Philco 39-55 User manual

• • • • • • • 'fflDdRJL 39-55,39-116
SERVICEBULLETINNo. 310 for membersof
RADIO MANUFACTURERS SERVICE
A l'HILCO Service l'lan
SPECIFICATIONS
Model 39-55
TYPE CIRCUIT: Philco Model 39-55, code 121, is an 11-tube
receiver employing a superheterodyne circuit for reception of
standard broadcast stations with Philco Mystery Control for
Electric Automatic Tuning of eight (8) stations. The Philco
Mystery Control also controls Volume and turns off set with-
out any connections between receiver and Control Unit. In
addition, other, features of design are-Automatic Volume
Control; Continuously Variable Tone Control; Bass Com-
pensations ; Degenerated Push-pull Pentode Audio· Output
Circuit, and Compensators selected for minimum drift.
POWER SUPPLY: 115 volts, 50 to 60 cycles, A.C.
POWER CONSUMPTION: 180 watt.
TUNING RANGES: 540 to 1720 K.C.
I.F. FREQUENCY: 470 K.C.
PHILCO TUBES USED: Receiver--6J8G, First Detector Oscil-
lator; 78, I.F. Amplifier; 6Q7G, Second Detector, A.V.C. and
first Audio; two (2) 42 Audio Output, and one 80 Rectifier.
Mystery Tuning Control Amplifier-78, First Control
Amplifier; 6J7G, Second Control Amplifier; A.V.C.; 6ZY5G,
A.V.C. and a 2A4G Thyratron Rectifier.
Mystery Control Unit-One type 30.
AUDIO OUTPUT: 10 watts.
CABINET DIMENSIONS: Height Width Depth
Console .. ......... . . .. .... 38¾" 29½" 14¾"
Mystery Control . . . . . . . . . . 5½'' 7¼" 9½"
Note: The Schematic Diagram and Replacc~ent Parts List for Model 39-55
will be found in Bulletin 310 A.
Model 39-116
TYPE CIRCUIT: Philco Model 39-116, code 121, is a 14-tube
receiver employing a superheterodyne circuit with three tuning
ranges for reception of standard and short wave broadcast
stations and Philco Mystery Control for Electric Automatic
Tuning of eight (8) standard broadcast stations. The Philco
Mystery Control also controls the volume and turns the set
"off" without any connections between the receiver and con-
trol unit. In addition, other features of design are-Automatic
Volume Control; Continuously Variable Tone Control; Bass
Compensation Degenerated Push-pull Pentode Audio Output
Circuit , and Compensators selected for minimum drift.
POWER SUPPLY: 115 volts, 50 to 60 cycles, A.C.
POWER CONSUMPTION: 190 watts.
TUNING RANGES: 540 to 1720 K.C.; 1.7 to 5.8 M.C.; 5.8 to
18 M.C.
I.F. FREQUENCY: 470 K.C.
PHILCO TUBES USED: Receiver--6K7G , R.F. Amplifier;
6A8G, First Detector Oscillator ; 78, I.F. Amplifier ; 6Q7G,
Second Detector, A.V.C. and first Audio; 37, Phase Invertor;
two (2) 42, Audio Output, and one 80, Rectifier.
Mystery Control Amplifier-78, First Control Amplifier ;
6J7G, Second Control Amplifier; 6J5G, A.V.C.; 6ZY5G, and
a 2A4G, Thyratron Rectifier.
Mystery Control Unit-One type 30.
AUDIO OUTPUT: 10 watts.
AERIAL AND GROUND: To obtain maximum performance
from this receiver, the Philco Safety Aerial, Part No. 40-6370,
should be used. The antenna circuit of this receiver is especially
designed for use with this aerial. When installing the aerial,
care should be taken to keep the aerial lead-in wire away
from the horizontal inductor coil located in the bottom of
the cabinet.
Do not coil up any excess lead-in and drop it in the back
of the cabinet. Run the aerial lead-in directly to the "Ant"
terminal post on the back of the receiver. A good ground con-
nection should be connected to the terminal post marked
"Gnd." When this is done, the link connecting to the "Gnd"
terminal should be disconnected and swung around so that it
does not touch the "Gnd" post. If, however, no ground is used
this link should be connected to the "Gnd" terminal.
CABINET DIMENSIONS: Height
Console .......... . ...... . . 36¾"
Mystery Control . . . . . . . . .. 5½"
Width
34¾"
7¼"
Depth
14¾"
9½"
Adjusting Mystery Control for Reception of Stations
The procedure for setting up stations on the Mystery Control
receivers is similar to the procedure followed in setting up P~lco
Electric Automatic Tuning Models. The eight (8) stations, how-
ever, are automatically dialed by the remote control unit instead
of by pushing buttons.
To set up stations on Mystery Tuning, proceed as follows:
1. Select and remove the desired eight (8) station call
letters from the station tab card supplied with the
receiver. Insert the station tabs in the apertures
(windows) of the bezel. The lowest frequency station
is placed in the first window on the left, and the remain-
ing station -tabs in the order of increasing frequency .
2. Connect a Model 077 Signal Generator to the "Ant"
and "Gnd" terminals of the receiver , set the Signal
Generator with modulation "On." Turn the range
selector switch to "Broadcast" and tune in the lowest
frequency station. This should be between 540 -and
1030 K.C. Then adjust the Signal Generator to the
frequency of the station until a beat note is heard.
3. Leaving the Signal Generator connected, turn the
Range Selector Disc of the receiver to "Automatic."
Now, using a padding screw driver, adjust the first
540 to 1030 K.C. oscillator padder (bottom row of
holes) at the rear of the chassis, until the station
identified by the modulated signal of the generator is
tuned in to maximum signal. Next, adjust the first
540 to 1030 K.C. Antenna Padder (top row of holes)
for maximum signal.
4. Turn the Signal Generatoi: off the station frequency
and readjust the "Ant" and "Osc" Padders for maxi-
mum output . This should be done with the volume
control adjusted for low volume. This procedure is
repeated for each of the remaining stations. The next
station, of course, will be the next highest in frequency,
that is within the 540 to 1030 K.C. range of the second
set of padders. The Third Station is adjusted by the
third set of padders under 670 to 1160 K.C. and the
remaining stations in the order of increasing frequency.
5. Now, insert the small call Jetter tab of the first station
in the third aperture of the bezel on the remote Mystery
Control unit. Celluloid tabs are also supplied to be
placed over each call letter . The remaining call letter
tabs are then placed in the order of increasing frequency
around the bezel from right to left (counter clockwise) .
6. Insert the "loud" and "soft" tabs in the first and second
apertures ·o.n the right hand side of the bezel. See
instructions ·supplied with each model for -dialing sta-
tions and controlling volume.
Copyright 1938, Philco Radio & Television Corp.
Phila., Pa.
philcoradio.com

No. 310 PHILCO Service Bulletin Page 2
Replacement Parts Model 39-116
Sclwm.
.!\o. De:-inlp tlon Part No.
I
2
3
4
5
8
7
8
9
10
II
12
13
14
15
16
17
II
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
38
37
38
39
40
41
42
43
44
45
48
47
48
49
50
51
52
53
54
55
58
57
58
ff
ea
81
82
83
14
85
..
87
..
..
70
Anlenn• T... n,rormer (BC! ........ . .. .. . . . 32-30:;6
Antenna Translormer (l'olh-e) . ... .. •... . .. a:t-3U53
Antenna Tran sforme r (S. W.) . .... ..... . .. . 3;l-3055
l'omi;enut or Antenn• Shortwave ..... . ..... 31-6212
~ ~1~ ~~~ Ytrtiise:in\i~½
1
~~itti::::::::::::~g:~~rn39
lle slslor (2.0 meg.-'h wall! . .. . .. . .. . . .. . 33-520339
Tubuhtr Condenser (.1 mfd.) .......• ••. . . . 30-4455
i~;t~:!;~1i~~ff0;~~;t:::::::::::::Uillij
39
H.1''. Tunsrormer (Po lke) ..... . . • ...... . . 32-3054
R.F. Tnn: ;form er (S .W .) ..... .. .. . ........ 32-3046
~llc-11.Con<.lenser (5 mmfd.) .•.••••..• • • •• • .• 30-1097
Com1,en~ator R.F. Shortwne .... . .... . . . ·- . 31- ti:lU
Tubular Condense r (.05 mfu.) ......... ... . 30-4519
Resistor (51,000 ohm-½ wall) ...... . . . .. . 33-3" l339
g::rn:1:r i~~~ ~~~~::~ ~~~fi/e,<,~~~::::::::~t5t~g
Osc-11111.tor Tran sformer (S.\V.) ..... . ..... .. 32-3051
Compensato r Strip (oscillator) . .... . ... .. .. 31-6266
Compen sator Broatlt •as~ Low Frequ enry . . . . . 31-6230
Condenser Sem1-ftxetl (1230 mmM.) . . . ... .. 31-6262
Condenser Semt-ftxed (342:i mmftl . ) ...... . • 31-6263
)fka Condenser (250 mmfd .) . . . .......... . 30-1032
lleslstor (32,000 ohm-½ watt) . ....... . ... 33-332339
Resis tor (10,000 ohm-½ wall) ............ 33-310339
t:::1~;iitxxx~~::;=! ~:m::::::::::::iJ:gm~:
Ele<·trolytlr Conden ser (4 mftl.-250 Y .) .... 30- 2334
l\llca Conden ser (250 mmftl.) . . . . . . . . . . . . . . 30-1031
1st I F .. Tran sformer Assembly ..... . . . . .. , . 32-3089
Tubular Condenser (.01 mfd.) ...... . .. ...
~ 30-4572
Resis tor (1.0 rnea:.-¼: watt) .... .. . . .... .. 33-!i l03 39
Resi stor (330.COOohm-½ watll .... ... .... 33-433339
Resistor (330.000 ohm-½ watt) . .......... 33-433339
?.nd I.F . Trando rmer Assembly ... . . . . .. . .. 32-2645
Min Condense r (110 mmfd.) ... . . . ... . . . 30-10 31
Tubular Condenser (.01 mfd.) ............. 30-4479
Min Condenser (50 mmfd .) ...... . . . ..... . 30-1029
Yolume Contr ol . .. . . ................. . ... . . 33-5300
Resistor (70,000 ohm-•,. waU ) .. ... . . . . . . . a3-3 70339
Tubular Condenser ( 004 mfd.) ..... . .... .. 30-4334
Resisto r (2.0 meg,-½ wall) .. .. .. .. ... . .. 33-52 0339
Tubular Conde nser (.015 mfd .) .. . ..•.. . ... 30-4:i29
Resistor <J.O meg.-1, walt) . . . .. . . .. ... . . 3a.51oa39
Tubular Condenser (.1 mftl .) . . . . .. .. . . .. .• 30-4:i27
Resis tor (99.0 00 ohm-½ wall) . ... . . . • .. .. 33-3!19339
Tubular Conde nser (.01 mid. l ............. 30-41 69
Resistor (490.000 ohm-•,. watt) ........... 33-449339
Resistor (!i.000 ohm-% watt) ... . ... . . .... 33·250339
Resistor (45,000 ohm-½ watt) ... . . . .. .. . . 33-345339
Tubula r Conde nser (.02 mfd .) ........ . .... 30-44 81
Tone Contr ol (3 mer.) .. .. . . .... ... .. .. ... 33-5287
Tubular Conden ser (.01 mfd. ) . .... . ... . ... 30·4572
Tubular Conden ser (.01 mid.) ........... . . 30-4572
Rea18tor ( 51,000 ohm- ½ watt) . . ... .. .. . . 33-351339
Restator (490.000 ohm-½ wall) ... .. .. . ... 33-449339
Resistor (490,000 ohm-½ wall) ... .... .. .. 33-4 49339
Resistor (240.000 ohm-½ watt ) . . . . . .... . . 33-424339
Tubular Condense r (. 1 mfd.) .... . . .. . .• .. . 30-449 9
Tu bular C'ondenaer (.01 mfd.) . ........ . ... 30-4501
Output Tra nsfor-mer ... .. ... . . . ... . . . .. .... 32-7998
Voice Coll & Cone Auembly (Speaker No.
36-1450) . ......... . .... . ....... .... .... 36-4089
Tubular Condense r (.01 mrd.) . . ......... . . 30-4501
Re sisto r (3.000 ohm-½ watt ) . . . .. . . .. , . . . 33- 230339
Resi stor (1.0 mee.-½ watt) . . ... . ... . .... 33-510339
Eleclrolytt c Condenser (25 mld .-300 V. ) . . . 30- 2360
Ele clr olytlc Condense r (18 m!d .-475 V.) .. . 30-2200
S<.·ht>m.
No.
71
72
73
74
75
78
77
78
79
80
81
82
83
14
85
88
87
88
89
89A
89B
89C
89D
89E
89F
896
89H
90
90A
11GB
90C
90D
BOE
90F
906
90H
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
108
107
108
109
110
111
112
113
114
115
Ill
117
Ill
119
120
121
122
123
De s!'rlptlon
Field Coil (Replal'e Speaker No. 36- 1450) . .
Re sistor (Wirewound-Bias) ...... . ..... . . .
Power Transformer (11 5 V.- 50 to 60 <·yt•les).
Power Trans. (115 V.-25 to 4U 1•yt•lell)....
Bypai;s Condenser (.O.:,mfd,) (110 V. ptue) .
Pilot Lamp (Bullseye) . .. . . .. .... .. ... .. . .
Pilot Lamp Heust or (16 ohm) . . ... . , .... . .
PIiot Lamp s (Dial) ........ .. . ... .. . .. . .. .
Filament Trans . (115 V.-50 to 60 cyc les) . .
Filament Tnns. (115 V.-25 to 40 cydes) ..
Motor Trans. (115 V.-50 to 60 ey<:les)... .
Mctor Trans. (115 V.-25 to 40 cyr les) .. .. .
Motor (Volume Control) Assemb ly . . . .... . .
llotary Swlt<·h (Stepper Unit) . . ..•..••. .. •
B.C. Resis tor (10 ohm) Wirewound ... .. ... .
Pilot Lamp Assembly (Statton Indicator) . . .
Switc h (Volume Control-l lotor) .. .. .. ..•. .
Resistor (150 ohm-% watt) . . .. .. ........ .
TubuJar Condenser (.1 mfd .) . .. . . . ...... . .
Tubular Conclenser (.1 mflt .) . ... ., .... . . . .
Electrolytic Condenser (30 nifd .-3 0 V.) .. . .
Push Button Packler Unit .... . ... . . .. . . .. .
CompensatorNo. l ( 540-1030K.C . ) P artof89
Compensator No. 2 ( 540-103 0K .C.) Partof89
Compensator No. 3 ( 670-116 0K. C.) Partol89
CompensatorNo. 4 ( 670-1160K.C .) Partol89
Compensator No. 5 ( 900-1470 K.C.) Part of 89
Compensator No. 6 ( 900-1470 K. C.) Part or 89
CompensatorNo. 7 (1100-1600K.C.) Partol89
Compensator No. 8 (1100-1600 K.C.) Partol 89
ElectrJc Push Button Tr ansform er Assemb ly
Part No.
33-3364
32-8001
~2-8017
30-4576
34-2210
33-016431
34-2004
32-7993
32-80 16
32-799 0
32-8015
35- 1151
42-1468
33, 3363
34-2064
42-1469
33-115339
30-4499
30-4499
30-236 1
31-626 4
(8 Trans .) .. . .... . .............. .. ..... 32-3091
OscUlator Trans . No. 1 ( 540-1030 K .C. ) . ... 32-3042
Oscillator Tran s. No. 2 ( 540-10 30 K.C . ) .... 32-3042
Oscillator Trans . No. 3 ( 670-1160 K.C . ) . . . . 32-3042
Osrtllalor Trans. No. 4 ( 670-IHIO K .C.) .. .. 32-3042
Osctllalor Tran s. No. a ( 900-1470 K.C . ) . . .. 32-3041
Osctllalor Tran s. No. 6 ( 900-1470 K.C.) .... 32-3041
Oscillator Tran s. No. 7 (1100-1600 K.C .) .. .. 32-3041
Osctllator Trans . No. 8 (1100-1600 K. C.) . .. . 32-3041
Silver Mlca Condenser (370 mmfd.) . . .... .. 80-1110
Sliver Mica Condenser (370 mmftl) .. . . . . .. 30-1110
Bakelite Condenser (.05 mfd.) . . . . . . .... .. . 3615-SG
Resist or (150 ohm) .. . .. .. . .. .. .. .. . .. .. .. 33-3362
Electrolytic Condenser (16 mr,1.-200 V.) .. . 30-2356
Cho'<e Coll .. . ... .. .. . .. . . .... . . . .. ... .. . 32-1281
Tubula r Condenser (.05 mfd.) . .. .. ... ..... . .. 30-4123
Tubular Condenser (.05 mid.) . .. .. . . .. . : . .. 30-4113
Tubula r Condenser (.1 mfd.) . . . . . . . . •• . . . . . 30-4499
Tubular Condenser (.5 mfd.) ........ .. . . ... 30-4551
Resistor ( 4.000 ohm--'-½ wait) . .... .. . . . . . 33-240339
Resistor (51.000 ohm-½ watt) . . .. .. ... . .. 33-351339
No. 3 Control Amp_ Transformer .. . . . ...... 32-3088
Tubular Condenser (.02 mfd . ) : ............ 30-4516
Mica Condenser (550 mmfcl.) .. . .. ... . • •. ... 30-1092
Resistor (750,000 ohm-½ wall) ... .. . •... . 33-475339
Resistor (1.0 meg.-1, watt) . ... .. ... , . ... 33-510339
Resis tor (99,000 ohm-½ wall) ... .. . . . . .. 33-399339
Tubular Condenser (.05 mid.) ...... . . ..... 30-023
Resistor (99,000 ohm-½ wall) . . . ... .• . . .. 33-399339
Tubular Condenser (.05 mid.) .... .. . ... .. . 30-4123
Tubular Condenser (.05 mid .) ........ . .... 30-4444
Resistor 0. 5 mer .-½ watt) . . . . . . . . ... .. . 33-515339
Tubular Condenser ( 05 mfd .) . . .. .... .... . 30-4519
No. 2 Control Amp. Tran sformer . . . . . . . . . . . 32-3087
Tubu lar Condenser (.05 mid .) . . . . .. . . . . .. • 30-4444
Renstltvlty Control . . . . .. . .. .. . .. . . .. .. .. . 33-5295
Reslal01' (300 ohm-¼ watt.). . .. .... . .. .... 33-130339
No. 1 Control Amp . Transforme r .. ... . .. , . . 32-3086
Sllrer Mira (200 mmld.) .. . . ... .... . .. . ... 30-1122
Compensator {Se<-ondary lnduetor ) .. . .... . . 31-62fi8
!le<ondary Inductor (Mystery Tunlnc) . .. ... 40-6415
Wave Switch ..... .... ..... ... ........... 42-1451
Mystery Control Unit
Schem .
No.
124
125
128
127
128
129
130
Descrlptlon
l'rima t·Y Induc tor . . .... . ..... . . .• • • .... . .
Stiver )flu Conll. .. .. .. . . . ...... •• . . . .. ..
Air 1-'adder .. . ... . .... . ....•....•• . . . ... .
Tubular Cond. (.05 mt.) ...•.. . .. . .. . . . .. ..
Resistor (MO ohm,-½ wall) ...... . . . ... . .
l\lystery l'ack . . .. ....... .. . .. . . . .. .... . . .
Dial Un ll (Pulser) , .. ......... . . . .. . .... .
Miscell&neoas Parts
Part No.
32-3097
30-1115
31-6288
30-4519
33-150339
41-8016
38-9704
Bezel AHembly (Cabinet) .. . ......... ... . . 38-9732
Bezel Screws- . . . . . . . . . . . . . . . . . . . . •. . . . •. . W •1885
Cable (Tuntnr Drum) ....... .. . ... ... . .. . Sl -2315
Cable (Pointer) . ....... ... ...... . . .. . . .. . 31-2320
Dial . . .. .. .. . .. . .. .. .. .. .. . •. . • .. .. .. .. . 27-5428
Dial Point er . . . .. .. • . .. . .. . . . .. • ..... . . . . 56· 1033
Disc (Tuntnr) ... .. .. .... ... . .. ....... . ... 27-4768
Disc (Volume) . .. .. ...... .... ... .. .. .. . .. 27-4765
Disc (RallJle Switch) . ......... .. ....... .. . 27-4767
Disc (Tone Control) .... ... .. .. .. . .. . .. . .. 27-4764
Pflol J,amo Assembly ....... . ...... ... .. . . 38-9694
.Pilot Lamp Assembly (Dial) ......... .. .. 38-9711
Pilot Lamp Assembly (Tabs) . . .. . •, •.. . .. 38-9712
Socket (4 prong) ........ ....... ......... . 27-6044
Socket (5 prong) ..... . ....... .. ..... .. .. . 27-603,
Socket (6 prong) .................. ... .... 27-6036
Socket (7 pronr) Octal. ................ .. 27-6057
Socket (6 prone! Octal. . ... . .. . •.... . . . . . 27-60811
Socket (7 prong) Octal. ........ .. .... . ... 27-6099
Speaker .. .. . . . . . .. .. . .. . .. . .. .. . .. .. . .. 36-1450
Rorlng (.Tuning Cables) . . ..... .. . . . . .. .. .. 28-8913
Washer (Keyed Washe r Tunlna Dl ac) . ..... 58-1029
Washer (Spring Washer Tunlna Disc ) ... . .. 6717
Mystery Control Unit
t::I &;e~s·::::::::::::::::::::::::::::
Cap Tuning Disc .. . . .. •. .. . . .. • .•... .... .
Disc (Tunlnr) ...... .. . ...... . .. . .. .. .. . .
Pulser Assembly . . . ... ... . . .. .•••... .. . . .
Stop (TunlllJI Disc) .... ... ... , .......... .
Socket 14 prone ) ............. . ...... .. .. .
Screw (Ftn1er Stop) ............ . ...... . ..
Spacer (FlllJler Stop) ...... .. ........... . .
56-1140
W-2138
27-4793
27-4792
38-9704
27-4794
27-8119
W-2139
27-4195
Mystery Control Unit Diagram
FIG. 1-Model 39-116 Part Locations Underside of Chassis
philcoradio.com

.:··1.
(i) ANT. (2) ANT.
RANGE 1 RANGE 2
l
if(,)"'
l~ ~RANGE3
@2 ""· A
!'ANGE, A1
A11
A10
~I-D!lt'f .
T
I.F.=470 KC.
"'
z
;::
~
148.A 27A 14.n. 13.n.
=NOTE=
SWITCHES SHOWN IN POSITION No .1 (REMOTEVROM REAR OF
CHASSIS, BOTTOM. VIEW,
LETTERS INDICATE POSl'r lON OF SWITCH WAFERS FROM CENTER
OF CHASSIS .
SOLID AREA INDICATES REAR OF SWITCH WAFER .
SHADED AREA INDICATES FRONT OF SW ITCH WAFER.
3 2
<
a
0
0
,;
"'
85.n.
YtLLOW
8LIICK
LESS .l.n.
&LACK
77
0 0
40 DIRECTION OF ROTATION
FROM REAR OF SWITCH . ®-r ·os..i:L--------1-----<ilV\A/V\N-------------+-------------------------J
•
FIG. 2-Model 39-116 DiagrallD and Socket Voltages
See Ballettn 110 A for 39-55 Sche,aatie and Part. Lilt.
Socket Voltage Measured for Socket Contacts to Chassis, Line VoJltage 115 VAC, Volume Minimum, Range Selector (Broadcut)
ALL DOTTED LINES REPRESENT
MECHANICAL CONNECTIONS
BETWEEN PARTS.
philcoradio.com

Page 6 PHILCO Service Bulletin No. 310
13ALB,C
MODEL3~ 33AeoTTbt!J
rii~~NlER IF.
VOP 7 8ATOP OUTPUT
~
4A,e~ii\L®
8BBOTTOM TRANS. Q
V
STEPPER
UNIT 0 ~
Q1G 2ND. DET.
A.V.C.
ST.AUDIO
@ MOD151:icrs
7 @4--MODEL 39-116
ONLY
2 GANG TUNING COND.
QQ
vv
MODEL 39-55
~
THYRATRON
d 0 {I~ ~"°""~ 191 /10A
Q._____,-0-..;~@ 2~MODtL 39-11
IN MODEL 39-55
MOTOR
TRANS.
POWER
TRANS.
FIG. 4-Locations of Compensator-Model 39-55 and 39-116
Adjusting Control Frequency Amplifier
The Mystery Control receivers are shipped with five (5) dif-
ferent control frequencies which range from 350 to 400 K.C. These
are identified by code numbers appearing on the serial number
ticket and on the rear of_the chassis. These code numbers and
frequencies are as follows :
Code 5-355 K.C.
Code 6-367 K.C.
Code 7-375 K.C.
Code 8--383 K.C.
Code 9-395 K.C.
The purpose of the different control frequencies is to prevent
interaction between two Mystery Control receivers which are on
the same floor or are exceptionally close together. When several
Mystery Control receivers are to be located close together, it. will
be necessary to use different control frequencies to avoid inter-
action between the receivers . In order to prevent interaction
between· receivers, there should be a difference of 20 K.C. between
their control frequencies .
If three receivers are to be operated at the same time and are
closely situated, it will be advisable to adjust the control frequency
of the first set to 355 K.C., the second set to 375 K.C. and the
third to 395 K.C.
When realigning or changing the control frequency of the
Mystery Control circuit, a Philco Model 077 Signal Generator with
a coil of wire (about 4 or 5 turns-12" in diameter) attached to
the output terminals is required. The leads between the coil of wire
and Signal Generator should be long enough so that the coil of
wire can be placed near the large secondary inductor in the bottom
of the receiver cabinet.
With this apparatus, the Control Frequency is adjusted as
follows :
1. With the temporary coil of wire in the center of (or
near) the secondary inductor, the control frequency to
which the Mystery Control Amplifier is tuned can be
determined by tuning the Signal Generator between 350
and 400 K.C. When the Signal Generator is tuned to
the control frequency, the Thyratron (2A4G) tube will
glow (blue haze). If this frequency is to be used, leave
the Signal Generator indicator at this point or turn the
indicator to any other frequency desired between 350 and
400 K.C.
2. When the control frequency is selected, turn the sensi-
tivity control (117) in Model 116 an<! (89) Model 55
located on the left rear of the chassis-towards the posi-
tion marked '.'extreme." Using the 2A4G Thyratron
tube as a resonance indicator, adjust padders (103),
(115), (119) in Model 116 and (74), (85), (90) in
Model 55 for maximum signal. This will be indicated
by the brilliance of the glow in the 2A4G Thyratron
tube. As the padders are adjusted , gradually turn the
sensitivity control to the "near" position or reduce the
output from the Signal Generator. When the padders
are correctly adjusted to maximum, the Thyratron will
glow with the sensitivity control (117) at the "near" posi-
tion and with a very weak signal from the Signal
Generator.
3. Next, adjust the padding condenser (121) in Model 116
and _(92) in Model 55 on the secondary inductor located
in the bot,tom of the receiver. The padding condenser is
located in ·one corner of the secondary inductor and is
encased in a cardboard container . This padding condenser
should be carefully adjusted for maximum glow in the
2A4G tube. Use the weakest signal possible from the
Signal Generator that will cause the 2A4G to glow.
Also, have the sensitivity control as close as possible to
the "near" position. Extreme care should 1:1eused in
adjusting the padder to the exact point of resonance, as
the secondary inductor is a very sharply tuned circuit.
After adjusting the circuit, remove the Signal Generator
and loop from the receiver.
4. The Mystery Control unit is now adjusted as follows:
A. Dial any one of the stations indicated on the remote
unit by pulling the selector to the "Stop" position.
Then, as the dial is released at the "Stop," press
the "Stop" down and hold it in this position.
B. Holding the "Stop" in this position, bring the Mystery
Control unit close to the receiver. Using the padding
wrench, tune the padding screw (126) located on the
bottom of the unit until the 2A4G Thyratron in the
receiver glows at full brilliance.
Now, turn the sensitivity control on the receiver
towards the "near" position until a point is reached
where the 2A4G tube almost stops glowing. Then,
readjust the padder (126) of the unit again for maxi-
mum brilliance in the 2A4G tube. The Mystery Con-
trol unit should now be adjusted to the same fre-
quency as the control frequency in the receiver .
PHILCO RADIO AND TELEVISION CORPORATION
Parts and Service Division Philadelphia, Pa.
Sept. 1938 Printed in.U. S. A.
philcoradio.com