Philco 700 Service Manual

.r@.,
PHILCO
TRANSITONE
SERVICE BROADCAST
MAY,
1934
MODEL
7OO
RECBIVER
,-f-.ru
latest Philco
development
in
single-unit automobile radio
is the
new
Model
700.
This
Receiver
is
compact,
I
easier
to install than
ever before and
will give
exceptional performance.
It
is a
six-tube
super-heterodyne
with a
genuine
full-size Philco electro-dynamic speaker-the
same
type that
is
used
in
many
of
the larger home
radio
Receivers.
It
has
remarkable sensitivity,
a
three-section
tuning
condenser, giv-
ing improved
selectivity-wonderful
tone,
with a
three-point tone control, and inherently
quiet circuits.
Interference
filters
in
the "A"
lead and
in
the
pilot light
lead
greatly simplify motor
interference
suppression.
In
most
installa-
tions standard suppression
is
sufficient.
Added
to
this, the
ease
of installation
characteristic
of this model (only
one
unit to install-one
lead
to
the
an-
tenna, one lead
to
the ammeter) and the
convenient, attractive airplane
type
steering
column control,
which makes this
model universal
in its
application, are
additional
features
of the Model
700
which appeal
to
both the
dealer
and
the
public.
I.
F.
TRANSFORMER
AND
PADDERS
The
new
style
I.
F. transformer
complete
with
padders
is
used
in
the Model
700.
The
padders
are placed
in
the top
of
the
shield
can
one above the other.
The
primary
padder
is
adjusted
by
means
of the
screw
slot,
accessible
through
the hole
in
the top of the
shield
can.
The secondary padder is adjusted
by
means
of
the
small hex
nut,
also
accessible
through the
hole
in the
top
of
the
shield.
(See
Figs.
1
and 2.)
The coil windings
terminate
in
Ieads instead
of
ter-
minals
or
lugs.
The color
scheme
of
the
leads
is given
in
Fig.
l.
If
replacements are ever
necessary, replace the
entire
coil
assembly
32-1329
for
the
first
I.
F.
stage and32-1237
for the
second
I.
F. stage. Neither the coil nor the
pad-
ders
will
be
furnished
separately. Order only by
the
above numbers.
PRIiARYPAOOER
SE@NORPADOR
SCN€W
ADJUTNEfr
TUT
AN!5IN$T
1st
I.
F.
Transformer
2nd
I.
F.
TransJormer
32-1329
32-1237
Fro.
1
MODEL
7OO
ADJUSTMENTS
All
adjustments
have been carefully
checked
at
the
factory.
If,
however,
it
is
found
necessary
to
readjust
the padding
condensers,
this
procedure
must be followed
carefully. Do
not
atternpt to make
any
adjustments
until
the
procedure
is clearly
understood
or
without
the
use
of a
good oscillator or signal generator and output
meter. The Philco
Set
Tester 048 is
highly
recommended
for this
procedure
and
for all
service work.
The
Receiver must be
connected
to a
six-volt
storage
battery and turned on
for operation.
It
is
assumed
that
tubes
have been checked and
that the
Receiver
is
in
gcod condiiion except
for
the padding
adjustments.
'
-,
Remove
the
speaker
lid
from the Receiver.
Remove
""he
grid cap terminal from the
77
tube
(for
location
see
Fig.
2).
Set
up the
signai generator and adjust
it
to
exactly
260
K.
C.
Connect
the generator lead to
the
grid
cap of
the 77
tube.
(See Fig.
2.)
The output meter must
be
connected.
The
Receiver volume control
must be turned on
to
approximately
full
volume
and the attenuator
in
the gen-
erator set
for
a half-scale reading
of
the
output
meter.
The padders @
and
6
are adjusted
first (Figs. 2
and
3).
Turn theadjusting screw
@
all
the
way
in.
A
metal
screwdriver
can
be used
for
this.
Then,
with
generator
attenuator set
so
there
is
approximately half-scale
read-
ing, adjust the
nut
@)
with a fibre
wrench
for
the
max!
mum
reading on the
output
meter.
Then adjust the screw
6
for maximum
reading on
the
meter. This
adjustment
is
critical.
Note the
maximum
reading obtainable and then
turn
the screw
in
again
and
readjust,
just bringing
the adjustment up to the maximum
reading. Do not
pass
it
and then back
off.
Repeat
tle
above procedure
with
the
condensers
@
and
@.
After
padding the first
I.
F.
stage, remove
the
gen-
erator lead
from the 77
tube and reconnect
the grid
lead
fa the77 tube. Set the generator
to
1600
K.
C.
and then
connect
the generator lead
to
the
antenna lead.
fhere
are
four
holes
in line,
one
in
each
of
the sections
!
--
!-__