Technics SC-EH760 User manual

AD0004083C3
Tuner/Amplifier
SA-EH760
Colour
(S)....................SilverType
Areas
(GC)..................Asia, LatinAmerica, MiddleNearEast and Africa.
(GN)..................Oceania.
SPECIFICATIONS

1. BeforeRepairs
1. Turnoff thepowersupply. Using a10 , 10 Wresistor, connect
bothendsofpowersupplycapacitors(C701, C703 and C702,
C704) inordertodischargethevoltage.
2. Beforeturning thepowersupplyon, aftercompletion ofrepair,
slowlyapplytheprimaryvoltagebyusing apowersupplyvoltage
controllertomake surethat theconsumedcurrentat 50 HzinNO
SIGNALmodeshouldbeshownbelow.
For (GC) area
Powersupply
voltage AC110 V, 50 Hz AC240 V, 50 Hz
Consumed
current 200-700 mA 100-350 mA
For (GN) area
Powersupply
voltage AC240 V, 50 Hz
Consumed
current 100-350 mA
2. Protection Circuitry
Theprotection circuitrymay have operatedifeitherofthefollowing conditionsisnoticed:
-Nosound isheardwhenthepowerisswitchedON.
-Sound stopsduring aperformance.
Thefunctionsofthiscircuitryistopreventcircuitrydamageif, for example, thepositive and
negative speakerconnection wires areshorted, or ifspeakersystemswithanimpedance less
thantheindicatedratedimpedance ofthisunitareused.
Ifthisoccurs, followtheprocedures outlinedbelow.
1. SwitchOFF thepower.
2. Determinethecause oftheproblemand correct it.
3. SwitchONthepoweronce again.
Note:
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Whentheprotection circuitryfunctions, theunitwill notoperate
unless thepowerisfirst switchedOFF and thenONagain.
3. Accessories
-ACpowersupplycordfor(GC)area / (RJA0019-X)...........................1
pc.
-ACpowersupplycordfor(GN)area / (RJA0035-X)...........................1
pc.
-AMloop antennaset / (RSA0022-J)...........................1pc.
-FMindoorantenna/ (RSA0006-J)............................1pc.
-Speakercords/ (REE0393)..............................2pcs. /
(REE0984)..............................2pcs. / (REE0985)..............................2
pcs.
3

-Remote control transmitter/ (RAK-EHA28WH)..................1pc.
-Remote control batteries / (R6/LR6, “AA”, UM-3)...........2pcs.
Note:These areavailableon sales route.
-Powerplug adaptorfor(GC)area only/ (SJP5213-
2)...........................1pc.
4. Location of Controls
5. Operation Checks and Component Replacement
Procedures
4

-Thissection describes procedures forchecking theoperation of
themajorprintedcircuitboardsand replacing themain
components.
-Forreassemblyafteroperation checks orreplacement, reverse the
respectiveprocedures. Special reassemblyprocedures are
describedonlywhenrequired.
/
5.1. Checking fortheACINP.C.B.
-Check theACINP.C.B. as shownbelow.
5.2. Checking fortheoperation P.C.B.
-Follow the(Step1) -(Step3) ofitem5.1.
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-Check theoperation P.C.B. as shownbelow.
5.3. Checking forthemainP.C.B.
-Follow the(Step1) -(Step3) ofitem5.1.
-Follow the(Step1) -(Step7) ofitem5.2.
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7

-Check themainP.C.B. as shownbelow.
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5.4. Replacementfortheregulatortransistor
-Follow the(Step1) -(Step3) ofitem5.1.
5.5. ReplacementforthepowerIC
-Follow the(Step1) -(Step3) ofitem5.1.
-Follow the(Step1) -(Step7) ofitem5.2.
-Follow the(Step1) -(Step12) ofitem5.3.
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6. ToSupplyPowerSource
ThisunitSA-EH760 isdesignedtooperateon powersuppliedform system connected. / For
system connections, referto Fig. 6-1.
Fig. 6-1.
WhentheunitSA-EH760 has totestand service alone, use thefollowing method tosupplypower
source.
1. Shortthesection betweenW902APin3and C740 (-) (GND). Refer
to Fig. 6-2.
2. Connect thisunittoanACpowersupplycord. / (Thisunitcometo
stand-bymode.)
3. TurntheunitON.
Fig. 6-2.
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Notes:
Use onlythismethod whenchecking thevoltageetc.. / Incase of
checking operations, use thesystemconnectionstosupplypower
source.
7. Self-DiagnosticFunction
Thisunitisequippedwithaself-diagnosticfunction which, intheeventofamalfunction,
automaticallydisplays acodeindicating thenatureofthemalfunction.
Use thisself-diagnosticfunction whenservicing theunit.
7.1. To displaythemalfunction code
U70 CD:/ U70 DECK:
Automaticallydisplayson thetuner/amplifierwhenamalfunction
occurs. Referto Fig. 7-1.
F61:
Automaticallydisplayson thetuner/amplifierwhenamalfunction
occurs. Referto Fig. 7-1. Fig. 7-1.
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7.2. To returntothenormal display
1. ForU70 CD/U70 DECK
-Press ananyoperation button on thetuner/amplifier.
-To re-displaythecode, switchthepoweroff (POWER
STANDBYbutton), and thenswitchpowerback on again.
2. ForF61
-IfF61 isdisplayed, thepowerwill automaticallybeswitched
off and thestandbyindicatorwill lightup.
-F61 will bedisplayedfor3seconds, and thentheclock will be
displayed.
-To re-displaythecode, switchthepoweron. F61 will bere-
displayed, and thenafter3secondstheclock will bedisplayed
and thepowerwill automaticallyswitchoff.
7.3. Displaycontents
7.3.1. U70 CD/U70 DECK / (displayedautomatically)
-Problemorcondition
Abus-linecommunicationserrorhas occurredas aresultofthe
flat cables being insertedincorrectly, thuspreventing thesystem
fromoperating.
-IfU70 isdisplayedon thetuner/amplifier, thetapedeck orCD
Changercannotbeoperatedbyremote control.
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-Correction Procedure
1. To check forcorrect insertion oftheflat cables.
-Inserteachconnectoruntil you hearaclick.
-Inserttheflat cables at theback oftheunitintheorder
indicated. Referto Fig. 7-2.
Make surethewhite sideofthecables ison yourrightside.
Referto Fig. 7-3. Fig. 7-2.
Fig. 7-3.
2. Breakageoftheflat cables. (Check and replace.)
3. Iftheproblemisnotcorrectedbyitems1and 2above, this
indicates afaultyIC.
SA-EH760:
IC901 (LC8A524A5N28)
SL-EH760:
IC451 (M38504M6200F)
RS-EH760:
IC701 (M38503M2400F)
Check these ICsand replace.
7.3.2. F61
-Problemorcondition
Whenthepowerswitchisswitchedon, itautomaticallyswitches
back off, making itimpossibletoswitchpoweron.
-Correction procedure
FaultyTuner/Amplifier(SA-EH760) outputIC(IC601). (WhenaDC
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voltageisappliedtospeakerterminals.)
8. Type Illustration of ICs, Transistorsand Diodes
9. SchematicDiagramNotes
-Thisschematicdiagrammaybemodifiedat anytimewiththe
developmentofnew technology.
Notes:
S701:
Voltageselectorswitch(VOLT ADJ) / (GC)area only
S901:
PowerStandby/on switch( /I)
S902:
ECO modeswitch(MODE)
S903:
Clock/timer, demoswitch/ (CLOCK/TIMER, DEMO)
S904:
Playtimer/recordtimerswitch/ ( PLAY/ REC)
S905:
FMmodeswitch/ (FMAUTO/MONO)
S906:
Tuning modeswitch/ (TUNING MODE)
S907:
Set switch(SET)
S908:
Source inputswitch/ (INPUTSELECTOR)
S909:
6chdiscrete inputswitch/ (6 CH DISCRETEINPUT)
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S910:
Tuning downswitch(TUNING, )
S911:
Tuning up switch(TUNING, )
S912:
Tuner/band switch(TUNER/BAND)
S913:
Digital superwooferswitch/ (DIGITALS.WOOFER)
S914:
KARAOKEswitch(KARAOKE)
S915:
Echo switch(ECHO)
VR401:
Microphonevolumecontrol VR/ (MICVOL)
VR901:
Volumecontrol VR(VOLUME)
-Indicatedvoltagevalues arethestandardvalues fortheunit
measuredbytheDC electroniccircuittester(high-impedance) with
thechassistakenas standard. Therefore, theremayexist some
errorsinthevoltagevalues, depending on theinternal impedance
oftheDC circuittester.
Nomark
:PowerON(FMorAM)
-Importantsafetynotice:
Components identifiedbymarkhavespecial characteristics
importantforsafety.
Furthermore, special parts whichhavepurposes offire-retardant
(resistors), high-qualitysound (capacitors), low-noise (resistors),
etc. areused.
Whenreplacing anyofcomponents, besuretouse only
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manufacturer´s specifiedparts shownintheparts list.
-Caution!
ICand LSI aresensitivetostaticelectricity.
Secondarytroublecanbepreventedbytaking careduring repair.
Covertheparts boxes madeofplastics withaluminumfoil.
Ground thesoldering iron.
Putaconductivemat on theworktable.
DonottouchthelegsofICorLSI withthefingersdirectly.
-Voltageand signal line
:Positivevoltageline
:Negativevoltageline
:AMsignal line
:AMOSCsignal line
:FMsignal line
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:FMOSCsignal line
:Centersp.drivesignal line
:Surround sp.drivesignal line
:Source signal line
:Micsignal line
10. SchematicDiagram
11. Printed Circuit BoardDiagram
12. Wiring Connection Diagram
13. Terminal Function of ICs
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13.1. IC901 (LC8A524A5N28):/ SystemControl/FL Drive
Pin
No.Terminal Name I/O Function
1CHECK O Clock check signal output
2 LC72 DI O PLL datasignal output
3 LC72 CE O Chipenablesignal output
4 LC72 DO
/ST IIFcountdata/stereodetect signal input
5 LC72 CK O Clock signal output
6RL1 O Speakerselectsignal output
7RL2 O Speakerselectsignal output
8ST/
AV6CH - Notused, open
9SEL
TUNER OTunerselectsignal output
10 SEL/
TUNER ITunerselectsignal input
(Notused, connectedtoVDD)
11 ACIN I Powerfailuredetectsignal input
12 RESET I Resetsignal input
13 X IN I Oscillator connectedterminal
(32.7kHz)
14 X OUT O
15 VSS -GND terminal
16 XCIN I Oscillator connectedterminal (6
MHz)
17 XCOUT O
18 VDD1IPowersupplyterminal
19 KEYTU I Operation key signal input
20 KEY
KARAOKE IOperation key signal input
21 SHREQ I Requestsignal inputfrom
Sound Processor
22 NC(GND) - Notused, connectedtoGND
23 VR
JOGB IVolumecontrol signal input
24 VR
JOGA
25 MICDET I Microphoneconnecting detect
signal input
26 HP SW I Headphoneconnecting detect
signal input
27 RDS
CLK IRDS clock signal input
(ConnectedtoGND)
28 RDS
DATA IRDS datasignal input (ConnectedtoGND)
29REMOCON IRemotecontrol signal input
30 NC - Notused, open
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Pin
No.Terminal Name I/O Function
31
|
37
7G
|
1G
O Gridsignal output
38 NC - Notused, open
39
40
|
45
P1
|
P6
O Segmentsignal output
46 VDD3IPowersupplyterminal
47
|
50
P7
|
P10
O Segmentsignal output
51 -VP I Powersupplyterminal (negative)
52
|
71
P11
|
P30
O Segmentsignal output
72 VDD4IPowersupplyterminal
73
|
77
P31
|
P35
O Segmentsignal output
78 REGIN0 I Area selectsignal input
79 REGIN1
80STANDBY OLED(STANDBY)drive signal
output
81 TIMER O LED(TIMER) drive signal output
82 S.WLED O LED(DIGITALS.WOOFER) drive
signal output
83 LOUNGE - LED(LOUNGE)drive signal
output
(Notused, open)
84 CHORUS -LED(CHORUS)drive signal
output
(Notused, open)
85 MUTE O Muting signal output
86 POWER O Powercontrol signal output
87 /ECO O ECOsignal output
88 MUTE2 O Muting signal output
89 VSS2-GND terminal
90 VDD2IPowersupplyterminal
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Pin
No.Terminal Name I/O Function
91 NC - Notused, open
92
93 RL4 - Notused, open
94 SHCS O Chipselectsignal outputfor
Sound Processor
95 SHDO O Serial communication signal to
Sound Processor (Datasignal
output)
96 SHDI I Serial communication signal to
Sound Processor (Datasignal
input)
97 SHCK I Serial communication signal to
Sound Processor (Clock signal
input)
98 E DET I Unusual condition detectsignal
input
99 CR
TIMER I/O TIME CONSTANTterminal
100 SD I Station detector signal input
from tunercircuit
14. Block Diagram
15. Replacement PartsList
Notes:
-Importantsafetynotice:
Components identifiedbymarkhavespecial characteristics
importantforsafety.
Furthermore, special parts whichhavepurposes offire-retardant
(resistors), high-qualitysound (capacitors), low-noise (resistors),
etc. areused.
Whenreplacing anyofcomponents, besuretouse only
manufacture’sspecifiedparts shownintheparts list.
-The<IA><IB> <IC> marks inRemarks indicate languageof
instruction manual.
<IA>:English, Chinese, Arabic
<IB>:English
<IC>:Spanish
-TheparenthesizedindicationsintheRemarks columnsspecifythe
areas. (Refertothecoverpageforarea.)
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