Marantz SM500DC User manual

SERVICE
MANUAL
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MARANTZ DESIGN AND SERVICE
Using superior design and selected high grade components, MARANTZ Company has created the ultimate in stereo sound.
Only original MARANTZ parts can insure that your MARANTZ product will continue to perform to the specifications for
which it is famous.
Parts for your MARANTZ stereo are generally available within 72 hours throughout the nation via a toll-free line to our
National Parts Depot in California. The sales professionals who take your call immediately refer to their own desk top com-
puter terminal and can quickly determine the availability and price information you require. If for some reason, your order
should exceed our available stock, we usually can instantly provide an alternate replacement part or current delivery infor-
mation. When the order is placed and confirmed, the computer simultaneously generates “hard copy” orders at the
distribution center. As hard copies come directly from the computer to the national parts depot, your requested stock is
assembled and prepared for shipment and placed on the first available carrier for delivery to you. ,
ORDERING PARTS
Phone orders will eliminate mail delays, and we encourage the use of this method. If you order by mail, use MARANTZ parts
order forms which are available from our National Parts Depot located at the following address:
SUPERSCOPE NATIONAL PARTS DEPARTMENT
20525 Nordhoff Street
Chatsworth, California 91311
Phone: [phone]
1-213-998-9333
The following information must be supplied to eliminate delays in processing your order:
. Complete address.
. Complete part numbers.
. Complete description of parts.
. Model number for which part is required (indicate MARANTZ).
. Account number (for account customers only).
OPWN =
Direct consumers will be provided with the current retail prive quotation on available parts in order to advise them of the cost
of the parts and shipping.
OVERSEAS PARTS ORDERING
Parts may also be ordered from the following overseas addresses:
U.S.A. CANADA AUSTRALIA JAPAN
Marantz Company, Inc. Superscope Canada, Ltd. Marantz Australia ; Marantz Japan, Inc.
National Service Dept. 3710 Nashua Drive 32 Cross Street 3622 Kamitsuruma
P.O. BOx 577 Mississauga , Brookvale, NSW 2100 Sagamihara-shi
Chatsworth, CA91311 Ontario, Canada L4V1M5 Australia Kanagawa, Japan
U.S.A.
.
EUROPE
;
Marantz Europe S.A. Marantz France Marantz Audio U.K., Ltd. Marantz Germany GMBH
326 Avenue Louise Bte 32. +4 rue Bernard Palissy 193 London Road Max-Planck-Strasse 22
1050 Brussels 92600 Asnieres Staines, Middlesex : 6072 Dreieich
Belgium France United Kingdom West Germany
Marantz Belgium Marantz Svenska A.B. Marantz Norske A.S.
45 rue Auguste Van Zande Franzengatan 6 Refstadalleen 13
1080 Brussels : 10425 Stockholm Oslo 5
Belgium Sweden ‘Norway
All of the above locations are fully equipped to take care of your total service needs. Because various countries have differing
configuration requirements, it is necessary that you contact the service facility in your particular country. In the event that
there is no service location listed for your country, please contact the nearest facility for the necessary assistance.

TABLE OF CONTENTS
SECTION PAGE
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6.1 Main Amp & Power Supply Assembly (P700) Schematic Diagram and Component Locations .............. 3
6.2 Speaker Switch Assembly (PS00) Schematic Diagram and Component Locations ...................0-. 5
6.3 Headphone Assembly (PWO00) Schematic Diagram and Component Locations ................ ores 5
6.4 Lamp Assembly (PZ00) Schematic Diagram and Component Locations .................c0ceeeuuees 5
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MODEL SM500 DC STEREO POWER AMPLIFIER
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1. ‘INTRODUCTION
This service manual was prepared for use by Authorized
Warranty Stations and contains service information for
the Marantz Model SM500DC Stereo Power Amplifier.
Servicing information and voltage data included in this
manual are intended for use by knowledgeable and ex-
perienced personnel only. All instructions should be
read carefully. No attempt should be made to proceed
without a good understanding of circuitry operation.
The parts list furnishes complete ordering information.
Most replacement parts should be ordered from the
Marantz Company. However, a simple description is
included for parts which can be obtained locally.
3. BLOCK DIAGRAM
FEEDBACK
NETWORK
POSITIVE
PREDRIVER DRIVER
BIAS
CIRCUIT
DIFFERENTIAL
INPUT
NEGATIVE
PREDRIVER DRIVER
DC SERVO
AMPLIFIER
PR AR REGIE
POSITIVE
LOAD LINE
LIMITING
PROTECTION
CIRCUIT
NEGATIVE
2. P.W. BOARDS
As can be seen from the circuit diagram, the chassis of
Model SM500DC consists of the following units. Each
unit mounted on a printed circuit board is described with-
in the square enclosed by a bold dotted line on the circuit
diagram.
1. Main Amp & Power Supply............-
mounted on P.W. Board P700
2. Speaker Switch. ... mounted on P.W. Board PSOO
3. Head Phone...... mounted on P.W. Board PWOO
4, Lamp.......... mounted on P.W. Board PZ00
POWER
METER
POSITIVE CIRCUIT
POWER
SPEAKER
PROTECTION
RELAY
HEAD
TO RCHO—— || PHONES
2
NEGATIVE
OWE, SPEAKERS
SYSTEM 1
TO
RCH
SPEAKER
SYSTEMS
SYSTEM 2
TO
RCH

4. TEST EQUIPMENT REQUIRED FOR SERVICING
This table lists the test equipment required for servicing for the Model SM500DC Stereo Power Amplifier.
Item
Manufacturer and Model No.
Distortion Analyzer
Audio Oscillator
AC Voltmeter
Sound Technology Model 1700B
Use
Distortion Measurements
Sinewave and squarewave signal source
voltage measurements (AC)
; Tektronix Model T932
Oscilloscope oa
Philips Model 3232
Circuit Tester
Waveform analysis and trouble shooting and
ASO alignment
Trouble shooting
DC Voltmeter
Fluke Model 8000 “‘Digital’’ Simpson
Model 313, Triplet Model 801
Voltage measurements (DC)
AC Wattmeter Simpson Modei 1379 Monitors primary power to amplifier
AC Ammeter
Commercial! Grade (1 ~ 10 A)
Monitors amplifier output under short circuit
condition
Line Voltmeter Simpson Model 1359
Monitors potential of primary power to
amplifier ,
Variable Autotransformer
Superior Electronic Co.,
Powerstet Model 116B-10A
Shorting Plug
Output Load
(8 ohms, +0.5% 100 W)
Output Load
(4 ohms, +0.5% 100 W)
Use phono plug with 600 ohm
across center pin and shell
Commercial Grade
Commercial Grade
Adjusts level of primary power to amplifier
Shorts amplifier input to eliminate noise
pickup
Provides 8-ohm load for amplifier output
termination
Provides 4-ohm load for amplifier output
termination
Output Load Capacitor
(0.5 mfd)
Mylar
Provides capacitive load for instability checks
AC Power Control Box
Optional Item. Fabricate in
accordance with Figure 1
Monitors and controls primary power for
amplifier
Amplifier Output Load Box
CL
Optional Item. Fabricate in
accordance with Figure 2
Provides various amplifier loads and can
monitor shorted output
5. ALIGNMENT PROCEDURES
5.1 Idling Current Alignment Procedure
Where to be adjusted: R733 and R734
Adjusted value: 20 mV (20 mA ea.)
’ Procedure
1 With the input of the set placed in Open, set the
power switch to ON.
2 Adjust semi-fixed resistance, R733 and. R734, so
that the voltage of both the ends of R741 and R742
may become 20 mV after 10 seconds.
5.2 Power Meter Alignment Procedure
Where to be adjusted
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Procedure
1 Connect the load resistance 892 to the speaker ter-
minal of the set.
2 Connect the 1 KHz from SG to input.
3 Set the power switch of the set to ON, increase the
SG output, and adjust the speaker output to be-
come 50W — 822 (20V).
4 Adjust RX07 and RX08 so that the meter may indi-
cate 50W (82).

DIAGRAM AND COMPONENT LOCATIONS
6.
6.1 Main Amp & Power Supply Assembly (P700) Schematic Diagram and Component Locations.
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6.2 Speaker Switch Assembly (PS00) Schematic Diagram and Component Locations
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6.3 Headphone Assembly (PW00) Schematic Diagram and Component Locations
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6.4 Lamp Assembly (PZ060) Schematic Diagram and Component Locations
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7. EXPLODED VIEW AND PARTS LIST
@ [C01-99] Front Panel
002B
006B
011B
© (U) for U.S.A.
® (N) for Europe
® (A) for Australia
© (F) for Japan
1232063400 | Front Panel Assembly 208H154060.| Knob, Push Switch
123Z063410 | Front Panel Assembly 51300306B0 | P.H. Tapped Screw P3x6
1232063010 | Escutcheon, Front Panel 51300306B0 | P.H. Tapped Screw P3x6
1232063110 | Escutcheon, Front Panel
403H067010 | Cap
403H063020 | Escutcheon
208H259010 | Bushing, Push Switch

e@ [C02-99] Lid. (Top and Bottom Cover)
PART NO.
208H257010
51260408Z0
51260408U0
2991259010
1232257010
403H057010
51280308B0
DESCRIPTION
Lid, Top Cover
B.T. Screw B4x8
B.T. Screw B4x8
Bushing
Lid, Bottom Cover
Leg
B.H. Tapped Screw B3x8
PART NO.
51280308B0
213H118020
213HO56020
2932861110
2578861010
e@(U) for U.S.A.
e (N) for Europe
e (A) for Australia
e (F) for Japan
DESCRIPTION
B.H. Tapped Screw B3x8
Spacer
Buffer
Label Top Cover
Label Bottom Cover