Technics SA-EH770 User manual

AD0104055C3
Tuner/Amplifier
SA-EH770
Colour
(S)...................SilverType
Areas
(GC).................Asia, LatinAmerica, MiddleNearEast and Africa.
(GN).................Oceania.
SPECIFICATIONS
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1. BeforeRepairs
1. Turn off thepowersupply. Using a10 , 10 Wresistor, connect bothendsof
powersupplycapacitors(C701, C703 and C702, C704) inordertodischargethe
voltage.
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2. Beforeturning thepowersupplyon, aftercompletion ofrepair, slowlyapplythe
primaryvoltagebyusing apowersupplyvoltagecontrollertomake surethat the
consumedcurrentat 50 HzinNOSIGNALmodeshouldbeshownbelowwith
respecttosupplyvoltage110/240 V.
Powersupply
voltage AC110 V AC240 V
Consumedcurrent
50 Hz 200 ~700 mA 100 ~350 mA
2. Protection Circuitry
Theprotection circuitrymay have operatedifeitherofthefollowing conditionsis
noticed:
- Nosound isheard whenthepowerisswitchedON.
- Sound stopsduring aperformance.
Thefunctionsofthiscircuitryistopreventcircuitrydamageif, for example, the
positive and negative speakerconnection wires areshorted, or ifspeakersystems
withanimpedance less thantheindicatedratedimpedance ofthisunitareused.
Ifthisoccurs, followtheprocedures outlinedbelow.
1. SwitchOFF thepower.
2. Determinethecause oftheproblemand correct it.
3. SwitchONthepoweronce again.
Note:
Whentheprotection circuitryfunctions, theunitwill notoperate unless thepower
isfirst switchedOFF and thenONagain.
3. Accessories
- AC powersupplycord for (GC) area
(RJA0019-1X)................................1pc.
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- AC powersupplycord for (GN) area
(RJA0035-X)..................................1pc.
- AMloop antennaset
(RSA0022-L)..................................1pc.
- FMindoor antenna
(RSA0006-J)..................................1pc.
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- Speakercords
(REE0853).....................................2pcs.
(REE1057).....................................2pcs.
- Remote control transmitter
(EUR7702060)..............................1pc.
- Remote control batteries
(R6/LR6, “AA”, UM-3)....................2pcs.
Note:These areavailableon sales route.
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- Powerplug adaptor for (GC) area only
(SJP5213-2)..................................1pc.
4. Location of Controls
5. Operation Checks and Component Replacement
Procedures
Note:
Thecontents ofthissection describes for Europe. Soplease use thissection as a
reference.
- Thissection describes procedures for checking theoperation ofthemajor
printedcircuitboardsand replacing themaincomponents.
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- For reassemblyafteroperation checks or replacement, reverse therespective
procedures. Special reassemblyprocedures aredescribedonlywhenrequired.
5.1. Checking fortheACINP.C.B.
- Check theAC INP.C.B. as shownbelow.
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5.2. Checking fortheoperation P.C.B.
- Followthe(Step1) -(Step3) ofitem5.1.
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- Check theoperation P.C.B. as shownbelow.
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5.3. Checking forthemain P.C.B.
- Followthe(Step1) -(Step3) ofitem5.1.
- Followthe(Step1) -(Step6) ofitem5.2.
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- Check themainP.C.B. as shownbelow.
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5.4. Replacementfortheregulatortransistor
- Followthe(Step1) -(Step3) ofitem5.1.
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5.5. Replacementforthepower IC
- Followthe(Step1) -(Step3) ofitem5.1.
- Followthe(Step1) -(Step6) ofitem5.2.
- Followthe(Step1) -(Step10) ofitem5.3.
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