Marantz PM 78 Service Manual

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Integrated stereo amplifier

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TABLE OF CONTENTS
SECTION PAGE
1.8PECIFICATIONS ...................................................................................................................................... 1
2.TEST EQU|PMENT REQUIRED SERVICING ......................................................................................... 2
3.IC INFORMATIONS ................................................................................................................................... 3
4.BLOCK DIAGRAM ...................................................................................................................................... 5
5.WIR|NG DIAGRAM .................................................................................................................................... 7
6.SCHEMAT|C DIAGRAM AND PARTS LOCATION (PARTS SIDE) .......................................................... 9
7.EXPLODED VIEW AND PARTS LIST ...................................................................................................... 45
8.IDLING CURRENT AND DC OFFSET VOLTAGE ALIGNMENT .............................................................. 48
9,ELECTRICAL PARTS LIST ...................................................................................................................... 49

Please use this service manual with referring to the user guide (D.F.U )without fail.

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Model PM-68 I PM-78 4822 725 51168

PCS 98 228 First issue 1998.01
214W855010 ACT

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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 equipment are generally available to our National Marantz Subsidiary or Agent.

ORDERING PARTS :

Parts can be ordered either by mail or by Fax.. In both cases, the correct part number has to be specified.

The following information must be supplied to eliminate delays in processing your order :

1. Complete address

2. Complete part numbers and quantities required.

3. Description of parts

4. Model number for which part is required

5. Way of shipment

6. Signature : any order form or Fax. must be signed, othenNise such part order will be considered as null and void.

-USA -CANADA -EUROPE
MARANTz AMERICA, INC. - LENBHOOK INDUSTRIES LIMITED MARANTz EUROPE 5.17.
440 MEDINAH ROAD 533 GRANITE COURT, ROBOX 80002
ROSELLE, ILLINOIS 60172- 2330 PICKEFIING, ONTARIO L1w 3K1 BUILDING SFF2
USA CANADA 5600 .15 EINDHOVEN
PHONE :630 - 307 - 3100 PHONE :416-831-6333 THE NETHERLANDS
FAX :630 . 307 - 2687 FAX :416-831-6986 PHONE : +31 - 4o - 2732241
FAX : +31 - 40 - 2735573
'PHDFESJIGNAL USA - IIFESSIONAL CANADA -TRADING
SUPERSCOPETECHNO LOGIES, INC. Tc ELECTRONICS CANADA LTD. MARANTz EUROPE a.v.
MARANTz PROFESSIONAL PRODUCTS 540 FIRING AVE. P.O,EOX 30002
1000 CORPORATE BLVD., SUITE D BAIE DURFE, QUEBEC Hex 3T2 BUILDING SFF2
AURORA, ILLINOIs 60504 USA CANADA 5600 JB EINDHOVEN
PHONE :530 - 020 - 4800 PHONE 2 514 - 457 - 4044 THE NETHERLANDS
FAX :530 - 520 - 8103 FAX : 514 - 457 - 5524 PHONE : +31 - 4o - 2732241
FAX : +31 - 4o - 2735578
- BRAZIL -THAILAND - HONG KONG------
MARANn BRAZIL MHZ STANDARD co., LTD. FORWARD INTERNATIONAL CORRLTD.
Caixa Postal 21462 746 - 750 WANGBURAPA BANGKOK 15TH FLOOR, REGENT CENTRE,
CEP 04695-970 10200 THAILAND as QUEENS ROAD, CENTRAL. H. K,
Sao Paulo, SP. BRAZIL PHONE :+66 2222 9181 PHONE : +052 521 - oasa
PHONE :oaoo ~ 123123(Discegem Direta Granite) FAX : +66 2225 5071 FAX : +852 521 - 7535
FAX :+55 11 534. 8988
- TAIWAN - MALAYSIA
PAI-YUING co., LTD. , wo KEE HONG ELECTRONICS SDN. BHD.
6TH FL NO, 145 SUNG KIANG ROAD, NO. I 02 JALAN ss 21/35, DAMANSARA
TAIPEI, 10429,TAIWAN ROC. UTAMA, 47400 PETALING JAYA
PHONE :+606 (2) 5221304 - a SELANGOR DARUL EHSAN,
FAX : +856 (2) 5530415 MALAYSIA
PHONE :+50 3 - 7184666
FAX : +60 3 - 7173828
JAPAN Technical \ -SINGAPORE
MARANTZ JAPAN INC. 5 2K 7 7 V J 1* it % *i FORWARD MARKETING (SINGAPORE) PTE. LTD.
35- I , 7- chome, Sagamiono __ 29, LENG KEE ROAD
Sagamihara - shl. Kanagawa A: #5: 1- 220 SINGAPORE I 59099,
Japan 1¢§II fitfiéififitfitfikfi 7 - 35 - 1 PHONE : +65 475 - 4555
PHONE : +81 427 44 7950 515542511 T 150 FAX : +65 475 - 8623
FAX : +51 427 4a 0889 fifiatifiezfiitfia 1 - 11 - 9

SHOCK, FIRE HAZARD SERVICETEST :

CAUTION : After servicing this appliance and prior to returning to customer, measure the resistance between either primary AC
cord connector pins ( with unit NOT connected to AC mains and its Power switch ON ), and the face or Front Panel of product and
controls and chassis bottom. '

Any resistance measurement less than 1 Megohms should cause unit to be repaired or corrected before AC power ls applied, and
verified before it is return to the user/customer.

Ref. UL Standard N0.,1492.

In case of difficulties, do not hesitate to contact the Technical
Department at above mentioned address.

970926ACT
PCS 98 229