6D-820
985253
BULLETIN
Chevrolet
UNITED MOTORS SERVICE
DIVISION OF
G E N E R A L MO TO RS CORPORATI ON
8-29-47
1
Date:
Page
GENERAL OFFICES—DETROIT
A uto Ra d io Bulletin
Supersedes
Issue
of
12-1-41
SUBJECT— SERVICE INSTRUCTIONS
Chevrolet Model 985253 Auto Radio
GENERAL
Mounting - Custom 1937 Chevrolet
Type - Two Unit Set
Tubes - Six
Speaker - 5½" Dynamic
Tone Control - Mounted on Header
Speaker
Intermediate Freq. - 262 Kc
Tuning Range - 540/1560 Kc
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ALIGNMENT PROCEDURE
To properly align this receiver, a calibrated Test Oscillator or Signal
Generator and Output Meter or Output Indicator are required. All adjust­
ments should be made with the Volume Control set for maximum volume, keep­
ing the Signal Generator output at minimum for satisfactory output indi­
cation. Tone Control to be in treble position.
Series Cond.
Connection
Set
Adjust
Tune
or
at
To
Generator Receiver Screws
Dummy Antenna
Radio
At
To
At
Obtain
No
2nd IF
.01 Mfd.
262 Kc
Broadcast 5 trimmers
6A8G Grid
Signal
1st IF
4 trimmers
Max.
high freq middle gang
1560 Kc
gang stop Osc trimmer
Signal top&bottom
Output
.0002 Mfd.
Antenna
1400 Kc
Generator gang trimmers
Signal 28 Osc
600 Kc
Generator
padder
Adjust trimmer 2 8 to match car antenna (600 Kc) when set is installed.
en
on
tri
bu
te
d
by
G
Ant, RF & Osc
trimmers
(Printed in U.S.A.)
C
(2301 PD 8-47)
GO:6-65,6-65,6-65SS,31,72: 6
Osc padder
(28)
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on
IF trimmers
8-29-47
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FIG. 2— PARTS LAYOUT— Top View
ld
FIG. 3— PARTS LAYOUT— Bottom View
BOTTOM VIEW OF TUBE SOCKETS
VOLTAGE READINGS BETWEEN
SOCKET TERMINALS AND GROUND
on
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on
WITH D.C.VOLTMETER HAVING
RESISTANCE OF 1000Ω PER VOLT
C
Date:
Page
6D-820
985253
O
BULLETIN
Chevrolet
UNITED MOTORS SERVICE
BULLETIN
Chevrolet
DIVISION OF
6D-820
985253
G E N E R A L MOTORS CORPORATI ON
Date:
Page
GENERAL OFFICES—DETROIT
tri
(Printed in U.S.A.)
on
(OVER)
C
(2301 PD 8-47)
bu
te
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by
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en
e
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ps
on
FIG.
1— CHEVROLET
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MODEL
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985253
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CIRCUIT
DIAGRAM
AUTO RADIO BULLETIN
8-29-47
3
BULLETIN
Chevrolet
Date:
Page
6D-820
985253
8-29-47
4
SERVICE PARTS LIST
E503
E203
E104
G151
GG221
E602
E502
G101
G470
K902
G101
Service
Part No.
RESISTORS
23
A124
35,36,37 A105
38
39,40
A104
41
A3 93
42
A102
43,48,49 A473
44
A474
45
A183
A3 91
46
47,50
A274
50
A271
51
A181
52
A561
53
54
A121
55
B103
67
8528
Illus.
No.
Description
.05 Mfd tub
.02 Mfd tub
.1 Mfd tub
.1-.1-.05-.05 Mfd
.00015 Mfd molded
.00025 Mfd molded
.006 Mfd tub
.005 Mfd tub
.0001 Mfd molded
.00005 Mfd molded
.5 Mfd 160 V hash filter
8-8 Mfd electrolytic
.0001 Mfd molded
Description
124,000 Ohm ½ watt Ins
1 Megohm ½ watt Ins
10,000 Ohm wire-wd 5 watts
100,000 Ohm ½ watt Ins
40,000 Ohm ½ watt Ins
1000 Ohm ½ watt Ins
50,000 Ohm ½ watt Ins
500,000 Ohm ½ watt Ins
20,000 Ohm ½ watt Ins
400 Ohm ½ watt Ins
300,000 Ohm ½ watt Ins
300 Ohm ½ watt Ins
200 Ohm ½ watt Ins
600 Ohm ½ watt Ins
75 Ohm ½ watt Ins
125 Ohm ½ watt Ins
9500 Ohm 1 watt Ins
Vibrator
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12,13,16,
17
18
19
20
21
22,30,32
24
26
29
31
33,34
59
68
Service
Part No.
CONDENSERS
ls
Illus.
No.
C
on
tri
bu
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by
G
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Th
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ps
on
(2301 PD 8-47)