Motorola 52B2U Schematic

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Product Information:
Model:52B2U
Manufacturer:Motorola (Galvin)
Description:HS-305

Schematics Content:

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Page 1:

PAGE 23-44 MOTO
MODELS 52B1U, 52B2U
GENERAL INFORMATION
TYPE - Three-power (AC/DC, Battery) portable radio re-
ceiver. Four miniature-type tubes and a selenium
rectifier are used in a superheterodyne circuit.
TUNING RANGE - 535 to 1620 Kc IF - 455 Kc
'POWER SUPPLY - Operates from ll7V AC/DC (15 watts)
or from the following batteries:
Two 1-l/ZV size "D" flashlight cells
or Burgess Z '
one 67-1/zv "B" battery
or Burgess K45
TUBE COMPLEMENT - Type Function
lR5 Converter '
lU4 IF Amplifier
1U5 Det, AVC Sz lst AF Amp
3S4 Power Amplifier
Rectifier Selenium type -for
AC/DC operation
FIGURE I. 52B1U RECEIVER
OPERATIIG INSTRUCTIONS
TO REMOVE LOWER HOUSING. Insert a large coin into
the fastener on the bottom of the receiver (see Figure 1 for
location), and rotate it kzounterclockwise until the housing
is released. Then pull off the housing,
TO REPLACE LOWER HOUSING. Make certain, when the
lower housing is assembled to the upper portion of the set,
that the fastener is on the side of the housing which faces
the speaker. Rotate the fastener clockwise until the hous-
ing is looked into place.
HOUSE CURRENT OPERATION. The power cord is located
inside the cabinet and can be reached by removing the lower
housing. Uncoil the line cord from its retainer and pass it
through the slot in the end of the housing. Plug the cord into
any 117 volt AC or DC power outlet, Reverse the plug in
the outlet if the receiver does not operate from DC power.
When operating from AC, reception may sometimes be im-
proved by reversing the power plug in the outlet, It is not
necessary that batteries be nistaxled if the receiver is to be
operated only from house power lines.
BATTERY OPERATION. Remove the lower housing and in-
stall batteries by following the instructions onrthe label lo-
eatea msn-me me musing, fn- refer to Figure z. Plug me
power line cord into the receptacle on the chassis, or the
receiver will not play from batteries. If the radio is to be
operated for a long period of time from house power lines,
or is to be placed in storage, remove_ the batteries and keep
them in a cool place. XMPORTANT: Never 'leave low or
run-down batteries in the receiver, as they will leak or
swell and damage it,
CONTROLS. The volume control and power switch are com-
bined and are operated with the VOLUME knob (see Fig-
ure X). Select stations with the T`UNING knob. The mark-
ings around the TUNING knob can be read in kilocycles by
adding one zero to the figures.
ANTENNA. A Ferrite Magnetic Iron Core Antenna is built
into this receiver. Because of the slightly directional char-
acteristics of the built-in antenna, reception from some
stations may be improved by rotating the receiver. In ex-
tremely noisy locations, rotate the set until minimum noise
and maximum signal pickup are obtained.
BATTERY REPLACEMENT, If low volume or fuzzy tone is
noticed when operating from batteries, replace the flashlight
cells. Normally, the 67-l/2 volt "B" battery will last for 3
or 4 changes of the flashlight cells. compiete battery re-
placement instructions will be found inside the lower hous-
ing of the receiver, or refer to Figure Z, NOTE: The Con-
dition of the batteries will not affect operation of the re-
ceiver from the house power lines.
O John F. Rider

Page 2:

MOTORQLA PAGE 23-45
H" MODELS 52B1U, 52B2U,
'SERVICE NOTES
The ehassis of this receiver is isolated from the AC
power line circuit by a capacitor-choke assembly to elimi-
nate the shoek hazard when handling the receiver. How-
ever, as an additional precaution when aligning or servicing
the receiver from Ac, an isolation transformer should be
inserted between the power line and the chassis.
The tubes are exposed when the lower housing is re-
moved. It is not necessary to remove the chassis to re-
place tubes.
TO REMOVE THE CHASSIS FROM THE CABINET;
l. Remove the lower housing (see Operating Instructions).
Z, Pull off the knobs.
3. Relnuve the two hex head screws under the knobs,
4. Pull outward on the two studs which hold the handle and
lift off the top housing,
ALIGNMENT
NOTE: The receiver may be operated either from batteries
or from the commercial power lines during alignment. If
AC power is used, it is recommended that an isolation
transformer be placed between the power line and the re-
ceiver. If an isolation transformer is not available, con-
neet thevlow side of the signal generator to B~ through a .1
1. Connect a law range output meter aei-oss the speaker
voice coil-
z. Connect the 1ovv side of the signal generator to B>>.
3. Set the signal generator for ioo cycle, 30% modulation.
4, Turn the receiver volume control to maximum.
5. Use a srnau fibre screwdriver for aligning the xr and
diode transformers.
6. Adjust the signal generator output to produce ?40 volts
(.05 watts) across the voice coil, As stages are aligned,
reduce the generator output to maintain the .to volt level.
to avoid overloading the receiver.
7. see Figure 3 for adjusting locations and the following
chart for procedure.
ALIGNMENT CHART
DUMMY GENERATOR GENERATOR GANG
STEP ANTENNA CONNECTION FREQUENCY SETTING ADJUST REMARISS
IF ALIGNMENT
1. .x mf Grid of Conv Ful1Y 1. 2 F1 3 Adiusi fm' m=>?imUm~
(pin 6, IRS) open (IF cores)
RF ALIGNMENT
Z. .1 mf Grid of Conv Fuuy 4 (Osc) Adjust fur rnaxirnurn.
(pin 6, IRE) open
3_ _ Install batteries in ehas
sis, leaving output mete
Connected to speaker.
4, Radiation Tune for 5 (Ant) Adjust for maximum.
*Connect generator output across 5" diameter, 5 turn loop and couple inductively to receiver loop. Keep loops at least
(C) John F. Rider

Page 3:

PAGE 23-46 MO]'_OROLA _ _ __ __
MODELS 52B1 U, 52B2U,
B BATTERY
LOOP
FIGURE 2 REAR VIEW OF RECEIVER
IF PRI -- IF AMP
FOR BATTERY OPERATION
PLUG LINE CORD INTO
RECEPTACLE ON CHASSIS
LINE CORD HERE
NOT IN USE.
IF CONV DIODE OET~ PWR AMP
IF SEC ` IZIIHIIHNUHIJHHHI IHIWLiiii!If!1'!!lff!lf?Flf!}ll1'1
FIGURE 3. TUBE AND TRIMMER LOCATIONS
(C) John F. Rider

Page 4:

'A' BATTERY
AMP
B BATTERY
STRIP
FIGURE 4. PARTS LOCATIONS
9 John F. Rider

Page 5:

MODELS 52B1U, 52B2U,
,, _ fa -? was
9 John F. Rider

Page 6:

MODELS 52B1U, 52B2U,
PARTS LIST
NOTE: When ordering parts, specify model and chassis number of set in addition to part number and description of part.
Ref . Part 1,151 Be! . Part List
No . Number Descrlgt lon Price N0 . Number Description Price
CHASSIS PARTS - ELECTRICAL Transformers
- 'I'-1 24K6l1438 IF transformer (green dot) :
Capacitors 455 Kc; complete. . . . . . . . . . . 1.35
C-3 21Rl1561l Ceramic , disc: 10 ,000 mai 450V _25 T-3 2513611377 mtput transformer . . . . . . . . . . 1 .05
C-4 2111115593 Ceramic , disc: 47 mmf 50011. - . 15
c-5 1111490232 11?1<1e<1 , paper ; 47 ,ooo mmf 4oov .25 Pi" 1-1"
C-7 2lRll561l Ceramic , disc : 10 ,000 mai 450V .25
c-s 2lK691992 ce;-.ne _ nun lplez zooo , 100 , CHASSIS PARTS - IIECHANICAL
c-9 211101029 cei-use , 1-use = 1500 mmf soov .25 3511563 50112 . Welker: fibre; includes
350 mg/]_0y_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 3 _lo 43A6920l2 Bushing, strain relief: llne cord
C-12 8119817 Paper = .oz nr 1oov. . . . . .25 W" 'ith 43K592?13) ~ - - ~ - - - - - - - - - -?5
424620012 Clip, baffle retaining (mts baffle
EE""EB191o92 seen: 191- , selenium: mu- 42320055 0111> . electrolytic nts . . . . . . . . . . . . .10
,,.,e, 55 "________________ L40 428485548 Clip, IF trans mtg.............doz .20
Choke I1 Cagacitor 13A82022l Cloth, grille (on spkr baffle) . . . . .25
B-2 24.K611433 Choke lr .05 mf paper capacl- 3010511437 Cord , line; with plug; 6 ft long. . .85
t0r,____,__________________ _40 l4A6l1424 insulator, rectifier: fibre (under
gif selenium rectifier)...........doz' .40
L-l 243611428 Antenna l..oop: with core . . . . .70' 3933020 Lug _ s?1?e,- ing (bngery ??n?,?g -in ' `
?_;; ke 24B61l429 Oscillator coil. . . . . . . . . . . . . .90 "Au bgttery I-et5j_ne1~)_ _ _ _ _ _ _ _ _goz _20
exch 3 '70 43K6920l3 Retainer , strain relief: line cord
?r socazoma spelken 3?1/2 PI; 3 'Z ?h' 4lK680029 Spring, battery contact (111 "A"
VC; less output trans. . . . . . 3.75>> bnttery __et________) _ _ _ _ _ _ ___ _ _ _ _ _dn _zo
exch 2 'so 9K600976 Socket _ tube: mlnlature; 7-prong . . . 15
Resistors 3lK611298 Strip , "B" battery terminal : :ith
iii leade... ...-....~-....-..-..... .35
Note: All resistors are insulated, carbon type
unless otherwise specified. CABINET PARTS
H-1 6112122 4-7 mes 20% 1/2l.......doz 1.20
R-2 6116031 100,000 10% 1/21, , _ _ _ _ _d?? 1_g0 464620235 Button, plug (ln top housing) . .doz .20
R4 636477 15,000 10% 1/21. _ _ _ _ _ _ ,491 1_20 13A61l52l Cloth, grille (on chassis insulator) .25
B-4 6112109 10 nel! 20$ 1/2| _ _ _ _ _ _ _ _??? 1_20 3K620214 Fastener , locking (locks lower
R-5 6112118 3.3 neg 20% 1/Zl.......doz 1,20 . houslng)......................d0z .35
R-7 632109 10 neg 2U$ 1/2|..__,,__.-10; 1_g0 _ locklug fastener................. 5.80*
3-3 6|\2122 4 _1 ,eg 201, 1/2g_ _ _ _ _ _ _gn 1 _gg 1515611323 Housing, top: less handle and studs 3.80*
'll-9 6116004 l neg 20% 1/21. _ _ _ _ _ _ _ _dgz 1.20 lB6l1479 Insulator, chassis: fibre; sith
3-10 6|1211B 3_3 |93 20; 1/2|_ _ _ _ _ _ _dug 1_20 grille cloth (lnslde top housing) 1.00
11-11 615577 2700 10$ 1/21, _ _ _ _ _ _ _ _ _.in 1_20 36C6l1430 Knob, control (volume). . . - . . . . . . . . .45
s-12 1111620031 Ilre wanna , flexible: 150 361611431 Klwh . ??n?r?1 (twins) - - - ~ - - - - - - -45
Ohlls 4l.................... .35 41A6ll538 Spring, compression (on handle mtg
gm; 10y___________________ _50 46A61l497 Stud, handle mtg: less spring..." .15
_ 11-14 6116015 220,000 201. 1/ 21. . . . . . .doz 1 .20 4K601456 "Sher . "C" (011 handle Its
B-16 6?G432 270 101, 1/2]_ _ _ _ _ _ _ _ _dag 1_30 021577 Washer , "C" (locklng fastener
11-13 $35583 27 101; 1/2'_ _ _ _ _ _ _ _?|?z 1 _zo 4A620230 Washer , fibre (locking fastener
451706 Washer , flat: 3/8 x .203 x .033;
Svltch steel (locking fastener ntg)per/c .50
?:T' 405511423 |1?|;"~y "1??h _ 557; (AC/pg _ 6620324 Washer , shoulder: flhre (chassis
battery selector).......... 1.15 lf! tv ??P h?\lS1ll?)>>....-.....d?z .15
PRICES SUBJECT T0 CHANGE WITHOUT NOTXCE
*P\u| Federal Excise Tax At Current Rate
(C)John F. Rider

Page 7:

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Rider
6 John F.

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