Denon PMA 425R Service Manual

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D E N O N Hi-Fi Integrated Stereo Amplifier

SERVICE MANUAL
MODEL PMA-425FI

INTEGRATED STEREO AMPLIFIER

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CONTENTS
OPERATING INSTRUCTIONS ................................................................... 2-7
REMOVAL OF EACH SECTION .................................................................. 8 9'
BLOCK AND LEVEL DIAGRAM ................................................................... 19:
METHOD OF ADJUSTMENTS .................................................................... 11'
SEMICONDUCTORS ....................... . . . 12. Ta
PRINTED WIRING BOARD . . a ..................... . . 14. 15'
PARTS LIST OF P.W.B. ASS'Y ..................... 16. 17
EXPLODED VIEW OF CHASSIS AND CABINET ................... . . I 13
PARTS LIST OF EXPLODED VIEW ............................ .............. 19
WIRINGDIAGRAM .......... , 20
SCHEMATIC DIAGRAM ................................... ' ................. " ................. r. ; .. 21

NIPPON COLUMBIA 00.. LTD.

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CAUTION

RISK or ELECTRIC SHOCK
Do NOT OPEN

CAUTION: TO REDUCE THE RISK OF ELECTRIC SHOCK.
DO NOT REMOVE COVER (OR BACK). NO USER SERVICE-
ABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED
SERVICE PERSONNEL.

The Ilghlning flash wIIh arrowhead symbol, within an equilaieiel Iriangle.
Is inlendsd to aim Ihe user to the pmunca D' uninsulaisd dangerous
voltage wllhin the produci's enclosure iIiaI may be of sufficient
magnitude lo constitulu a risk of alsclric shock to pursoni.

The exclamalion polnl wlthin an equilateral lriangla inlended to alert the
user in ma presance of imporianl operaling and mainlenanca (servicing)
inltrucliuns In ma Ilieraluro accompanying the appliance,

WARNING: TO REDUCE THE RISK OF FIRE 0R ELECTRIC SHOCK. DO NOT EXPOSE THIS
APPLIANCE T0 RAIN 0R MOISTURE.

- Eon u.s.A. l CANADA MODEL ONLV

o POUR LE MODELE OANADIEN UMOUEMENT

CAUTION ATTENTION

mun FREVENIR LES cnocs ELECTRIOUES NE Ms UTILISER
CETTE FICHE POLARISEE AVEC uN PROLONGATEUR UNE
PnIsE DE CDURAHY cu uNE AUTRE SOETIE DE COURANY,
yufi sl lES LAMES PELWENY ErilE INSEREES A Form SANS
EN LAISSER AUCUNE PARTIE A DECOUVERT

TO PREVENT ELEcmic snocx 00 NOT usE mls IPDlAs
nlem PLUG wml AN EXTENSION CORD. RECEITACLE on
OTHER OUTLET UNLESS THE BLADES CAN 3E FULLV IN-
SERTED TO PREVENT BLADE EXPOSURE.

e NUR ran EUROPAISCHE MODELLE

xmmmoralarun.

DI. DEMON Elaclronro [3th
nalmarrun. 12
4am mung-n

Enlan a rural .rilrnponaur aaii aas in aimr nodununonnlonpng Miami-hula cam m mum-cm Voracnnlun lrlr ron und
Eer - mil flu . .. aaa/laaa an Air Pun ond Wm (H. a.
deal Iniwvicm,

DECLARATION OF CONFURMIW DECLARACIDN DE CONFORMIDAD
Wodesura undorour sola lflmlihllflv mar inn Blvd-Au lo wflmh inie nacl mo. in» noanra xnlullu
doclaranon rein... is carrier ry wirn ma lollowing nonaard. al a rim rclmncia
94550:; 9455an ENwsfis: end Eusosasa mini-I amnaam

.. Enssola, inseam menus-z y ENMHJ.
UBEREINSTIMMUNGSERKURUNO

wrr anilaran lulu! ununrvolanlwoilung. an: an... mam .aldaa EENVORNIGHEIDSVERK-LARING
aicn dim MAIN. din wn

ENGwIJ. airman. Emosen and Emma,

DECLARATION DE CONFORMITE

-Nalal alclarona aoua Mllll uula rupmabim ou- ravparan, auouei
on raw- clu- dicI-ulmn, ui conlnrme m illnfialdl suiyarua:
Euswia, Eussuzo. Enema 2 « ENSUSGEA

DICHIARAlIONE DI CONFORMITA

,vlcniarlarrm can pim maponubilila one oua o pradurld ai quala la
lwnrl alonlaruloua "lull A apolonn - mil-Ml norm-ma,
mason, Emma. Erma» e mm ,

ad our ul- Broaden
a ponlorrna eon Ina

an on ocuauii.
waarpp du- wklvinn bull-liking mi: in warr-nal-rnrrrlng ll moi da
voipanda minim

Enmia. Enmzo, macaw-z an Encosas-a,

OVERENSSTAMMELSESINTYG

min-ad nrpaa nail pl mi anmr In dunno alumni. will." dul-
iniyg WI ,unanN lalpnd. murd-
ENmu, ENmio. mm»: on Embraces

DECLAMW DE CONFORMIDADE
Dudwlmnbnoulucl
Manolo coir ponda. m Ian canlorrnlaad. m u

rag ndrnioa
Enasoia, Emma. Eudora u Evacuees a,

I\l

SAFETY INSTRUCTIONS

Bold lnarrucirona - All inc saluly and oparaling
inalruclions shauld be read helnla rna lppllancl la
Opfll'llbd.

Rel-in Inuiuclions - Thu Eel-(y Ind operating
imlluclionl shauld be retained '0 lulu" reference.

Head warnings - All warning: on rile appl lied and
In the operating inalmcliona should In ad grad lo.

Follnw Inlvucllons - AII apamling and use inuluc»
llom would be (allowed.

Water and Malslurs v The appliance should noI by
land nalr Wale! - in! example, near a balhlub,
washbowl, kilchen link, llundrv tub, in I wal

besernoni, or near a Iwimminq pool, and ma like. "

Clru Ind Stands - The appliance should be usa

only willi a can or aland mat is recommended by in. '

manuimum.

An lpplllnca and
cm comblnllinn

mould be mm

mm care. Oillck

:IOW. BXGEBSIVB

Dice. )nd uneven -
aurlreea may cams "
Ihe appliance and can combine an id ouenorn.

Wall or Coiling Mbunllrig - The appliance should be
mounud lo a wall or ceiling only as recommended
by Ihe munulacwlal.

Venillaflon -- Ths appliance Should be Elluamd so
inal its locarion or porilion doe: nor inrorlore win. in
proper venulalion. For example. Ihs appliance
snould not be situated on a bed. sofa, rug, or similar
suriaco lha! may block in. venrilouon openinga; or,
placod in a builr-in inslalialion, such as a buokclsa or
column mat may impede rile now ol ail llrrougn Ihe
yeoliinlion openings

Hell - The Ipplilnu would be diluted Iway flom
heal sources such as radiators, hell reaialara,
slaves. or olher appliancos (including amplifleul
lhal Dmduct hoax.

Pawersoulces-The apvlllnc' should bl connuclad
m a pawn supply only 0' [he lvve described In III-
operaling innrucllona or as marked on me or»
pliencs.

Grounding or Poll ralion - Frans (Ions rnouid ha
Idken ao Ill-l in. grounding or polarrrarion moan. oi
an appliance is our doloaied.

12.

I7,

is.

5.

20.

, moaning - in. appliance ihnuld bu cl
_ rapornrnaindad by ilra manulaclurur.

x mm. grounding ol inc lea

Puwer»Cord Proleerion - Powemupply cords mould
be round so me! they I" no! likely I0 be wulkud an
or pine-nod bv items placed noun or againsl lhdm.
paying panicular allnniidn lo cards a: plugs, con-
voniance recapraoioa. and Ihe polnl where my axii
from The applilnce.

d only I:

. . Power Llnu- An outdoor smenna would b8 localed

Iwa "am power Iinu.

Ouidoor Aniumn Gmundinq - ii an oulaido anlennu

ia ponnecurd lo lilo receiver, be aure lna anranna
gym is grounded m as in prdvlda mma pvotec-
rion againar voluge rurgoa nd burn-up arelic
cnergos. Article am or inc Mano I Eieclrl l Codi,
ANSIINFPA 7o. proyidu lnlorrn on wall ieqsld lo
pvapev grounding ol Ill: mast and supponing slrucr
Wlle I0 In nnlannr
diacharuo unil. aim of grounding wndumnn, loca-
rlon ol InunM-diuhlrgo unlt, connectldn lo
grounding elmrodns, and rodulramanrs lor rne

gmundlug elmroda. Sao Figure A.

NanuIs Parlofla « The power cord or me .ppiianca
alrould be unpluggod ironi in. auilei when loll
unusod lor a long peliud 05 time.

Obiecl and Liquid Enrry - Care should or rain so
lhll obiacia do nol iall and liquid. are run spilled inio
llia enclnaurl ihrougn openings.

Dnrnaga nag rinp Service ~ Tha appliencu abouid
ba serviced by qualified service pelsunnel wnon:

A. The power-supply cord or lire plug has been
damaged; or

a. Obiocla hive lull-n, or liquid naa burl apillad Inlo
lire appliance; or

c. flu appliance has bun expand la rain: or

D. "rlia appliance does nol Ipnur lo operale normalv
Iv or exniblle a marked cncng parlormance; or

E. The appliance nu been dropped. or lilo enclotum
damIlJed.

Servicing -. The unit should not lflempl to seivicl
lha appliance beyond illal described In lhe oparallng
insiruciiona. All diner servicing should in Marrod lo
gualiliad aervica penonnal.

_ HBBV'VWG -

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