Revox B225 Technical specifications

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REI/QX ' . B225
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1.GENERAL
1-1IndexofCOolayercontrols1/i
1*1* 1 Generalcontrols1/1
1*1*2Specialcontrols1/2
1*1*3Rearpanelconnectors1/3
2.
t REMOVALOFASSEHBLIES
2.1Removingthetopcover2/1
2*2Removingtnesidepanels2/1
2.3Removingtheindividualcircuitboards2/1
2*4Removingtheplayermechanism2/1
2®5Removingthedisplay2/2
2*6Removingthepo^er t r ansformator2/2
2*7Removingthedrawermotor2/1
2*8Removingtneoperatingpanel2/3
Z«9Removingtheguiderods2/3
3*CIRCUITDESCRIPTIONS
3.1SERVO1 PC31.759.3103/1
3.1®1Stabilizationofthesupplyvoltages3/1
3*1*2 Orawerpositiondetector3/1
3*1.3Focuscontrolloop3/2
3*1*4 Oiscmotorcontrolloop3/2
3.2MicroprocessorPC3 . 1.769.3203/3
3.2*1 Microprocessorsystem3/3
3^2*2 Drawermotorcontrol3/4
3*3SERVO-2 PCP1.769*3303/4
3.3^1Radialcontrol3/4
3*3.2 Radialcontrolcircuit3/4
3*3*3 Automaticgaincontrol-{AGC-}circuit3/5
3«3r-4Offsetcontrolcircuit.3/5
3.3.5Trackdetectingcircuit3/6
3*4PreamplifierandlaserPCB1*769*100*353/6
3.4.1Lasercontrol3/6
3*4^2 Focusand radialcontrolsignals3/6
3«4*3HFsignalamplifier3/6
3.5DecoderPChl-7o^.3003/6
3* t> • 1 Digitalsignalprocessing 3/7
3»5«2Digitalsine-wavegenerator3/7
3. 5.J HFLand 0-Jdetector3/7
3*oOACTC31.769.23 3 3/7
3.t».l digitalfiltering(oversampling)and0/Aconversion3/7
3*6.2 Leveladjustmentandheadphonesamplifier3/3

mmmm eel/ox B225
*•TESTPOINTStADJUSTMENTSOH E225
4i Testpointson622^4/1
4«-l»lTestpointsonSERVOI PCB1«?69*3104/1
4.1.2TestpointsonSERVO2 PCB1.769.3304/3
4.1.3TestpointsonmicroprocessorPCB1.769*3204/4
4.1.4TestpointsondecoderPCB1.769.3004/6
4.1.5Testpointson0AC-PCB1.769.2604/8
4®2AdjustmentsonCOplayerB2254/9
4.2.1Aids4/9
4.2.2Aligningtheplayermechanism?general4/9
4*2®3 Adjustingthelasercurrent4/9
4.2.4Adjustingthebalance4/9
4«Z*5Adjustingthefocusgain4/10
4*2*6 Checkingthe-tinglealignment4/10
4*»2#7 AdjustingtheDCcomponentofthefocussignal4/11
4.3Measuringtheaudi.odata4/11
4*3.1 A i 4s 4/i1
4*3#2 Harmonicdistortion4/11
4.3.3Outputlevel4/11
4.3*4 Frequencyresponse4/11
4.3.5Crosstalk4/12
4.3.6Signal-to-noiseratio*linear4/12
4.3.7Signal-to-noiseratio?weighted- ' 4/12
4.3.3Phaselinearity4/12
4.4ListeningtestwithreferenceCO4/12
5*DIAGRAMS
6.SPAREPARTS
7* TECHNICALAPPENDIX
7.1Technicaldata7/1
7«Z Dimensions7/2"

R^/ax B225
1.
1.1
GENERAL
IndexofCDplayercontrols
1.1.1 Generalcontrols
1IjPOWER*
[ 2 j LOAD
[ 3 J STOP*
[ 4 J PLAY/NEXT
H5"fREPEAT
[6j(CDdrive)
[7j(Display)
[8j(keys0-9)
KeyforswitchingtheCDplayerONand
OFF. However,certainassemblies(such
astheIRreceiver)remainalwaysswitched"
on(inso-calledstandby mode).
Thedrawerwiththeplayermechanism
[6jopensorcloseswhenthiskeyis
pressed.
Interruptstheplayerfunction.The
opticallaserheadisretractedtothe
startingpositionandtheprogramis
cancellediftheCDplayerwasinprogram
mode. Thepositioninwhichthelaser
pickupwasoperatingbeforeSTOPwas
pressedcannotbereproduced.Ifthis
isdesired,pleaserefertotJL (PAUSE)
key.
Playkeywiththefollowingfunctions;
IfpressedafterLOAD[2j,theCDstarts
torotate,thecontentlistisread,and
thediscisplayedstartingatthefirst
selection (TRACK). Thenextselection
(TRACK)isaccessedwhenthiskeyis
pressedagain.
IfpressedafterPROGRAMMODE[26 J has
beenselected:playprogrammodeis
activated.
Theselectioncurrf.r^lybeingplayed
isrepeatedimmediatelywhenthiskey
ispressed.IftheCDplayerisinSTOP
mode, thefirstselectionofthecompact
discwillbeplayed.IftheCDplayeris
inprogrammode,thecurrentprogramstep
willberepeated.
DrawermodulewithCDplayermechanism
andliquid-crystaldisplay.Thedrawer
canbeopenedorclosedwithLOAD[2].
MultifunctionLCdisplay'whichprovides
informationonalloperatingmodesof
theCDplayerandthecontentofthe
loadedcompactdisc.
Digitkeysfordirectaddressingof
aselection(TRACK)inconjunctionwith
PLAY/NEXT[4j,orforprogramming.
TheCDplayercanbeswitchedonbypressinganyof
thecontrols [ Ijthrough[8joftheupperrow(except
REPEAT[5jandthedigitkey0).TheCDplayerstarts
intheselectedoperatingmode.

mruim REVOX B225
1.1.2 Specialcontrols
Thecontrols inthe lowerfront-panelsection canbe
roughlydividedinto two functiongroups:controls
forsupplementaryplayerfunctions, and programming
controls.
AControls for supplementaryplayerfunctions
[9]PHONES
[10]VOLUME +
[11jVOLUME -
[12] CAL TONE *
13]AUTOSTOP
[14j Key•
[15J VA (pause ) *
[16] « key
[17]DISPLAY
HeadphonesjaGksocket for headphones
200 to600 ohms.
Increases the headphoneslevel
and the level ofthe VARIABLEOUTPUT.
Decreases the headphoneslevel
and the level ofthe VARIABLEOUTPUT
Thiscalibrationbuttonconnects a
1000 Hz calibrationtone tothe
outputs so that the recordinglevel
of a connectedtapedeck canbe
accuratelyadjusted. The1000Hz
CALTONEcorresponds tothe maximum
outputlevel.Thismaximumlevel
issystem-dependent and will not
beexceededeven by shortpeak
pulses.
Interrupts the playingsequence
at theendofthe currentselection
orprogramstep. The laserpickup
isautomaticallypositioned at
thebeginning ofthe nextselection.
Thenextselection is started
immediatelywhenPAUSE TA[15]is
pressed.Uponconclusion of this
selection, theCD playerswitches
again to PAUSEmode.
Repositions the pickupfrom any
locationtoward theend.
Interrupts the playingsequence
at any time.
Repositions the pickupfrom any
locationtoward the start.
Switchesover the displaymode.
Thetimeelapsedsince the start
of the currentselection is displayed
innormalPLAYmode. The total
playtimefrom the start tothe
currentselection canbe displayed
bypressingthis key.
Thesefunctions can also be programmed.
PROGRAMMINGkeys
18]LOOP *
19] +
[20] -
[21] IR SENSOR
[22]STORE
[23]MARK
[24]TRACK/TIME
CommandkeyforrepeatingtheCD
ortheproqr^4«untilSTOP[3jis
pressed.
Forward"paging"inprogrammode.
Particularlyusefulformodifying
anexistingprogram.
Samefunctionas[19]butbackward
paging.
Infraredreceiverwindow
Memoryloadkeytobepressedafter
eachprogramstepentry.Thenext
programstepissubsequently
displayedsothatthecorresponding
entriescanbemade.
Allowsa startanda stopmark
tobesetinprogrammingmodewhile
aselectionisbeingplayed.Any
CDlocationcanthusbeprogrammed.
Switchesthedisplayinprogramming
modefromselection(track)input
totimeinput(minutesand seconds).

mWU\n)MPd R^OX B225
[25jCURSOR
[26J PROGRAM
1.1.3Rear-panelconnectors
[30]AUDIOOUTPUTFIXED.Outputforconnecting
anamplifieronwhichtheinputcanbematched
totheleveloftheCDplayer(theREVOXB251
amplifierisideallymatchedatthe factory).
[31]AUDIOOUTPUTVARIABLE.Activespeakersor
anoutputstagefetc.canbeconnecteddirectly
tothisoutput.Thevolumecanbeadjusted
withVOLUME+ and- onthefrontpanelof
theCDplayer.
[32]ACPOWER.Powerinlet(thesettingofthe
linevoltageselectorcanbecheckedadjacent
toit ) .
..[33J • " REMOTE.Thisconnectorcanbeusedfor:a)
disablingtheIRreceiverandb)connecting
acable-typeremotecontroldevice.
Anypositiononthedisplaycan
beeditedbyapproachingitwiththe
cursor. NOTE;ifthedisplayisin
TIMEmode,thecursormustbe
advancedwiththiskeyinorderto
enterthesecondsaftertheminutes.
Setstheprogramentrymode.If
PLAY/NEXT[4Jispressedafter
theprogramentrieshavebeen
completed,theCDplayerstartsin
PROGRAMmode,
IftheCDplayeristobestarted
innormalmodeaftertheprogram
entrieshavebeencompleted,press
thePROGRAMkey [ 26J againbefore
PLAY/NEXT[4].

B^OX B225 SECTION2/1
2 . REMOVALOFASSEMBLIES
Important:
DisconnecttheCDplayerfromtheACsupplybefore
removinganypartsofthehousing..Forcertainwork
itisnecessarytoopenorclosethedrawermodule.
Thiscanbedonemanuallywithoutdamagingtheunit.
2.1Removingthetopcover
-Unfastenfivescrews[AjontherearoftheCDplayer.
-Withdrawcovertowardtherear.
2.2Removingthesidepanels
-Unfastentwoscrewsoneachsidepanelinorderto
removethem.
2 . 3 Removingtheindividualcircuitboards
Thecircuitboardsareaccessiblewhenthetopcover
isremoved(Section2.1).
Thecircuitboards1.769.280(DACPCB),1.769.300
(DECODERPCB),and1.769.330(SERVO2 PCB)canbepulled
outoftheinterconnectionboardafterthefixingscrews
[B]havebeenunfastened.
FourconnectorsmustbedetachedbeforethePCB1.769.320
(MICROPROCESSOR)isremoved.Thenunfastenscrew[Bj
andwithdrawthePCBfromthehousingtowardtherear.
TheSERVO1 PCB1.769.310isconnectedtothechassis
viathecoolingplateofthevoltageregulators.First
detachallconnectorsleadingtothisPCB.Pushthe
draweroutcompletelyinordertogainaccesstothe
threefixingscrews.Thethreescrews[C]can
subsequentlybeunfastenedandthePCBwithdrawntoward
therear .
2 . 4 Removingtheplayermechanism.
-Removetopcover(Section2.1)
-PushdraweroutpartofthewayandsettheCDplayer
upsidedown.
-Nowpullthedrawerouttothepointwherethescrews
[Dj^becomeaccessible.
-Unfastenscrew[DjandsettheCDplayeragaininits
- . ~ normaloperatingpositiononthe fc--^ch (NOTE;holdthe
playermechanismwithyourhandtopreventitfrom
fallingoutofthe drawer).
-PulldraweroutcompletelyandcarefullylifttheCD
player.

'umrnm ¥%EMOK B225
Detachthesixconnectors(seeFig.2.5).
Theplayermechanismcannowbeliftedoutofthe
drawer»
SECTION2/2
2.5Removingthedisplay
-Openthedrawerandunfastentwoscrews [ Ej oneach
side.
-Unfastencableclamp[F]anddetachconnectorof
cableharness.Thedisplaycannowbeliftedout
bycarefullyslidingthecableharnessoutbelow
theplayermechanism.
2•6Removingthepowertransformer
-Removetopcover(seeSection2.1).
• - JJniiastenfourscrews[Gjfromthebottom.
-Detachtheconnectorsofthepowertransformerto
theSERVO1 PCB1.769.310,removepowerinletby
unfasteningthetwoscrewsandunfastenscrew[Hj
(blackcable,solderingtag).
-Thetransformercannowberemoved.
2.7Removingthedrawermotor
-Removetopcover(seeSection2.1).
-Removepowertransformer(seeSection2.6).
-Unfastenthreescrews[Hjfromthetop,unhookspring
[I], detachconnectorsleadingfromthemotorto
themicroprocessorPCB1.769.320,andcarefullylift
outthemotor.

UJPEMKiKEl/OX • . B226
2.8Removingtheoperatingpanel
-Removetopcover(Section2.1)andsidepanels
(Section2.2).
-Unfastenfourscrews[Kjeachonthetopandthe
bottomoftheoperatingpanel.
Carefullywithdrawoperatingpanel'fromthechassis
anddetachtheconnectors.
2-9Removingtheguiderods
-Removetopcover(seeSection2.1).
-Unfastentheinnerretainingring[Lj;therodcan
nowbepulledoutoftheunitfromtherear.
Note: DonotlosethesmallO-ringthatcushionsthe
drawerstop-
2.10Reassembly
TheCDplayerisreassembledbyfollowingthedismantling
stepsinthereverseorder.Itisabsolutelyessentialto
securethecableharnessinthedrawerwitha clipas
illustratedinFig.2.7.

R^OX B225 SECTION3/1
3.CIRCUITDESCRIPTIONS
3.1SERVO1 PCB 1.769.310
ThefollowingcircuitsareimplementedontheSERVO1
PCB;
-Stabilizationofthesupplyvoltages
-Drawerpositiondetector
-Focuscontrolloop
-Discmotorcontrolloop
3.1.1Stabilizationofthesupplyvoltages
Allsupplyvoltagesarestabilizedbyvoltagecontrollers
(IC4 toIC9, LM317/LM337).
The+5Vsupply(+5V STBY)isalwaysavailable.It
suppliesthemicroprocessorsystemandtheIRreceiver
evenwhentheCDplayerisswitchedoff (standby).
Theremainingsupplyvoltagesareswitchedonoroff
bythemicroprocessorwiththePS-OFFsignal.When
theCDplayerisswitchedoff,PS-OFFbecomes"H"(+5V)
andtransistorsQ9andQ10becomeconductive
(staturated), causingthe+5V and+12V supplyvoltages
todroptoa residualvoltageof1.3V.The-7V supply
isswitchedoffthroughthecircuitR38, R39? andQ8;
the-12V supplyviaR52,R54,andQll;andthe-17V
supplyviaR51, R53f andQ12.Thispreventsthepositive
supplyvoltagesfrombecomingnegative.Thevoltage
isdoubledthroughdiodesD15,D16,D17andcapacitors
C29, C30# andtakentothevoltagecontrollerIC9for
the-17V supply.D18protectsthecontrollerfrom
anexcessivedirect-axiscomponentofthevoltage.
3.1.2Drawerpositiondetector
ThetwolightbarriersDLQ1andDLQ2(onPCB 1.769.310)
checkwhetherthedrawerisopenorclosed.The
correspondingsignalsindicatethefollowingconditions:

R^OX B225 SECTION3/2
3.1.3Focuscontrolloop
Thelenscanbemovedverticallyandisdesignedsimilar
tothemechanicalsystemofa speaker.Thelensis
controlledmagnetically.Thecoilisstationaryand
themagnetmoves.ThefocuserrorsignalFOC-ERRis
firstamplified(leadamplifierIC2a,R3,R12,R16,
R17, C3,C4)andsubsequentlytakentothecontrolling
amplifier ("lag" amplifierRl,R2,R5,Rll,R15,R29,
R30, C2,C12,IC2b,Q6,Q7andtheimpedanceofthe
lens coil). InSTOPmode,thecontrolloopisinterrupted
viaQlbythesignalFOC-0{=H)whichmeansthatno
unnecessarypowerisconsumedbytheoutput-amplifier
(Q6andQl).
Thestart-upcircuit(IC1,R6,R7 ) adjuststhefocussing
tothereflectivelayerofthecompactdisc.Thesignals
FC-1andFC-2arealternatingiyswitchedto"H",causing
thelenstomovealternatingiyupordown.Oncethe
correctfocushasbeenfound,thesignalFOC-NEGbriefly
dropsto"L".Themicroprocessorthenenablesthefocus
controlloop (FOC-0, FC-1,andFC-2- "L" ).. Upto12,000
trackspersecondareskippedinfastsearchmode.
Becausethefocussinglensreadjustsforeachtrack,a
whistlingsoundofapproximately12kHzwoulddevelopas
isthecasewitha speaker.Thiswhistlingsoundis
eliminatedbyR60,R61,C31,Q13inthecontrolloop.
Thisfilterisonlyactiveinsearchmode.
3.1.4Discmotorcontrolloop
Thedatafromthecompactdiscmustbesuppliedas
steadilyaspossibletothedigitalsignalprocessing
circuit. Thespeedwithwhichthesedata(bits)arrive
dependsonthepositionofthelaserpick-up(constant
peripheralspeedbetween1.2and1.4m/s).
Ifthelaserpick-upreadsinthemiddleoftheCD,
the^speedis-muchhigherthanneartheedge.Thespeed
correctionsignalMCESisgeneratedintheerror
correctionIc"(SAA7020onPCB 1.769.300).
ThesignalMCESisswitchedofforonviathesignal
FOC-0(R15,R16,IC3bonPCB 1.769.330). Thesignal
isfirstfilteredviaa 2ndorderlowpass(R22,R23,
R25r R26,R28,C10,Cll, IC3b). The"leadnetwork"
isformedbyC9,R19,R21,R24,andR28,the,rlagnetwork"
byIC3a,C6,C7 , R8 , Q2,andQ3.
Assoonasthefocalpointhasbeenfound,thesignal
FOC-0changesto"LOW1'andthesignalMCESisenabled.
AnegativepulseviaC5issimultaneouslytriggeredon
IC3a, pin3,therebyfullydrivingtransistorQ3inorder
torapidlyacceleratethecompactdisc.Thespeedis
subsequentlycontrolledbytheMCESsignal.