DRAKE ML-2 User manual

STANDARD
WARRANTY
R.
Le
DRAKE
COMPANY
warrants
each
new
radio
product
manufactured
by
it
to
be
free
from
defective
material
and
workmanship
and
agrees
to
remedy
any
such
defect
or
to
furnish
a
new
part
in
exchange
for
any
part
of
any
unit
of
its
manufacture
which
under
normal
installation,
use,
and
service
discloses
such
defect,
provided
the
unit
is
de-
livered
by
the
owner
to us
or
to
our
authorized
radio
dealer
or
wholesaler
from
whom
purchased,
intact,
for our
examination,
with
all
transportation
charges
prepaid
to
our
factory,
within
ninety
days
from
the
date
of
sale
to
original
purchaser
and
provided
that
such
examination
discloses
in
our
judgement
that
it
is
thus
defective.
Should
a
malfunction
be
suspected,
write
in
detail
to
our
Service
Department
for
suggestions
concerning
the
operation,
repair
or
return
of
your
unit
if
it
should
prove
necessarye
This
warranty
does
not
extend
to
any
of
our
radio
products
which
have
been
subjected
to
misuse,
neglect,
accident,
incorrect
wiring
not
our
own,
improper
installation,
or
to
use
in
violation
of
instructions
furnished
by
us,
nor
extend
to
units
which
have been
repaired
or
altered
outside
our
factory,
nor
in
cases
where
the
serial
number
thereof
has
been
removed,
defaced
or
changed,
nor
to
units
used
with
accessories
not
manufactured
or
recommended
by
us.
Any
part
of
a
unit
approved
for
remedy
or
exchange
hereunder
will
be
remedied
or
exchanged
by
the
authorized
radio
dealer
or
wholesaler
without
charge
to
the
owner.
This
warranty
is
in
lieu
of
all
other
warranties
expressed
or
implied
and
no
representative
or
person
is
authorized
to
assume
for
us
any
other
liability
in
connection
with
the
sale
of
our
radio
products.
The
Re
Le
DRAKE
COMPANY
reserves
the
right
to
make
any
improvements
to
its
products
which
it
may
deem
desirable
without
obligating
itself
to
install
such
improvements
in
its
previously
manufactured
products.
R.
Le
DRAKE
COMPANY
MIAMISBURG,
OHIO
45342
@

ML=2
CORRECTIONS
&
PART
CHANGES
In
some
ML=2's
the
following
parts
have
been
changed
as
noted
below,
In
each
case
these
parts
are
electrically
interchangeable,
2S8C 460
28C458
28C741
181555
Diode 2007 or 207 "
Diode SRIEM1
Diode SRIEM8
changed to
28C838
28C 945
280319
18953
RD-7A-M
Fe14A
F-14D
ML-2 TRANSMIT. & RECEIVE CRYSTALS
Crystals
for
your
ML-2
are
available
from
the
R. L.
Drake
Company
at
a
cost
of
$5.00
per
crystal.
Prior
authorization
must
be
obtained
from
the
R.
L.
Drake
Company
before
returning
crystals
for
any
reason.
Servial hte - 10 932
R, L, Drake Company
September 21, 1971
orca

ML-2
MARKER
LUXURY
TRANSCEIVER
PAGE
1.
GENERAL
DESCRIPTION
...e..seeeee
seseoesesees
1
FEATURES.....
PEPE NNNODeE
Qa
oO 3
g
o ~
YN
Hee
&
De
e Q
©
& <
o
5
2. INSTALLATION..... bbe cece eee ee cree cess erescesees O
UNPACKING .......-- outeees
LOCATION .cscecccccccccseecsccsere
NNN
NVYNYD
NOOhwWONne
VERTICAL ANTENNAS........- see
POWER REQUIREMENTS ...ssseeceeeoeees
SPEAKER AND HEADPHONE REQUIREMENTS . see
MICROPHONE REQUIREMENTS .+.sssssesesecsseceusesecs
w CONTROL FUNCTIONS ......... teeeee avec eeceee 5
FRONT PANEL CONTROLS ..ccscecccscccccecccesreereres
On-Off Switch ..
Volume......
Squelch.....
Re ee
OwWWWwWw
bodPE
INTERNAL CONTROLS ....-ssecccecccccrcoccecesiovese
Deviation Controls ......eeeeeeee
Transmitter Frequency Adjustment ...
Receiver Frequency Adjustment ....
S-Meter Sensitivity Adjustment ........ .
Relative RF Output Meter Adjustment ......
NNNNNN
arkrwondre
Ce eeeeeerone
coccenee
WWW
ww
oo
> CRYSTAL ORDERING INFORMATION.....-.e0002 7
5. TROUBLE SHOOTING. cccccsvccccersccevcscecseceee B
6.
SCHEMATIC
FOR
ML-2......
eee
eeecceeee
ee
eeeee
Fold
Out

1.1
1.2
1.2
vl
GENERAL
FEATURES
DESCRIPTION
The
ML-2
is
a
2
meter
VHF
-
FM
Transceiver
with
a
capacity
for
12
channels
and
will
operate
from
either
120
VAC
50
-
60
Hz
or
13.5
VDC.
SPECIFICATIONS.
GENERAL
Frequency Coverage:
Number of Channels:
144 - 148 MHz
Completely transistorized with a 6360 PA tube.
12 channels,
3 supplied.
Channel 1 Channel 2 Channel 3
Receive: 146.94 MHz Sreteceas= 146.76 MHz
Transmit: 146.34 MHz ARS SSeS 146.34 MHz
Simplex: —if| ---------- 146.94 MHz =| ----------
Modulation: Frequency Modulation
Transmitter Control:
Power Drain:
Push-to-talk
A.C, | D.C.
“Receive:
6
watts
0.5
amps
Transmit:
50
watts
4.0
amps
Power
Source:
A.C.
120
Volts,
50
-
60
Hz.
D.C. 13.5 Volts, + 10%
Dimensions;
Weight:
Accessories Supplied:
7-7/8"
W
x
2-3/4"
H
x
10-1/4"
D
8-1/4 pounds.
-Antenna;
Dynamic Microphone,
Antenna Connector Plug,
AC/DC Power Cord,
Speaker Plug,
Mobile Mounting Bracket.
Page lL.

1.2.2
1.2.3
RECEIVER
Receiver Circuit:
ist 1.F. Frequency:
2nd I.F. Frequency:
Antenna Input Impedance:
Sensitivity:
Spurious Sensitivity:
Audio Output:
TRANSMITTER
RF Output Power:
Frequency Deviation:
Frequency Stability:
Spurious Radiation:
Completely transistorized crystal controlled
double conversion superheterodyne .
10.7 MHz
455 kHz
50 to 75 ohms
0.5 microvolt or less for 20 dB quieting.
1 microvolt or less (30 dB S + N/N ratio
at 10 kHz deviation with 1 kHz modulation.
Greater than - 60 dB
0.5 watt at 10% or less distortion
10 watts conservative
Adjustable to 15 kHz maximum.
Factory set to $ kHz
+ .001% or less.
Greater than - 80 dB below carrier.
Page 2.
0

2. INSTALLATION
2.4
UNPACKING
@
Carefully
remove
the
Marker
Luxury
Transceiver
from
its
carton
and
examine
it
closely
for
signs
of
shipping
damage.
Should
any
be
apparent,
notify
the
delivering
carrier
immediately
stating
the
full
extent
of
the
damage.
Fill
Out
and mail
the
enclosed
registration
card
so
your
warranty
will
be
effec-
tive.
Save
the
packing
material.
You
may
need
it
later
for
reshipment
or
storage.
Inspect the packing material closely before putting it away to be sure you
have not overlooked the accessories packed with the unit.
2.2 LOCATION _
In general, the location of the Marker Luxury is not critical. However,
care
should
be
taken
to
insure
that
space
is
provided
around
the
unit
to
allow
adequate
air
circulation.
Extremely
hot
locations,
such
as
near
radiators
or
heating
units,
should
be
avoided.
DO
NOT
cover
the
top
of
the
unit
with
books,
papers
or
pieces
of
equipment
or
overheating
may
result.
2.3
ANTENNA
REQUIREMENTS
The
Marker
Luxury
Transceiver
is
designed
for
use
with
antennas
resonant
~
on the
operating
frequency
and
having
an
impedance
of
50
ohms.
The
e@
antenna
we
supply
must
be
adjusted
to
the
operating
frequency.
Tools
and
a
chart
are
supplied
for
this
adjustment.
The
antenna
can
be
adjusted
most
accurately
with
a
Drake
WV-4
Wattmeter
in
the
transmission
line.
With
the
WV-4
Wattmeter
in
the
line,
adjust
the
length
of
the
antenna
for
minimum
reverse
power
reading.
2.4
VERTICAL
ANTENNAS
Vertical
antennas
without
their
ground
planes should
not
be
used
with
the
ML-2.
Omission
of
the
ground
plane
causes
excessive
RF
ground
current
on
the
ML~2
case
resulting
in
RF
feedback
and
reports
of
hum
on
the
ML-2
transmitted
signal.
2.5
POWER
REQUIREMENTS
The
Marker
Luxury
Transceiver
is
factory
wired
for
use
with
120
volts
50
-
60
Hz
and
13.5
volts
DC.
For
use
on
120
volts,
insert
the
power
connector
with
the
line
cord
attached,
into
the
power
plug
on
the
rear
of
the
transceiver.
For
use
with
13.5
volts
DC,
insert
the
power
connector
with
the
red
and
black
wires
attached,
into the
power
plug
on
the
rear
of
the
transceiver.
The
red
wire
is
the
positive
lead
and
the
black
wire
negative.
The
fuse
in
the
positive
lead
has
a
value
of
6
amperes.
The
120
volt
fuse
has
a
value
of
2
amperes.
Page 3.

2.6
2.7
SPEAKER AND HEADPHONE REQUIREMENTS
The
Marker
Luxury
Transceiver
has
a
built-in
speaker.
An
external
8
ohm
headphone.
or
speaker
may
be
plugged
into
the
miniature
phone
jack
on
the
rear
of
the
transceiver
chassis
next
to
the
R.F.
output
connector.
Plugging
an
external
speaker
or
headphone
into
this
jack
turns
off
the
built-in
speaker.
MICROPHONE REQUIREMENTS
A 500 ohm dynamic microphone with a push-to-talk switch is supplied with
the Marker Luxury Transceiver. A carbon microphone may be used with the
transceiver and connection to the microphone plug is shown in the
schematic.
Page 4.

3.1
3.1.1
3.1.2
3.1.3
3.1.4
3.2
3.2.1
3.2.2
3.2 -3
CONTROL FUNCTIONS
FRONT
PANEL
CONTROLS
ON-OFF SWITCH
The ON-OFF switch is a toggle switch in the left bottom of the front panel
and turns the transceiver on when the switch lever is in the up position.
VOLUME
The AUDIO GAIN control is the inner knob of the concentric controls at the
left top of the front panel. Clockwise rotation of this control increases
audio gain.
SQUELCH
The SQUELCH control is the outer knob of the left top concentric front panel
controls. Clockwise rotation increases the signal level required to defeat
the squelch circuit and allow reception.
CHANNEL SELECTOR
The knob in the center of the front panel selects one of twelve possible
transmit and receive crystal pairs.
INTERNAL CONTROLS
DEVIATION CONTROL
With
the
cover
removed
and
front
panel
facing
you,
the
transmitter
circuit
board
is
visible
looking
into
the top
of
the
transceiver.
The
final
amplifier
tube
and
relay
are
also
exposed.
The
deviation
control
is
the
trimmer
resistor
at
the
right
rear
of
the
transmitter
circuit
board
.
This
control
is
set
by
ourselves
to
5
kHz
deviation.
Greater
deviation
than
this
can
be
obtained
by
counter-clockwise
rotation
of
this
control.
.Use
an
insulated
screwdriver
for
this
adjustment.
Accidental
connection
between
the
deviation
control
and
ground
will
destroy
IC
201.
TRANSMITTER
FREQUENCY
ADJUSTMENT
With
the
front
panel
facing
you
and
looking
into
the
top
of
the
transceiver,
the
transmitter
crystals
correspond
to
the
channel
numbers
and
are
numbered
right
to
left,
1
through
12.
There
are
two
banks
of
trimmer
capacitors
for
frequency
adjustment.
The
row
closest
to
the
front
panel
adjusts
even
num-
bered
crystals
right
to
left,
2
through
12.
The
row
next
to
the
sockets
adjust
odd
numbered
crystals
right
to
left,
1
through
11.
RECEIVER
FREQUENCY
ADJUSTMENT
With
the
front
panel
facing
you
and
looking
into
the
bottom
of
the
transceiver,
the
receiver
crystals
correspond
to
the
channel
numbers
and
are
numbered
right
to
left,
1
through
12.
There
are
two
banks
of
trimmer
inductors
for
fre-
Page 5.

3.2
3.2
“4
5
quency
adjustment.
The
row
closest
to
the
front
panel
adjusts
odd
numbered
crystals
right
to
left,
1
through
11.
The
row
next
to
the
crystal
sockets
adjust
even
numbered
crystals
right
to
left,
2
through
12.
The
slugs
are
anchored
with
wax.
Before
adjusting
the
slugs,
carefully
melt
the
wax out of
the coil.
The
discriminator
output
for
setting
the
receiver
frequency
is
available
at
a
terminal
lug
on
the
receiver
circuit
board.
With
the
front
panel
facing
you
and
the
ML-2
upside
down,
the
discriminator
terminal
is
the
far
right
lug
on the
circuit
board
edge
closest
to
the
front
panel.
This
lug
has
nothing
connected
to
it.
Ground
for
a
voltmeter
connected
to
this
lug
is
most
convenient
at
the
heat
sink
of
the
audio
output
transistors
near
the
discriminator
terminal.
Note
that
all
circuit
board
grounds
are
NOT
connected
to
the
ML-2
chassis.
S-MEJER
SENSITIVITY
ADJUSTMENT
The
S-METER
response
sensitivity
is
determined
by
the
trim
pot
at
the
right
rear
of
the
receiver
circuit
board.
The
receiver
board
is
the
bottom
front
board
in
the
transceiver.
RELATIVE
RF_
OUTPUT
METER
ADJUSTMENT
The
RELATIVE
RF
OUTPUT
METER
sensitivity
is
determined
by
the
trim pot
at
the
right
rear
of
the
power
supply
board.
The
power
supply
board
is
the
bottom
rear
board
in
the
transceiver.
Page 6.

CRYSTAL ORDERING INFORMATION
Accessory channel crystals may be ordered from the R. L. Drake Company.
To order, specify the desired receive and transmitting frequency.
If you desire to order crystals from another source, the following infor-
mation should accompany your order.
TRANSMIT CRYSTALS:
Fundamental
mode
parallel
resonant
with
30
pF
load
capacity
in
HC-25/U
holder.
Divide
transmit
frequency
by
12 to
obtain
crystal
frequency.
RECEIVE CRYSTALS:
Overtone mode series resonant in HC-25/U holder.
Subtract
receive
frequency
by
10.694
MHz
and
divide
by
3
to
obtain
crystal frequency.
Page 7.
-
ae

TROUBLE SHOOTING _
Careful
consideration
has
been
given
to
the
design
and
testing
of
the
ML-2
to
keeping
maintenance
problems
to
a
minimum.
If
you
experience
difficulty,
we
recommend
that
you
return
the
unit
to
your
Drake
dealer
or
write
direct
to
our
Customer
Service
Department
describing
your
problem
in
detail.
DO
NOT
RETURN
EQUIPMENT
TO
THE
FACTORY
WITHOUT
PRIOR
AUTHORIZATION.
k
|
Page 8.
ey

MUL-2
ELECTRICAL
PARTS
e
A.
POWER
SUPPLY.
R301
Resistor
R302
Resistor
R303
Resistor
R304
Resistor
R305
Resistor
R306,307
Resistors
R308
Resistor
C301
Capacitor
302
Capacitor
C303,304,310
Capacitors
C305
Capacitor
C306,307
Capacitors
308,309
Capacitors
C311,312,313
Capacitors
C314
Capacitor
Q301,302
,303
Transistors
Q304
Transistor
D301,302
,306
Diodes
D303
,304
Diodes
D305
Diode
PL301
Pilot
Lamp
8301
Switch
T301
Transformer
J301
Connector,
Plug
P301
Connector,
Socket
P302
Connector,
Socket
F301
Fuse
F302
Fuse
Page 9.
300
-10
5
1K
330
470
470
1000 uf
100 uf
47 uf
-047 uf
-005
/
.01
60 uf
-001 uf
-01 uf
2
SB
337
2
8C
460
SEIEM 1
SEIEM 8
MZ207
18V
3w
3w
3w WW
1/aw
1/faw
1/aw
1/2 w
25
V
Electrolytic
16
V
Electrolytic
16
V
Electrolytic
400
V
Oil
500
V
Ceramic
160
V
Electrolytic
50
V
Ceramic
500
V
Ceramic
AC
Power
DPST
Power
12
P
Power
12
PDC
12
PAC
2 amp
6 amp
—_—

ML-2
ELECTRICAL
PARTS
B.
TRANSMITTER
R201,205,207,208,216,
219,222,228
* R225
R202 ,215
R203
R204
R206
R210
R213,214,220,223
,227
R217
R218
R221,224
R226
R231
R209
R211
R229,212
R230
R232
VR201, 202
C202
,219,237,250,260,261,262,
263,252,
253,254,255
204,212,210
C213
,223,225,230,235,236,238,
239,242
,231,256,257
C214,215
C216 ,217
C218
220,233,241
C221,228
C222
C224
C226 ,229
C227
C232 ,249
C234
C243 ,244
C257
258
C259
C245 ,246
Resistors
Resistor
Resistors
Resistor
Resistor
Resistor
Resistor
Resistors
Resistor
Resistor
Resistors
Resistor
Resistor
Resistor
Resistor
Resistors
Resistor
Resistor
Resistors
Capacitors
Capacitors
Capacitors
Capacitors
Capacitors
Capacitor
Capacitors
Capacitors
Capacitor
Capacitor
Capacitors
Capacitor
Capacitors
Capacitor
Capacitors
Capacitor
Capacitor
Capacitor
Capacitors
Page 10.
1K Ohms
100 Ohms
47K
330
Ohms
100 K or 220K
33K
3.3K
10K
82 K
4.7K
150
Ohms
10
Ohms
1.5K
470 Ohms
330 Ohms
10K
20K
12K
10 K Variable
-01 W Ceramic
.1 u Ceramic or Mylar
-001 W Ceramic
500 pf Ceramic
200 pf Ceramic
60 pf Ceramic
5 pf Ceramic
80 pf Ceramic
300 pf Ceramic
15 pf Ceramic
2 pf Ceramic
20 pf Ceramic
1 pf Ceramic
10 pf Ceramic
.001 or .005 W Ceramic
7.5 pf N750
33
pf
Ceramic
25 pf Ceramic
50 pf Ceramic
I

B.
_TRANSMITTER
C247
C248,C264
thru
275
C201,203,211
C205
,207,208
C206
C209
C240
VC201
thru
214
VG215
Q201,202,203
Q204
Q205
1201
D201
D202
D203
v201
F201
J201
CH201
1201
thru
205
1LC201
thru
209
ML-2
ELECTRICAL
PART
Capacitor
Capacitors
Capacitors
Capaciters
Capacitor
Capacitor
Capacitor
Capacitors
,
Var.
Capacitor,
Var.
Transistors
Transistor
Transistor
1c
Diode
Diode
Diode
Tube
L.P.
Filter
Jack,
Mic.
Choke,
Iron
80
mH
Choke
,
RF
Coil,
RF
Page 11.
Ss
100
pf
Ceramic
7
pf
Ceramic
«5
uf 10
V
Alum.
4.7
W
16V
Elect.
10W
33
W
100
W
50 pf
20 pf x 2
280460
28C717
280741
1A1201
1N60
MZ207
$C20
6360
LPF
4-pin

ML-2
ELECTRICAL
PARTS
C.
RECEIVER
_
R101,
102,
116,115,133
R103,
126,130,150,158
R104,
105,
122,134,141,149
R106,
107,109,112,
114,
145
R108
111,
124,142,147,151,
154,159,
118,and
180
thru
191
R110,121
R113
R119,123,140
R125,143,160
R127,128,135,137,153
R129,136,144,155,161
R131
R132
R138,139
R148
R152,120,117,157
R156
R146
VR101
VR102
C101,102A and D,107,108,109,113,
110,133,134,171,142,172,135,256,
257, 111
©103,104,112,116,118
ci21
106,259
C105
C169 ,120
C115,117,119,122,124,125,
129,130,127, 126,140,141,172,
149,128,158,143,150,166,167,164,
144,
C123
C135
C134,136,138,139,165
C145 ,146
C147 ,153,163
cl48
C258
Page 12,
Resistors
Resistors
Resistors
Resistors
Resistors
Resistors
Resistor
Resistors
Resistors
Resistors
Resistors
Resistor
Resistor
Resistor
Resistor
Resistors
Resistor
Resistor
Resistor, Var.
Resistor, Var.
Capacitors
Capacitors
Capacitor
Capacitors
Capacitor
Capacitors
Capacitors
Capacitor
Capacitor
Capacitors
Capacitors
Capacitors
Capacitor
Capacitor
100K
22K
4.7K
100 u
1Ku
330-u
620 u
33 K
470u
47K
10K
470K
220K
82K
10u
3.3K
1.5.K
50u
10K x 2
10K x 2 (
-001
1.0 pf
25 pt
25 pf
3.0 pf
2.0 pf
Olu
10 pf
200 pf
-04u
330 pf
100 pé
-005 u y
33 pf

ML-2
ELECTRICAL
PARTS
csi
152,156
C154
C155,159
C157
C161
Q101,103,105,106
Q102
Q108,109,107
Q110,111,112,113,114
Q104
Q115,116
1C101
D101,102,103,104,107,108,109,110
D105,
106
F101
x101
T101
T102
y101
SP101
Capacitor, Var.
Capacitor,
Capacitor
Capacitor
Capacitor
Capacitors
Capacitor
Capacitors
Capacitor
Capacitor
Transistors
Transistor
Transistors
Transistors
Transistor
Transistors
Ic.
Diode
Diode
Filter
Crystal
Transformer
Transformer
Jack, Speaker
Speaker
Page 13.
50 pf
500 pf
47u
Su
150 pf
4.7u
1.0u
-lu
10u
47 u
28K19/33
3SK22
28C460
28C458
280717
2SB77
1A1201
1N60
181555 or IS953
455 kHz
10.245 MHz
10K:
2
K
input
400 ohm : 8 ohm output
8 ohm

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