-
PHILCO
Q0.1/.a.PAT. or,
Service Bulletin~ No.
191
Model 45
Philco Model 45 is a six tube receiver operating on alternating current and capable of receiving
either sta ndard and police broadcasts between 540 and 1720 kilocycles, or short-wave
stationS:~between
4.2 and 13 megacycles . The left hand side of the dial is calibrated in kilocycles for standard reception
and the right in megacycles
for short-wave stations. A two-position switch changes reception from
standard to short -waves.
Mod~l 45 uses a type 6-A-7 detector-oscillator, two type 39-44 I. F. Tubes, type 75 2d detector,
type 42 output tube, and type 80 rectifier. The power consumption is 65 watts. The intermediate
frequency is 460 K.C.
Tube Socket Voltages
Det. 1st
2d
2d
Out-
CIRCUIT
Osc.
IF IF
Del.
put
Rect.
--
-- -- -- --
Type Tube
6A7
39-44
39-44
75 42 80
- - --
-- -- - -
Filament (F to F) ...
6.3 6.3 6.3 6.3
6.3
5.0
- - --
--
-- --
Plate (P to K) ....
260 255
255
175 250 335
--
--
--
--
--
Gl-35
Screen Grid (SG to
K/ ... . . 02-135 75
75
... 260
03&5-85
-- - - -- - - --
Cathode (K to F) ....
4.2 3.8 3.8
0 0
...
The above te.,ts were made with an AC voltmeter for filament voltages and a
high resistance DC voltmeter-for all others. Dial at 550 KC, volume control at
maximum. Test made with
test prods applied to socket terminals underneath
chassis. Line voltage 115.
.8.D
RECTIFIER
~
~
ill
DET. DSC.
Gs&. G1
--
'
~
S<
Pe •
-- .,.
39-44
1
11
IF.
Fig. 1-Tube Socket Layout (underside )
Power Transformer Voltages
Terminals Volts Circuit
1-2
120
Primary
3-4 5.0 Fil. of 80
5-7
680
Plates of 80
8- 10 6.3
Filaments
6
Center of 5-7
9
Center of 8- 10
fREOUEJ4CY·IWID TONE
$WITCH CONTROL
Flg.·2-Chasals Top View
Color
Leads
White
Blue
Yellow
Black
Yellow-Gr een tr.
Black-Yellow tr.
---42
80
;,,- ~:=;::::;l-75
Adjusting Compensating Condensers
For adjustment of compensating (padding) condensers in
model 45, an accurately calibrated signal generator and a
special insulated padding wrench are needed. We suggest the
Philco Model 024 Signal Generator or the 048 Tester which
includes a similar instrument.
The chassis must be removed from cabinet in order to make
all adjustments .
Adjustments are made in the following order-
ADJUSTMENT OF THE INTERMEDIATE FRE-
QUENCY-Remove the grid clip from the type 6A7 tube
and connect the "ANT" output terminal of the signal gen-
erator to the grid
cap of the tube. Connect the "GND"
terminal of the signal generator to the "GND" terminal of
the receiver chassis.
Connect the output meter to the primary terminals of the
outpu t transformer. Set the signal generato r at 460 K.C. (the
intermediate frequency of Model 45)
and with the receiver
and signal generator turned on, the wave band switch at left
and dial
at 600 K.C., adjust each of the I. F. compensating
condensers in turn, to give maximum response in the output
of the receiver. The three pairs of
I. F. compensating con-
densers are located one pair at the top of each of the three
I. F.
transformer shields. These are the three metal "cans" near
the rear of the chassis. Each of the transformers has
a dual
compensating condenser mounted at its top, and accessible
thru a hole in the top of the coil shield. In the dual compensa-
tors, the Primary circuit is adjusted by turning the screw; the
Secondary circuit is adjusted by turning the hex-head nut.
ADJUSTMENT OF THE WA VE TRAP-Replace the
grid clip upon the Detector-Oscillator tube (Type 6A7).
Connect the output leads from the signal generator directly
to the antenna and ground terminals of the receiver. Set the
Wave-Band Switch of the receiver to the standard broadcast
band (left hand position) and
the Station Selector at the lQ;w
frequency (540 K.C .) end. Adjust the Wave Trap condenser
to give MINIMUM response to a 460 K.C. signal from the
signal generator. The Wave Trap
CD is located at rear and
underneath the chassis, and is shown in Figure 4. It is
reached from the rear of the chassis, by insert ing the fibre
wrench thru the hole near right-hand rear corner of chassis.
DETECTOR, AND OSCILLATOR
"HIGH" '1\.ND "LOW"
FREQUENCY
ADJUSTME~TS-The "ante nna" and
"oscillator H. F." compensators are located on top of the
tuning condenser assembly, reached from above.
Set the signal generator at 1500 K.C., tune in this signal on
the set and adjust the antenna compensator
G) (nearest tuning
control) to give maximum reading in the output meter.
Next adjust the oscillator H. F. condenser
@ (located on
the other section of tuning condenser) to maximum reading.
l<'inally set the signal generator at 600, tune in t.his signal
and_ adjust the
oscills.'tor "L. F. condenser", located under-
neat}!. chassis (@ in Fig. 4) to maximum reading . This
adjust ment is reached thru
,the hole in top of chassis, between
the two electrolytic condensers (left hand end of chassis when
facing rear). '
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