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To put
the unit inlo
open lion proceed as follows
:
First
undo
the canvas
cover
and
open
the
meld
doors
to
expose
the
chassis panel
and the b>ttery compartment. Then
cemove the
transmitter-
receiver
chassis by extracting the four screws through the top of the p•nel
and the two
$Crews into
the
sides
of
the
chassis. If the
customers crystals
were avaifable
before shipment, these will
be in
place
in
the
sockets along
the right hand
side of the
chmis.
If the
crystals
arc
separate,
they
~hould
be
placed in
these
sockets,
care
being
taken to
orient
them
so that
the pin
connecting
to the exposed
metal plate of
the holder is located
in
the right
hand,
or
outside hole of
each socket,
this pin being the
ground side.
Make
cc-rtain also that
all
valves arc
in
their
proper
sockets
as indicated
by
the
markings
on the
base
beside
each
socket.
.
Power should
no.,.
be applied to
the chassis before ccplacing it in
the
cast. Either
light
duty
or hc»'Y batteries may be
used
for this purpose, the
connection
to the POWER receptacle being made
by
mans of the appropriite
b>ttery coble
.
.
The microphooe-beadset
assembly
should be plugged
into the
receptacle designated AUDIO
and
the
unit
turned
on
by me•ns
of
the
OFF.ON
switch. The receiver should
now
become operative
and if
the
volume control is
advanced, a signal or
background noise will
be
audible in
the headphones.
Battery
voltage will
be
indicated
on
the meter if
it, switch
is
moved
to the B-VOLTS position. Normally no further
receiver
adjwt-
ments
will be n«cssa.ry,
Now with
the meter switch on
TRANS FIL, pccss the bulton on the
m,crophone.
This
should
operate the reby and a.use a reading to appear on
the
meter.
The
Fil
control should
be adjusted to make the meter pointer fall
on
the red line al 2.t5
volts.
If
the meter switch is now moved to TRANS
"I1JNB,
a
reading
of
approximately
U
ma will
be
observed if the crystal
is not oscillating,
or a
Ycry high
reading if it
is
oscillating.
The
crystal stage
is tuned
by the three small
screwdriver-adjusted
condensers thar•Jocate in a
row
in
the right
hand
side
of
the
chassis.
Thc,e condensers must
be
adjusted
with
tn
insulated
screwdriver
or socket wrench. since the
shafts carry
an r•f
patential
as well
as
the 180 volt
d<_
supply.
Each
of
the thr« condc_nscrs is
associated
with the
cryst1r
socket
immediately
above
it,
which in
turii
is in
circuit
wh(fl the CHANNEL switch
u
set
to the channel number that is
.Jso
stamped beside the cry,til
socket
The
condensers
should
be adjusted
to
a
point just before
the
crystal stops oscillating, as indioted by
a
falling
oi
the meter
reading
to about
I)
ma.
The
adjustment should
not
be
so
clOS<
to thu point that oscillations ace not established
•t
once every
time
the
microphone
button
is pressed.
The value of
the
p-a grid current
(or in
oth,r words
the
m,gnitudc of the oscilfator output) may be measur~d, if
desired, by
plugging
a
d-c
milliamm,t,r
connected
to
a
two-circuit plug
into
the
KEY jack, and
for normal operation should be
approximately 3
ma.
Ndutraliution of the p·• stage is catried out accurately •t the
Factory
before
shipment,
so
ore
should
be taken
that the
setting
of
the
neutralizing
conderlscr
C}I is not
disturbed. The correct
position of this
condenser
usually
will
be
with its
plates slight!)'
less
than half
meshed, and such a
>citing
may
8
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