ll
v
t
l
t
i
:
I
;
I
I
I
I
CUT THE
CABLE
ACCORDING
TO
THE DIMENSIONS
BELOW.
PREPARE
EACH END
A5 SHOIVN.
IAKING
CARE
NOT
TO
CUT THE VERY THIN WIRES
OF THE SHIELD
LEAD,
REMOVE
THE
OUTER
INSULATION.
PEEL
OFF THE
FOIL AND
STRAIGHTEN
OUT
THIN WIRES
OF
THE SHIELO
LEAD.
REMOVE
THE
INNER
INSULATION
AND TIVIST
THE
SMALL
IYIRES
OF THE
SHIELO
LEAD.
APPLY
SMALL
AMOUNTS
OF
SOLDER
TO THE ENO
OF THE SHIELO
LEAO AND
THE
INNER
LEAO.
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