Philco 38-14 Reference manual

• • • • • 'irlorM 38-11/.,CJJdeA.121& 12ft.
SERVICEBULLETINNo. 288 lo, members ol
RADIO MANUFACTURERS SERVICE
Electrical Specifications
TYPE OF CIRCUIT: A. C. or D . C. ope rated superheterodyne with automatic
volume control . pentode audio output, and covers the standard broadcast,
municip .al and state police frequencies, first class amateur (night ) and man y
night foreign and American short-wave stations.
Code I21 & 124 chasses of this Model are identical with the exception of
electrolytic condensers, speaker and cabinets. These differences are listed on
the part list.
POWER SUPPLY : Volta~e Power Consumption
115 55 watts
INTERMEDIATE FREQUENCY: 470 K. C.
R. F. TUNING RANGES : 540 to 1720 K. C.
2.3 to 7.4 M . C.
AUDIO OUTPUT: I watt
PHILCO TUBES USED: Five: one 6A7, Det. osc.; one 78, I. F.; one 75, 2nd Del.,
Isl Audio; one 43, Output, and one 25Z5 Rectifier .
TUNING MECHANISM: 12 to I Rati o•using Pulle y and Cord.
CABINET: Type "T," Code 121
Type "CS, " Code 124
Alignment of Compensators
EQUIPMENT REQUIRED: (1) Signal Generator, using a fundamental
frequency range covering the tuning and intermediate frequencies of the receiver .
Philco Mode: 077 Signal Generator which has a fundamental frequency range lrom
I IS to 36,000 K. C. is the correct instrument for this purp0se; (2) Output meter,
Phiko Model 026 circuit tester incorporates a sensitive outp ut meter and is recom-
mended; (3) Philco Fibre Handle Screw Driver , Part No. 27-7059 and Fibre Wrench,
Part No. 3164 .
OUTPUT METER: The 026 Output Meter is connected to the plate and
cathode terminals of the 43 tube . Adjust the meter to use the (0-30) volt sca le and
advance the atte nu ator contr ol of the generator until a readable indication is noted
on th e output meter after signal is applied.
DIAL CALIBRATION: In order to adjust the receiver correctly the dial
must be aligned to track properly with the tuning condenser. To adjust the dial,
proceed as follows:
I. Turn the tuning condenser to maximum capacity position (plates fully
meshed).
2. Holding th e tuning conde nser in this position, turn the pointer until it is
pa ralle l with the index lines (see Fig. 3). Thi s is the correct position of p0inter at
maximum capacity of tuning condenser .
INTERMEDIATE FREQUENCY CIRCUIT
When adjustin& the following compensators, a Philco Set Transformer Part
No. 32-2763 must be connected in the signa l generator output circuit as follows:
Insert the signa l generat or output lead into the " Med" jack and the ground
lead into the " Gnd" jack of the signal generator.
0
0D
□
Fig . l. Locations of Compensators-Top of Chassis
A PHILCO Service Pion
~v VOLTAGES MEASURED FROM SOCKET
CONTACTS TO MINUS ·s·.
~SV. 2ND .DET
A VC I.F. DET-OSC .
. OUTPUT-43 1STAUDIO 78 6A7
~~1ope~j.f,~Ritv:~
2
_
5
l~5~Vi:.~1 ~H~ ssv]~fr~
ij
o 017 Hijo@ bKH~ o 0D2 Hij OS-,& ~ @ ~
OK OP ~OK J ~OK J 108V~
H @ H @ l:!.._..)"'@ l:!.._..)"' . ~~
-25V. -25V. -£,.'3V. -£>.3V. 6.'3V.
Fig . 1. Socket Volta~e-Underslde of Cha,;;;l11View
The voltages indicated by arrows were measured with a Philco 026 Circuit
Teater, which contains a sensitive voltmeter. Volume Control at minimum-
Tuning Condenser set for no signal-line voltage 115 A. C.
Connect the other end of the output lead to terminal No . I on the Set Trans-
former and the cable ground to Terminal No. 2. No . 3 and 4 terminals of Set
Transformer are then connected to the chassis and 6A7 grid respectiv ely of th e
receiver with short pieces of wire . Insert a 0.1 mfd . in series with the No . 4 lead
which connects to the grid .
SET POINTER PARALLEL WITH INDEX LINES
Fig. 3. Dial Pointer Calibration
Set the signal generator and receiver controls and adjust the I. F . compen-
sators as follows:
1. Set Signal Generator at 470 K. C. Turn "Multiplier" Control to 1000
and the "Atte nuat or" for maximum output.
2. Turn the receiver dial to 580 K. C.
3. Range Switch Broadcast p0sition.
4. Receiver volume control maximum.
5. Adjust compensators, (17A), (14B), (14A), for maximum output. If the
output meter goes off scale when adjusting the compensators, ret ard the signa l
generator attenuator .
RADIO FREQUENCY CIRCUIT
Tuning Range: 2.3 to 7.4 M. C.
1. Remove terminal No. 4 lead of set transformer, from the 6A7 grid and
connect to the aerial wire of the receiver through a 400 ohm resistor . Remove the
.I mfd. condenser when using the 400 ohm resistor.
2. Set the controls and adjust the R . F . compensator's as follows:
Range Volume Si~nal Generator
Switch Control and Receiver Dial R . F. Compensators
Shortwave Max. 6 M . C. (4B)
Tuning Range: 530 to 1720 K. C.
1. Remove the 400 ohm resistor from the No. 4 lead and replace with a 100
mmfd. condenser and reconnect to the aerial wire .
Set the controls and ad just the R. F . compensators as follows:
Range Volume Si~nal Generator R. F. Compensators
Switch Control and Receiver Dial In Order
Broadcast Max. 1550 K . C. (12A), (4A)
Max. 580 K. C. (12) Roll Tuning
Condenser
Max. 1550 K. C. (12A) , (4A)
Copyright 1937 Philco Radio & Television Corp0ration
philcoradio.com

Page2
Replacement Parts
Sch... .
No. o-iptlon
1 Cond. (t\ibular.001 mf.)..... . ... . . . . . .. ... .
2 Ant. Trans. (Range 2).... .....•. ...... . • ... ..
3 Ant. Trans . (Range 1).. . .. .
4 Tuning Cond. Amembly.
5 Cond. (tubular .15mf.)
8 Cond. (tubular .05 mf.).
7 R,sistor (120,000ohm ½ watt) . . .... ... . ... .
8 Cond. (mica 250mmf.).. ....... .
9 Cond. (tubular .05mf.) ... ... . .
10 Resistor (5000 ohm½ watt ).
11 Osc.Trans .. ......... ....... .
12 Compensator .. .
13 Cond. (mica 1650mmf.) ... . .
14 I. F. Trans. (1st).
15 Resietor (25,000 ohm ½ watt)
18 Ret<istor(2 meg. ½ watt) ..
17 I. F. Trans . (2nd).
18 RMistor (51,000 ohm ½watt) .
19 Cond. (tubular .01 mf.).
20 Volume Control .. ..
21 R,sistor (4.0 meg. ½ watt) .
23 RMistor 020,000 ohm ½ watt)
24 Re6ietor (490,000ohm ½ watt) .
25 Cond. (tubular .02 mf.)
28 Output Trans. (B 0-2).
Output Trans. (S-18).
27 Cone and Voice Coil Aesembly (S-18)...
Cone and Voice Coil Assembly (B-0-2)
28 Electrolytic Cond. (20 mf. Code 121).
Electrolytic Cond. (Code 124)..
29 Resistor (27 ohm ½ watt) .
30 Cond. (tubular) .05mf.....
31 Resistor (300 ohm, 2 watt) .
Part
No. Lilt Price
$0.20
.25
.20
.20
.25
.20
.20
.35
2.20
.20
.20
1.50
.20
.20
.20
.20
.20
.20
1.10
.95
.20
.20
PHILCO Service Balletin
:1
©ANT .RANGE: 'Z
' 24S,6,3
A3
11...®
51-
•-zO'!!.
1 TRANSrORMERS SHOWN
WITH INDEX SLOT IN rRONT .
6}
DIRECTION or ROTATION
rROM REAR or SWITCH .
A~A4:S 6
A2 7
A1 0 38
0 -
SWITCH SHOWN f"ROM RE:AR Of' CHA:-
·SSIS,(80TTO~ v,cw). SHOWN IN
POSITION No .I (BRC?A_D_C_A_St~J__ _
RECTIFIER
2525
'@
<
..,
"'
i
:::
_./ /
2No.DET ·AV .C.
1ST.AUDIO
75
~
.o,.,.t.
@'
~-~
~~'
/ -05....f.
21A
(
?
I.F'.=470 K.C.
32 Electrolytic Cond. (16 mf. Code 121)
Electrolytic Cond. (Code 124)..
3«H453
32-2720
32-2718
31-2094
3«Hl91
3«H519
33-412399
30-1032
3«H444
33-250339
32-2719
31-6209
5877
32-2672
33-325339
33-520339
32-2674
33-351339
30-4479
33-5236
33-540339
33412339
33449339
30-4215
32- 7874
32-7395
36-3014
36-3981
30-2245
30-2275
33--027339
304444
33-1258
30-2246
30-2277 .90 FIii,. 4. Schematic Dla1tram, Model 38-14, Code 121
33 Choke...... .
34 Field Coil and Pot . All8elllbly(S-18). 32- 7868
36-398.'\
•Field Coil and Pot. A86elllbly(B 0-2) .. (See Speaker Note below).
35 Condenser (tubular .01 mf.) ... . . . 30-4169 .20
38 Filament Reeistor (133 ohm- 15 ohm)
37 Pilot Lamp ........ .
38 Range Switch.. .. .. .... . ..
Cahle Speaker (Code 124).. .
Cable (Power) ....
Clip, Small (Mtg . R. F. Coil).. ... •• .
Clip, Large (Mtg . R. F. Coil) ... .. .. .•
Dial AM'y. ........... .. .. ...... ... .
Dial•Pointer . . ... .. .. . . •. . . . . . .. • ....
Dial Drive Cord ..
Dial Drive Shaft
Insulator Washer ( Electrolytic) ____..
Insulator Wuher (Electrolytic ) •...
Insulator Cover I.ls (Elec . Cond.31.)
Insulator Cover
11~ (Elec. Cond. 32)
33-3322
34-2068
42- 1366
L-2984
L-2778
28-5002
28-5003
31- 2098
28-5201
31- 2096
38-9001
27-8882
27-8883
27-8800
27-8905
.65
.12
.70
.40
.02
.03
.20
.10
Schem.
No. Deacrlptlon
KnobAsay
Mtg. Rubber Dial
Mtg. Rubber (Tuning Condenser) .
Pilot Lamp Ass'y.
Pilot Lamp ..
Pully (Tuning Conden.ser).. . .. .. •. . •..
Speaker (B 0-2, Code 121).
Speaker (S-18, Code 124)
Put
No.
27--4604
27--4150
27--4596
38-9127
34-2068
.. 31-1283
36-1367
Socket (
6 prong) . . . . . . . . . . . . . . . . . . . . . . . .• . . . . 27- 6036
Socket (7 prong) . 27-6037
Washer "C" (Tuning Shaft) .. . . 28-3904
Bezel and Glass (Code 121). . . . . . •. .. . . .. . . . . 40-6158
Bezel and Glal!S(Code 124) ..... 40-6264
Bezel Clamp . 28-5153
List
Price
$0.01
.12
.30
.It
.It
.01
.02
•Entir e Speaker must be replaced when field coil isopen or damaged.
PHILCO RADIO AND TELEVISION CORPORATION
July, 1937 Parts and Service Division Philadelphia, Pa. Printed in u.s.A.
@@
oo
0(o
0 0 0
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FIii,. 5. Part locations, Underside of Chasals
No. 288
philcoradio.com