Philco 38-116 Reference manual

• • • • • • • • rrfli,d,d_ 38-116,CJJdL121
SERVICE
RADI0 BULLETIN NO. 286 for members of MANUFACTURERS SERVICE
SPECIFICATIONS
TYPE OF CIRCUIT: Model 38-116, code 121 employs a fifteen
tube A.C. operated superheterodyne circuit with a spread-band dial
having five tuning ranges covering a frequ ency range from 530 K.C.
to 18.2 M.C.
Incorporated in this model are design features such as: magneti c
tuning control on each tuning range; automatic volume control;
treble-selectivity expander unit in th e intermediate frequency circuit;
audio bass compensation; acoustic clarifiers to eliminate cabinet
resonance ; special push-pull audio output circuit using 6L6G beam
tubes, and the Philco automatic tuning mechanism.
POWER SUPPLY: Voltage
115
115
Frequency
Cycles
50 to 60
25 to 40
Power
Consumption
165 watts
165 watts
Different transformers are requir ed for operation on the voltages
and frequencies listed above. The part numbers for these trans-
formers are listed on page 4. A special transformer for operation on
eit her 115or230volt-50to 60cycleA.C. powercircuitcan be obtained.
This transformer is provided with a plug and socket for selection
of either voltage rating. Place the plug with arrow pointing toward
voltage being used.
INTERMEDIATE FREQUENCY: 470 K.C.
FREQUENCY RANGES: Range One 530 to 1600 K.C.
Two 1.58 to 4.75 M.C.
Three 4.7 to 7.4 M.C.
four 7.35 to 11.6 M.C.
Five 11.5 to 18.2 M.C.
UNDISTORTED OUTPUT: 15 watts .
PHILCO TUBES USED: 6K7 G R.F.; 6L7G Mixer; 6A8G Oscil-
lator ; 6N7G Oscillator contro l; two 6K7G I. F.; 6K7G 2nd
Detector Magnetic tuning amplifier; two 6J5G discriminator;
6JSG A. V. C.; 6R7G 1st audio; 6JSG audio driver; two 6L6G
audio output, and one 5X4G rectifier.
TONE CONTROLS: Two---,---1.High audio-frequency tone \'ari ed
by Treble-Selectivity control.
2. Low audio-frequency tone varied by " Bass Tone Control,"
in the volume control circuit.
PHILCO SPEAKERS USED: One type "W4" with three acoustic
clarifiers .
CABINET: Type XX .
SERVICE NOTES
For reference between illustrations, Parts List, and for replace-
ment of parts, the various diagrams in this bulletin are marked with
"circled numbers" indicating a particular part.
Physical views of the R. F . and I. F. transformers and the range
switch sections are shown on pages 2 and 3. Each part is marked
with the corresponding schematic diagram circled number.
The leads and lugs of the R. F. and I. F. transformers are either
numbered or the color of the wire marked to indicate the connecting
point in the circuit diagram, which is also correspondingly mark ed.
Range switch lugs are marked with a letter and number-example
(A2)-indicating the connecting point in the circuit diagram.
Speaker wiring is shown in Fig. 3 and the power transformer wire
colors are marked on the schematic diagram.
A PHU.CO Service Plan
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DISCR !M!NATOR
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Fill.. 1. Underside View of Chassis showinll. Socket Voltages
The voltages indicated by th e arrows were measured with a Philco 026 Circuit
Tester, which contains a sensitive voltmeter. Line voltage 115 A. C.- Volume
control minimum-Dial set at point where no signal is present-Range Switch
in broadcast position .
Automatic Tuning Mechanism
Service Data
Service data and a complete parts list for the Automatic Tuning
Mechanism of this receiv er will be found in Service Bulletin 273.
There are four automatic dial parts, however, which differ from those
shown in bulletin 273. These parts are marked with an asterisk on
page 4 of this bulletin .
. Aerial Connections
To obtain the full advantage of the sensitivity of this receiver the
Philco High Efficiency Aerial supplied with the instrument must
be used. Connect th e aerial as follows:
The aerial terminal panel located on the rear of the chassis, con-
tains three terminals marked "Red," "Blk" and "Gnd". Connect
the red and black wires of the aerial lead in (Transmission Line) to
th e "Red" and "Blk" terminals respectively. Connect the "Gnd"
terminal to a good ground source. If a temporary aerial is used,
connect it to the "Red" terminal.
Copyright 1937, Philc o Radio & Television Corporation
philcoradio.com

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SPEAKER 50 CKET
TOP VIEW
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Fig. 3. Speaker Wiring
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Fig. l. Underside View of Chassis
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@)Ir EXPANDER UNIT @DISCRIMINATOR TRANS
Fig. 4. I. F. Transformer Connections
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philcoradio.com

No. 288 PBILCO lenrice Balletin Pap3
-I.F.: 470 K.C. ,/ · '@TUN ING CO NDENSER -------- ·-···---- -- ·-7··-·- ----
~ l.f . EXPANDER UNIT -----·-·7
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-
Flat, 5. Schem atic Diagram Model 38-116, Code t:U
philcoradio.com

Page 4 PHILCO Service Bulletin No.Z81
REPLACEMENT PARTS-Models 38-116, Code lZl
Schem.
No. Dnerlptlon Pan
No.
1 Ant. Trans . (Range I) . 32-3208
2 Ant . Trana . (Range 2) .. 32-2146
3 Ant . Trans. (Range 3) . 32-2183
4 Ant. Trans. (Range 4) .. 32-2185
5 Ant. Trana. (Range 5). 32-2175
6 Resistor (51,000----½ watt ) .. 33-351339
7 Condenser (0.5 mf. tubular ). . 30-4444
8 Compensator (Range I & 2 Ant .). 31-6093
9 Compenaator (3, 4 & 5 Ant.)... 31-6112
10 Condenser (.05 ml. tubular) ... 30-4123
11 Coodenaer (600 mmf. miea) ... 30-1049
12 Resistor (I meg. ½ watt ) ........... 33-510339
13 R,oi,to r (400ohm• I watt wire wound). 33-1211
14 Condenser (.05 ml. tubular ) . .... 30-4444
15 Resistor (10,000 ohms ½ watt) . 33 310339
16 R. F. Trans. (Range I) . 32-2105
17 R. F. Trans. (Range 2) . 32-2147
18 R. F. Tran s. (Range 3) . 32-2177
19 R. F. Trans . (Range 4). 32-2178
20 R. F. Tran s. (Range 5). .. 32-2176
21 Condenser (5 mm!. mica). .. . 30-1077
22 Condenser (40 mm!. mica) ......... . . 30-1076
23 Compen.. tor (R. F. Range I & 2 R. F.). 31-6093
24 Compensator (R. F. Range 3, 4, 5) . 31-6113
25 Resistor (51,000 ½watt) .... 33-351339
26 Condenser (.05 ml. tubular ) . 30-4519
27 Tuning Condenser . ..... . .. 31-1892
28 Resistor (20 ohms, ½ watt) . 33-020339
29 Resiswr (20 ohms, ½ watt) .. . 33--020339
30 Resistor (700 ohms, ½ watt) ... 33-170339
31 Condenser (250 mm!. mica) .. 30-1032
32 Conden,er (250 mm!. mira)... . 30-1032
33 Reaistor (99,000 ohms, ½ watt ) ...... 33-399339
34 Resistor (99,000 ohms, ½ watt) .... .. 33-399339
35 Condenser (,02 ml. tubular) . 30-4481
38 Resistor (8,000 ohm,,, ½ watt ). 33-280339
37 Resistor (20,000, ½ watt) . 33-320339
38 Osc.TraM . (Range I) . 32-2191
39 Osc. Tra09 . (Range 2) 32-2194
40 Osc. Trans . (Range 3) . 32--2197
41 Osc. Trans. (Range 4) 32-2198
42 Osc.Traos. (Range 5)... . .. .. .. .. 32-2199
43 Compensator (Range 1t\ 2 Osc.) ...... 31-6124
44 Compensator(Range3 ,4&5 0sc .)... 31-6117
45 Condenser (250 mm!. mica).. . . . . . . . . 30-1032
48 Condenaer (600 mmf. mica) ... . ...... 30-1049
48XConden,e r (600 mmf . mica) .. . .. . .. . 30-1049
47 Condenaer (.01 mf. tubular) ......... 30-4169
48 Condenser (25 mmf. mica) ... . ....... 30-1067
49 Condenser (55 mmf . miea).. . ........ 30-1045
50 Condenser (200 mmf. mica) .. 30-1078
51 Choke (R. F.) ... . . . . . . .. 32--2242
52 Resistor (75,000 ½ watt) . 33-375339
53 Resistor (20,000 ½ watt) , 33-320339
54 Resistor (32,000 ½ watt) . 33-332339
V,,........__""\i V---------""\'\
~ ~--~~
83B@
I@
83AO
0@0
81C 81D
~ ~
81B O 81A
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t
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I F EXPANDER UNIT
FIJ1.7. I.F. Compensators
List
Price
U.20
1.20
1.20
1.20
.20
.20
.40
1.40
.20
.25
.20
.20
.20
.20
1.00
.70
.70
.70
1.20
.20
.20
.40
1.40
.20
.20
3.75
.20
.20
.20
.25
.25
.20
.20
.20
.20
.20
1.00
1.00
.70
.70
.70
1.00
1.20
.25
.25
.25
.20
.20
.20
.25
.30
.20
.20
.20
Schem. Pan
No. Description No.
55 Resistor (10,000 ½ watt) . . . . 33-310339
56 Condenser (.02 ml. tubular) ..... 30-448!
57 Resistor I10ohms wire wound).... 33-1219
58 Resistor (300 ohms, wire wound) . 33-3121
59 Condenser (.05 mf. tubular) . 30-4123
60 Condenser (.05 ml. tubular ) .... 30-4123
61 Resistor (1000ohms, ½ watt )... 33-210339
62 Resistor (1000ohms, ½ watt ) .. 33-210339
63 Resistor (500 ohms, ½ watt ). 33-150339
64 Condenaer (. I ml. Bakelite) . 4989SG
65 Condenser (.01 ml. tubular) .... 30-4514
66 Condenser 1.01ml. tubular) . 30-4499
67 Condenser (110 mmf. mica). . . . .. . 30-1031
68 Condenser (110 mmf., Part of 82) . . . . 30-1031
69 Resistor (51,000 ohms, }', watt, Part
70
71
72
73
74
75
76
n
78
79
80
)81
of 82) . . . . . . . . . . . . . . . 33-351339
Resistor (I meg., ½ watt) .. 33-510339·
Resistor ( 1 meg., ½ watt)... .. 33-510339
Resistor (2000 ohms, ½ watt) .. 33-220339
Resistor (2000 ohm,, ½ watt) . 33-220339
Condenser (.05 mf. tubular) . 30-4444
Condenser (.05 mf. tubu lar ) .... 30-4518
Condenser (.05 mf. tubular ). 30-4444
Resistor (6,000 I watt) .. 33-260439
Resistor (70,000 1 watt) . . . . . 33-370439
Resistor (14,000 wire wound) ... 33-3291
Condenser (Elec. 8- 8- 6 mf.) . . . . .. . . 30-2232
I. F. Expaod er Unit (For 1st and 2nd
I. F. Tran s. See Note) ............. 38-8912
82 I. F. Tran sformer (3rd) . 32--2660
83 Discrimina tor Trao s.... . . . . . . . 32--2661
84 110 mf. Coodeoser fPart of 83) 30-1031
85 Condenser (.004mf.) . _. . . . . . . . 30-4456
86 Condenser (Part of 82)......... .
87 Resistor (160,000 ohm, ½ watt) . 33-416339
88 Resistor (2 meg., ½ watt) . . 33-520339
89 Resistor (2 meg., ½ watt) . 33-520339
90 Resistor (I meg., ½ watt) .. .. 33-510339
91 Resistor (I meg., ½ watt) ..... 33-510339
92 Conden ser (110 mmf. mica) .. 30-1031
93 Condenser (110 mmf. mica) ... . . 30-1031
94 Resistor (490,000 ohms, ½ wat t) ..... 33-449339
95 Resistor (490,000 ohms, ½ watt ) .... . 33-449339
96 Condenser (.1-.1-.7 mf.) . 30-4466
97 A.F.C. Shorting Switch. 42-1216
98 Flood Lights . .. . . .. . . . . . . .. .. .. .. . 34-2064
99 A.F.C. Shortiog Switch (Part of Mech.
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
Tuner) . . ....... . . . . . . . . . . . .. . . . . . 45-2330
Condenser (.01 mf. tubula r). 30-4169
Volume Cootrol. ................. . .. 33-5158
Audio Shorting Switch (Part of Mech.
Tuner-See par ts (6) aod (16) Bulletin
273)......... ....... ... .. . .
Resistor (70,000 ohms, ½ watt) ...... 33-370339
Resistor (2 meg., ½watt)... . 33-520339
Condenser (.008 mf. tubular) . 30-4112
Condenser (.008 mf. tubular) .... . . 30-4112
Resistor (490,000 ohms, ½ watt ) . . . 33-449339
Resistor (32,000 ohms, ½ watt) . . 33-332339
Condenser (.004 mf. tubular) . 30-4456
Condeoser (.01 mf. tubular) . . .. . . 30-4455
Resistor (51,000 ohms, ½ watt) . . 33-351339
Resistor (99,000 ½ watt) . . 33-399339
Potentiomet er. .. . . . . . . . . . . . . . . . . 33-5235
Resistor (330,000 ohms, ½ watt) . . 33-433339
Condenser (.02 mf. tubular) . 30-4481
Resistor (I meg., ½ watt) . 33-510339
loput Trans ........... ..... 32-7865
Condense r (.05 mf. t.ubular) . . 30-4518
Condenser (.05 ml. tubular) . 30-4518
Resistor (99,000 ½ watt) .. , . 33-399339
Resistor (10,000 ½ watt) .. 33-310339
Resistor (10,000 ½ watt) . 33-310339
Resistor (99,000 ½w at t) .... 33-399339
Coodeoser (.02 mf. tubular) . . 30-448,1
Coodeoser (.02 mf. tubular) . 30-4189
Output Trans ... 32--7751
Cone and Voice Coil Assembly .... 36-3647
Resistor (490,000 ½ watt) .. . . .... . 33 449339
Resistor (51,000 ½ watt). . .. 33 351339
Resistor (25,000 ½ watt) . . .. 33 325339
Condenser (.1- .1 mf. Bakelit e) . . 4899DG
Field Coil Assembly. . . . . . . . . . . .. 36-3788
R"8istor (20 ohms, ½ watt) . .. . . 33-020339
Resistor (3,000 ohms, ½ watt). .. 33-230339
Resistor (2,000 ohms, ½ watt) . 33-220339
Choke (85 ohm) ..... .... .. ....... .. 32-7056
Resistor (4,000 - 1,000 ohms, wire
wouod) . . 33-3289
Choke (400 ohm) . . . . . . . . 32-7722
Condenser (X ml. tubular) .... . . 30-4465
Condenser Elec. (8-10 mf.) . .. 30-2201
Elec. Cond. (8 mf.) .. 30-2026
Elec. Cond. (8 mf.). .. . . . . . . . . . . . . . . . 30-2026
Power Tran sformer (115 V., 50 t-0 60
cycle) ... .... .. . ............. . .... 32-7699
Power Tran sformer (115 V., 25 to 40
cycle) ............. . ....... . . . . .. . 32-7700
Power Transformer (115/ 220 V., 50 to
___ 60_c~ycle) ........ . . ... .. 32-7701
List
Price
S0.20
.20
.20
25
.20
.20
.20
.20
.20
.35
.20
.20
.20
.20
.20
.20
.20
.20
.20
.20
.20
.20
.20
.40
2.50
10.00
.20
.20
.20
.20
.20
.20
.20
.20
.20
.20
.20
1.40
.75
.09
J.20
.20
1.00
.20
.20
.20
.20
.20
.20
.25
.20
.20
.20
.20
.20
.20
.20
.20
.20
.20
.20
.20
.20
.35
2.00
2.50
.20
.20
.20
.40
15.00
.20
.20
.20
2.20
.50
1.20
.25
1.75
1.05
1.05
7.50
'Th ese Automati c Tuning Mechanism Part• differ from those
shown in Service Bulletin 273.
)1st I. F. Traosformer Section ..... . ....... 32--2727
2nd I. F. Traosformer Section ..... . . . . . . . 32-2728
tPilot and Floodlight Socket Aseembly, 3
Sockets. Used on later type receivers . . ... .. 38-8487
Prices Subject to Change without Notice
Schem. Part
No. Ll1t
Price
No.
144
145
148
147
148
149
Power and Tone Switch .. .. ........ 42--1196
Condenser (.015- .015 Bakelite) ... 3793DG
Raoge Switch (Doc.) . . . 42-1217
Range Switch (R. F.). 42-1255
Range Switch (Ant..). 42-1211
r:~s~i~'Ci.;;5~:_......_........ :t~m
Automatic Tuning Mech. Complete .. 31-2063
Bezel Assembly (Cabinet) ..... . . . . . . 38-8833
Bezel Gasket ..... .... . . . .".. . . . . .. . . 27-8828
Brace (Dial Mechanism) ...... . . 28-4119
tCab le and Plug (Floodlights) . . 41-3253
Cable (Power) ..... . . . . . . . . . . L-2183
Cab le and Plug (Speaker) . . . . . . 41-3338
Clamp (R. F . Unit Rear Mtg .) ...... . 28-3900
Clamp Locking Plate (R. F. unit) . 28-3982
Clamp(!. F. Cord) 28-4147
Cord (I. F. Expander Drive) .. . . . . . . 27-8411
Coupliog (Raoge Switch and Mask) .. . 38-8693
CoN!i:!n\;.::;'i og ~ondenser and ~ial 31-1961
'Cover (Handle of Automatic Mech.) . 28-5092
'Di al. . . . . . .. .. . . . . 27-5340
'Dial Screen Holder .......... .. ..... 31-2053
'Es cut~heoo ASS<:IDbly(Statio n Tab s) .. 45-2472
tFloodlight Socket Aasembly, 4 Sockets . 38-8210
Knob (Range Switch) . . . . . . . . . . . . . . . 27-4326
Knob (Tuoing) . 27-4330
Koob (Vernier) .... ..... . .. .. ..... .. 27-4331
Koob (Bass, Volume, Expander Mag-
netic) ......... . . . . . . . . . . . . . . . . . 27-4332
Mask Guide (Tuning Mechan ism) . 28-4118
tP ilot Lamp Socket Assembly ...... ... 38-8051
Shalt aod Index Plate (Range Switch) . 42--1208
Shaft (!. F. Expaoder) ... 28-6496
Shaft (Volume Control) . 38-8061
Shield (Tube, Square).. 28-2726
Shield (Round 6NTG).. 8005
Shield 3rd (I. F.) .. ....... 38-1962
Shield (I. F. Expander). 38-9025
Shield Base (Square) . . . . . . . . 28-2725
Shield Base (Round 6N7G) . 8004
Speaker (W4) ... .. .. . 36-1284
Socket (7 prong, Power tubes) ... 27-6057
Socket (7 prong) . .... . . . . . . . . . . 27-6087
Socket (6 proog). .. . . . . . . . . . . . . 27-6086
Socket (Power Transformer) . . 27-6052
Terminal Pan el (Ant .) . 38-8746
MISCELLANEOUSMOUNTINGPARTS
Bolt (Mtg . Speaker) . . .. . .. . ..... ... . W-862
Bushing (Mtg . R. F. Unit) .. .... . . ... 28-2257
Clip (Volume Shaft Front Section) .. . . 28-4394
Cover (Back of Cabinet). . . . .. . . . . . . . 27-8866
Felt (Mtg. Speaker) .. . .... . . .. . . ... . 27-8498
Rubber Grommet (Mtg . R. F. Unit) .. 27-4317
Rubber Bushing (Mtg. Chassis) ... .. .. 27-4202
Rubber Bushing (Mtg . Chassis) . . . . ... 27-4360
Rubber Cushion (Mtg . Chasis) ....... 3558
Pin (I. F. Shaft) . ..... ...... .... ... . 3014
Screw (Mtg . R . F. Unit RearSection) . . W-729
Screw (I. F. Cord Clamp) . ... .. .. . ... W-1324
Screws (Back Cover, Cabinet) ..... . . . W-1803
SnapF astener(Ra ngeSwitchCoupling) . 28-4279
Spacer (Mtg . R. F. Unit) ... .. . ...... 27-7807
Spring (Retaining I. F . Shaft Front
$0.75
.40
2.00
1.60
1.60
1.25
.08
.05
.25
.40
.03
.01
.01
.04
.80
.10
.10
.10
.10
.25
.50
.30
.12
.10
.10
.20
.03
.11
.11
.11
.11
.01
.01
.15
.04
.08
Section) .. . . . . . . . . . . . . . . . . . . . . . . . . 28-8610
Spring Clip (I. F . Shaft, Rear Section) . 28-4117 per C .40
Washer-Flat-(!. F. Shaft) .. ..... .. . W-174
Washer (Mtg . R. F. Unit ) .... .. . ..... 28-3927 .01
Washer-Spnng-(Mtg. I. F. Shaft) . 28-4186 per C .75
Fig. 8. R.F. Compensator Underside of Chassi s
philcoradio.com

Page S PHILCO Service Bulletin No. 286
Alignment of Compensators
EQUIPMENT REQUIRED : (I) Signal Generator, having a fundamental
frequency range cov ering the tuning and intermedi ate frequencies of th e receiv er.
Philco Model 077 Slj!nal Generator which has a fundamental frequency range
from 115 to 36000 K. C. is the correct instrument for this purpose; (2) Output
Meter, Philco Model 026 Circuit Tester incorporates a sensitive output meter
and is recommended; (3) Philco Fibre Handle Screw Driver, Part No. 27-7059
and Fibre Wrench, Pa rt No. 3164. ·
OUTPUT METER : The 026 Output Meter isconnected to the plate and cathode
terminals of one of the 6L6G tubes. Adjust the meter to use the (0-30) volt scale
and advance the att enuat ot contr ol of th e generat or until a readab le indicati on
is noted o n the out put mettt a ft er signa l is appli ed to stag e bei ng adju sted.
DIAL CALIBRATION: In order to adjust the compensators of this receiver
correctly th e dial mu st be aligned to tr ac k prop erly with th e tunin g conden ser.
To do this proceed as follows:
l. Loosen the set screws o n the shaft coupling of the tuning conden ser. Then
turn the tuning condense r until th e plates are in th e maximum capacity posi tion.
Now turn the dial until th e glowing beam indic ator is on th e Index Line at th e
low frequen cy end of the broadcast ba nd . See Fig. 0. With dia l and tuning co n-
denser in thi s positi on tight en set screws.
2. Turn the tuni ng condenser con tr ol until th e indicato r is on th e 520 K.C .
mark. See Fig. 6.
3. \Vith the dia l in thi s position, loose n t.he shaft coupling set screws. Then
turn th e dial until the indi cato r is again on th e Index Line . Tighten th e set
screws in thi s positi on.
NOTE: Becareful when turning the dial that the position of the tuning condenser
is not disturbed.
INTERMEDIATE FREQUENCY
CIRCUIT
1. View ing eac h instrum ent from the front ,
set the rece iver a nd Sign al Ge nerator co ntrols
as follow s :
a. Selectivity-fidelit y co_nt rol /clo ckwi se)
b. Volume Control at maximum (clockwis e)
c. M ag netic Tuning switc h (off)
d. Bass Comp ensat iorf switc h first position
from "off ''
e. Range Swit ch position one (broad cast)
f. Rece iver dia l 580 K. C.
g. Signa l Gen erator indicator set at 4i0 520 KC.
K. C. and the "Attenuator " control for max- MARK
imum output. GLOWING BEAM
2.·Connect th e Sign al Ge nerator output INDICATOR
cab le through a .1 mfd. co nd ense r to th e grid
of the seco nd 6K7G I. F. t uh e. Th en adjust Fig. 6. DialCalibration
the I. F. compensators as follow s:
a. Clo se compensator (82B) by turnin g to the extr eme clock-
wise position, then pad compensator (82A) for max imum output. Now
readju st wmpensa tor (828 ) for max imum output.
b. Connect th e Signal Ge nerato r output lea d through th e .1 mfd .
cond enser to th e grid of th e 6L7 G tube, and adjust the following com-
pensators for maximum output: (81D), (81C), (81A), (818 ).
c. Rep ad (82A)-Se e Note A. Check for two equa l peaks. Fid el-
ity control in expa nded position (counter-clockwise ).
RADIO FREQUENCY CIRCUIT
I. Set the controls as given under " Intermediate Frequency Circuit" (a-b-c-d )
and set the Range Switch, Signal Generator and Receiver 'Dials as given under
the adjustments of each timing range in the followingprocedure.
Connect the Signal Generator output cable to the "Red" and "Blk" terminals
on the aerial panel (rear of chassis). The ground connectionof the cable should be
connected to the "Blk" terminal.
2. Set th e controls and adj ust the compensators for maximum output as follows:
Tuning Ranges 530 to 1600 K. C.
Range Signal Generator
Switch and Receiver Dial
Position 1 1500 K. C.
Position 1 580 K. C.
Position 1 1500 K. C.
Position 1 1400 K . C.
Tuning Range 4.7 to 7.4 M. C.
Range Signal Generator
Switch and Receiver Dial
Com pensa tors
in Order
(43), (8), (23)
(43A)Roll Tuning Condenser.
See Note B
(43)
(8), (23)
Compensators
in Order
Position 3 7.0 M. C. (44)
Position 3 5.0 M. C. (44A)
Position 3 7.0 M. C. (44), (9), (24)
Position 3 5.0 M. C. (44A), (9A), (24A)
Position 3 7.0 M. C. (44), (9), (24)
Tuning Range 7.35 to 11.6 M. C.
Range Signal Generator
Switch and Receiver Dial
Position 4 11.0 M. C.
Positi on 4 7.5 M. C.
Position 4 11.0 M. C.
Position 4
Position 4 7.5 M. C.
11.0 M. C.
(44B )
(44C)
Compensators
in Order
(44B), (9B), (248 ) Roll Tun-
ing Condenser. See Note B
(44C), (9C), (24C)
(44B), (9B), (24B) Roll Tun-
ing Condenser. See Note B
Tuning Range 1.58 to 4.75 M. C.
Range Signal Generator
Switch and Receiver Dial
Position 2 4.5 M. C.
Position 2 1.7 M. C.
Position 2 4.5 M. C.
Tuning Range 11.5 to 18.2 M. C.
Range Signal Generator
Switch and Receiver Dial
Position 5 18.0 M. C.
Position 5 12.0 M. C.
Position 5 18.0 M . C.
Position 5
Position 5
12.0 M. C.
18.0 M. C.
Compensators
in Order
(43B), (8A), (23A)
(43C)
(43B), (8A), (23A)
(44D)
(44E)
Compensators
in Order
(44D), (9D), (24D) Roll Tun-
ing Condenser. See Note B
and C. Check image at
17.060 M. C.
(44E), (9E), (24E) Roll Tun-
ing Condenser. See Note 8
(44D), (9D), (24D), Roll Tun-
ing Condenser . See Note 8
and C. Check image at 17.060
M.C.
NOTE "A" ·- Slow ly :-::hift signa l generator indi ca tor betwE>en 460 a nd 4RO K. C.
.-\s the in<lic;1.tor is turn ed, tw o pe.aks will be noted on the Output Me ter; one about
465 K. C. and the other about 475 K . C. Thesepeaks shouldgivethe samedeflection
or rearling on th e out put met er. If the pea ks a re unequal Comp ensator (82A) mu st
be slightly readjusted to the right or left (not more than Ysof a turn ) until the peaks
are equalized. Thi s ad ju stment is used to r.ompens ate for slight differences between
peaks. If th e compen sa tor mu st he turn ed more th a n ½ of a turn in eithe r direc tion
to equalize the peaks, all padders should be carefully readjusted as given under
·· 1nt ermerliate Frequ ency Ci rcuit" adju stm ent nrocedure. Each time th e co mpe n-
sator is set in another positi on, rotate th e signal genera tor thr ough th e 460 or 4R0
K. C. range an d not e th e readin g of ea ch pea k.
NOTE "B"- When adjusting the low frequency compensator of Range One
(Broadcast) or the a nt enna anrl R. F. compensators of th€' high frequ ency tun ing
ran ges ; th e receiver Tuning Co ndenser mu st be ad ju sted (ro llerl) as follows : Fir st
tun e th e co mpens ator for maximum out put, then vary the tu ning condense r of the
rece iver for maximum output abo ut th e frequ ency dial mark. Now turn the com-
pensa tor sligh tly to th e right or left am t var y th e receiver t uning condenser for
maximum out put. If the ont readin g increase~. turn the compensa tor in the same
direct ion a trifle more, and again vary th e tuning conde nser for maximum output.
If the output decr easeg, set th e compensator in th e opposit e di rection . This pr o-
cedure of first sett ing the compensa tor and then varying the tuning condenser is
continued until th ere is no furth er gain in output read ing.
NOTE "C"-T o accu rat ely ad just the high frequency osci llator comp ensato r
to the fundamental in stead of th e image signal, turn the oscillator compe nsator
to the maximum capacity po sition (clockwise) . Fr om this positi on slowly turn the
compensat or counter-cl oc kw ise until a seco nd m aximum peak is ob tained on th e
output meter. Adju st the comp ensator for maximum outp ut using this seco nd peak.
The first pea k fr om maxi mum capacity pos ition of the comp ensator is the im age
signal and mu st not be used in ad justin g th e compensator.
If the above procedure 'is correctly performed, the image signal will be found
(much weaker) by turning the receiver dial 940 K. C. below the frequency being
used on any high fre quenc y rang e.
MAGNETIC TUNING CIRCUIT ADJUSTMENT
a. Set the Ma gneti c Tuning switc h in th e '\ mt " posit ion (count er-
cloc kwi se).
b. Volume co nt ro l maximum (ext rem e clockwise ).
c. Turn Treble-Selectivit y co ntrol to the expanded positio n
(extrem e clockw ise).
d. Now, adju st the "Att enu ato r" control of th e signal generator
for a wea k signal , and turn the indi ca tor to 1000 K. C. Th en adjust
the receiver dial for maximum output at this frequency .
NOTE: The rece iver dial MUST be tun ed very ac curat ely to the
1000 K . C. signal in orde r to make the following adjustment s
cor rect ly .
e. After ad ju st ing th e receiver dial, turn the Magneti c Tunin g
switch "on ."
f. Now, turn co mpensator (83B) sligh tly to th e right or left (about
¼ turn) and proceed with adj ustmen t "g."
g. Adjust compensator (83A) primary of the discr imin ato r trans-
former for minimum output; then readjust compe nsator (83B)
seco nd ary of dis criminator tran sfor mer for maximum output.
The above adjustments are nowchecked for accuracy as follows:
Frequency Test:
With th e 1000 K. C. signal tun ed for maximum output turn the Ma gnetic Tuning
control bac k and forth ; that is, from th e "ou t " t o " in " posit ion. Th e rea ding of t he
output meter shou ld no t change in either position. If th e output meter read ing
changes, th e above m ag neti c tunin g circuit ad ju st ment s shou ld be repea ted.
Sensitivity Test:
1. To check th e ma gneti c tuning circuit for sensi tivit y,-turn the mag netic tunin g
switch to the "off" position, and tune in the 1000 K. C. signal. Then adjust the
"a tt enuat or" contr ol of the signa l generator for a good audible signa l. Approxi-
mately 20 volts on the output meter.
2. Now detune the signal (first above and then below the 1500 K. C. mark) to a
poi nt at whi ch th e signa l is weak ly hea rd . At each point turn the mag neti c tun ing
contr ol "o n." When the contr ol is turned on th e signal should return to norm al
output str ength. If the ma &,netic tuning circu it does not pull the signa l into reso-
nance, the primary compensator (83A ) should be carefully readjusted.
June, 1937
PHILCO RADIO AND TELEVISION CORPORATION
Parts and Service Division -Philadelphia, Pa. Printed in U. S.A.
philcoradio.com