Arcam-Alpha8-cd-sm维修电路原理图.pdf

ALPHA 7/8/9 CD SERVICE MANUALALPHA 7/8/9 CD SERVICE MANUALArcam Alpha 7/8/9 CD Service ManualIssue 1 Serial No. 0001 - (Paul Newton July 96)Circuit DescriptionThe following notes describe the operation of theAlpha 7/8/9 CD players. They include the circuitry onthe main, DAC and display PCBs but not that on theservo PCB attached to the mechanism.Power SuppliesThe mains input is fitted with inductors L2,3,6,7 tofilter electromagnetic interference coming out of theplayer.Mains transformer T201 has three secondarywindings supplying two separate power supplies andan AC supply for the display filament:Analogue SupplyBridge rectifier D4,5,6,7 and reservoir capacitorsC209-C212 produce unregulated split rails of about+/-22V.Z204 and Z205 provide regulated outputs of +18Vand -18V respectively that power the opamps in theaudio output stage. Since there is no power switch on this secondary, theanalogue supplies are always connected.Digital SupplySwitch SW201-A disconnects the digital secondarywinding when the Power switch is out.An unregulated supply of about 11V is produced bythe bridge rectifier D8,9,10,11 and reservoircapacitor C36.This is then regulated to provide three +5 voltsupplies (Z208 general logic supply, Z207 DACsupply, Z203 system clock generator supply) and a+7.3v supply for themechanism and motor drivecircuits(Z206).A -30v supply is formed by Z209 and associatedcomponents to power the display grid.MutingWhen the unit is turned off SW201-A dischargescapacitor C29 quickly. This along with the AMUTEsignal from the microprocessor, controls the outputmute transistors Q1,101 via level shifter Q3.Clock GeneratorThe system clock is generated by a discrete oscillatorbased around Q2 and 16.9344MHz oscillator X1. Theoutput of Q2 is amplified and buffered by invertersZ202-E & D and sent to the clock input of the DACZ201. DAC & Audio Outputs (Alpha 7 only)The DAC is a Delta-Sigma design from Burr Brown,the PCM1710U.The serial digital data from the decoder Z206 is inputto pins 1 to 3. The system clock is input to pin 5. The DAC is powered entirely from one 5V supply,although it is split and decoupled between theanalogue and digital sections of the device.The analogue outputs from each channel areprocessed identically.Three poles of filtering areprovided by the active filter based around Z1-A. Z1-Bbuffers the audio output and sets the output level.Muting is provided by turning on Q1 and Q101.DAC & Audio Outputs (Alpha 8 only)This is a similar circuit as the one used on the ArcamAlpha 6 DAC PCB but designed for Sony formatinput data and a better digital filter, the SM5843AP1,Z14.The digital filter is used with a SM5864AP 20-bitDAC chip, Z12, (described here as a PWM noiseshaper to avoid confusion with the 1-bit DAC Latchwhich follows it). The output from this is re-latched byZ7, Z8.Digital FilterA PIC micro on the mother boardcontrols the filter with the signals RB0 to RB7. TheSM5843 filter has internal pull-up resistors on itsinputs resulting in RB4 & RB5 being logic 1.The SM5843APT requires several control lines fromthe PIC.RB7 FSEL2, Selects sampling rate for de-emphasis.Static low for 44.1K.RB6 FSEL1, Selects sampling rate for de-emphasis.Static low for 44.1K.RB5 IW2N, Selects input word length. Static high for16 bits.RB4 MDT, Serial data input for volume control. Burstat switch-on for setting to full.RB3 RSTN, Reset line. Short pulse low at switch on,then static high.RB2 MLEN, Serial data latch input for volumecontrol.RB1 MCK, Serial clock input for volume control.RB0 Not connected.No Dither On SilenceThe digital filter adds dither to the output signal.This improves the low-level performance of the DAC.The PWM filter normally mutes when it detectsdigital silence to prevent any unwanted noise andidle-tones on the audio outputs when no music isplaying. A slight click is audible when this happens.Unfortunately, the added dither prevents this mutefrom operating because it holds it open. Q11 detectsdigital silence on the data input to the filter. Whensilence is detected, the dither function is switched offRadioFans.CN 收音机爱 好者资料库ALPHA 7/8/9 CD SERVICE MANUALALPHA 7/8/9 CD SERVICE MANUAL16.9344MHz Low-Jitter System Clock, X1, Q5 & Z13SM5843AP1 Digital Filter, Z1474HC74 Latches, Z7 & Z8SM5864 PWM Noise Shaper, Z12Analogue Filter, Z1, Z2, Z3, Z4Sony Format Digital AudioControl from PIC micro (Z211) on main pcbAudio outClockBlock Diagram of Alpha 8 DAC PCBallowing the PWM filters mute to operate as normal.Mute RelayThe mute relay is controlled from the PIC micro viaRA0 after switch-on. In Standby mode, XRST is lowwhich interrupts the relay via Q9. RA0 is low whenthe CD player comes out of standby mode and goeshigh after a short settling delay.The power rail, RLYPWR, is un-regulated and has asmall reservoir capacitor (on the mother board) sothat the relay is released very soon after the mains isdisconnected from the CD player before the otherpower supply rails collapse.PWM noise shaperTo reduce EMC, the clock signal going into this chip,Z12, is very weak on the XTI pin (23) pin, takendirectly off Q5. This is amplified so that there shouldbe a larger signal on the CKO pin (26).The PWM output on pins 11, 13, 16 and 18 can beresolved into an audio waveform on a scope simplyby measuring them through a 100K resistor. Thesame is true for the PWM signals through the latchand the level shifter.LatchThe PWM data from Z12 is re-latched using 74HC74latches, Z7 and Z8.The power supply for these chipsis the DAC voltage reference and the output drivesthe analogue filter stage directly. The latches reduceany edge-timing jitter induced on the PWM signal coming from Z12.Analogue filterThe first half of the analogue filter, Z3 and Z4 isbalanced. The signal through one side of the op-amp,pin 1, should be phase inverted with respect to theother, pin 7. These signals should be viewed on ascope through a 100K resistor since there may stillbe quite a lot of RF noise on the signal.Z1 and Z2 filter the audio signal further and alsoconvert the balanced signal into a single endedsignal. Z18 acts as a DC servo to reduce the outputoffset voltage. This has a very large time constant soan offset as high as 50mV is possible when the unitis first plugged in. This reduces to less than 3mVafter 10 minutes and stays low if the unit is switchedoff and on with the Standby button.RadioFans.CN 收音机爱 好者资料库ALPHA 7/8/9 CD SERVICE MANUALALPHA 7/8/9 CD SERVICE MANUALTest Points Marked on Circuit Diagram OnlyTest PointsMeasurement Information17MHzClock Output to mother board. 16.9344MHz +/- 40ppm, 4V to 5V peak to peak square wave.AGNDAnalogue ground point.AMUTEDigital audio mute input on SK203. 0V=off, 5V=Mute.CKSerial Data clock input on SK203. Sony format.DASerial Data data input on SK203. Sony format.CLKSYNCCrystal clock override. A 16.9344MHz HCMOS clock can be injected from an external source.DEEMDe-emphasis select input on SK203. 0V=off, 5V=On.DGNDDigital ground point.LOUTLeft channel audio output at SK1. Measure d.c. offset at switch-on and after 1 minute, see specifications.LRSerial Data LR input on SK203. Sony format.MUTERLYMute Relay Voltage. Equal to RLYPWR voltage when output is muted and 0V d.c. +0.5V,-0.0V whenoutput is un-muted.N15Regulated analogue supply. -15V d.c. +/- 0.6V.N18V-18.45V d.c. +/- 0.5V supply input on SK204 for analogue.P5V(0)+5V d.c. +/- 0.3V digital filter supply input on SK204. P5V(1)+5V d.c. +/- 0.3V PWM noise shaper supply input on SK204.P5VCLKRegulated clock supply. +5V d.c. +/- 0.3V.P15Regulated analogue supply. +15V d.c. +/- 0.6V.P18V(0)+18.45V d.c. +/- 0.5V supply input on SK204 for analogue.P18V(1)+18.45V d.c. +/- 0.5V supply input on SK204 for clock and latch.PWRGNDPower ground point. Used by mute relay only.RA0Mute relay control from PIC micro on SK203.RB0-RB7Control lines from PIC micro on SK203.REFLDAC reference voltage, left channel. +5V +/- 0.3V.REFRDAC reference voltage, right channel.RLYPWR+12V d.c. +/- 1V supply input for mute relay on SK204.ROUTRight channel audio output at SK1. Measure d.c. offset at switch-on and after 1 minute, seespecifications.SRVLLeft d.c. servo voltage. -10 to +10V d.c.SRVRRight d.c. servo voltage.SYSCLKClock used by latches. 4V to 5V peak to peak square wave at 16.9344MHz.ALPHA 7/8/9 CD SERVICE MANUALALPHA 7/8/9 CD SERVICE MANUALDisc Transport ModuleThe CDM 14 module comprises the disc loadingmechanism, laser assembly, RF amplifier andanalogue signal processing. All the servo control andmotor drive circuits are also included.Digital Signal ProcessorMute, attenuation and de-emphasis functions arecontrolled via a three-wire serial bus from the systemcontroller (Z212) to pins 26, 27 & 28 of the DAC(Z201).Digital audio is input to the DAC on pins 1, 2& 3 instandard Sony format i.e. Word Clock, Data and BitClock.A digital output complying to the SPDIF standard isgenerated by the decoder on the mechanisimassembly. This is passed through an isolatingtransformer, T202, to the digital output socket SK5.System ControllerThe CXP826P16Q system controller (Z212) is acombined CD player controller, keyboard scanner,remote control decoder and fluorescent displaydriver. Its clock is generated by 4.00MHz resonatorX201.The controller detects the position of the disc drawerfrom the status of two microswitches, INSW &OUTSW, on socket SK205. The drawer motor iscontrolled via motor driver Z210The keyboard scanning works by connecting the keysto a resistor ladder on an ADC (analogue to digitalconvertor) input to the microcontroller. Pressing akey presents a unique voltage to this input.The signal from the remote control receiver is inputto RMIN (pin 2) after first passing through the PICmicrocontroller, Z211, on the small remote receiverpcb. This PIC ic converts the RC-5 format codesfrom the remote control handsets to NEC data,suitable for the Sony chipset. It also controlstheconfiguration of the digital filter/DAC on the Alpha8 and 9 DAC boards the The remote control datacontains a customer code that identifies it as anArcam product.The microcontroller is confiqured toaccept this code by means of the diode networkD291 to D297.Disassembly For ServicingTo remove the boards within the CD players followthe instructions below.1.Remove the top cover.2.Press load to eject the CD tray.3.Unplug the unit from the mains.4.Push the tray front upwards to remove itfrom the tray. Push the tray in manually.5.Remove the 4 screws holding the front panelto the chassis and release the locating tabs.6.Unplug the flexfoil from the display boardwhere it enters the main pcb.7.Remove the 2 screws holding the remotereceiver pcb in place.8.The front panel can now be pulled off theunit.9.To remove the display pcb remove the 6screws holding the board in place.To remove the main pcb first remove the DAC boardif it is an Alpha 8 or 9 CD player.1.Remove the 3 screws holding the audiooutput sockets to the rear panel and 2screws holding the aluminium extrusion inplace.2.Squeeze the tops of the 2 pcb pillars and liftthe board up slightly to clear them .3.Remove the 2 flexfoils from the DAC board.The DAC board, still attached to the extrusion, cannow be removed from the unit.To remove the main pcb remove the 8 pcb securingscrews and the screw holding the digital ouput socketto the chassis. (On Alpha 7 CDs also remove the 3screws securing the audio ouput sockets in place).Release the cables which connect the mechanism tothe main board.The main pcb can now be slid out of the case.ALPHA 7/8/9 CD SERVICE MANUALALPHA 7/8/9 CD SERVICE MANUALAlpha 7/8/9 Main PCB Parts ListRef. No.DescriptionPart No.C2PPRO 680P 63V 5% RA2D168C3PPRO 680P 63V 5% RA2D168C4ELST NON POLAR 10UF 35V2U610C5PPRO 100P 63V 5% RA2D110NC6PPRO 680P 63V 5% RA2D168C7PPRO 680P 63V 5% RA2D168C10CERD 1N0 63V2A210C11CERD 10N 100V 20%2A310C12CERD 10N 100V 20%2A310C13CERD 33P 63V2A033C14CERD 33P 63V2A033C15CERD 100P 63V2A110C16CERD 100P 63V2A110C17CERD 10N 100V 20%2A310C18CERD 10N 100V 20%2A310C19CERD 10N 100V 20%2A310C20PPRO 680P 63V 5% RA2D168C21ELST NON POLAR 10UF 35V2U610C22ELST 100U 25V2N710C23ELST 100U 25V2N710C24ELST 100U 25V2N710C25ELST 22U 20V OSCON2P622C26ELST 100U 25V2N710C27ELST 10U 50V2N610C28CERD 470P 63V2A147C29ELST 100U 25V2N710C32CERD 10N 100V 20%2A310C33ELST 1M0 25V2N810C34ELST 100U 100V2N710BC35ELST 100U 100V2N710BC36ELST 3M3 25V2N833C37ELST 10U 50V2N610C38ELST 10U 50V2N610C39ELST 100U 25V2N710C40ELST 100U 25V2N710C41ELST 100U 25V2N710C42ELST 100U 25V2N710C43ELST 1M0 25V2N810C44ELST 1M0 25V2N810C45ELST 1M0 25V2N810C46ELST NON POLAR 10UF 35V2U610C47ELST 1M0 25V2N810C48ELST 1M0 25V2N810Alpha 7/8/9 Main PCB Parts ListRef. No.DescriptionPart No.C49ELST 10U 50V2N610C50ELST 10U 50V2N610C51ELST 1M0 25V2N810C52CERD 10N 100V 20%2A310C53ELST 22U 20V OSCON2P622C54CERD 10N 100V 20%2A310C55CERD 10N 100V 20%2A310C56ELST 10U 50V2N610C102PPRO 680P 63V 5% RA2D168C103PPRO 680P 63V 5% RA2D168C104ELST NON POLAR 10UF 35V2U610C105PPRO 100P 63V 5% RA2D110NC291CERD 47N 63V 10%2A347C292ELST 100U 25V2N710C293CERD 47N 63V 10%2A347C294CERD 47N 63V 10%2A347D1SSDIODE 1N4148 75V3A4148D2SSDIODE 1N4148 75V3A4148D3SSDIODE 1N4148 75V3A4148D4RECTIFIER 1N4003F 1A 200V3B4003D5RECTIFIER 1N4003F 1A 200V3B4003D6RECTIFIER 1N4003F 1A 200V3B4003D7RECTIFIER 1N4003F 1A 200V3B4003D8RECTIFIER 1N4003F 1A 200V3B4003D9RECTIFIER 1N4003F 1A 200V3B4003D10RECTIFIER 1N4003F 1A 200V3B4003D11RECTIFIER 1N4003F 1A 200V3B4003D12RECTIFIER 1N4003F 1A 200V3B4003D13RECTIFIER 1N4003F 1A 200V3B4003D14RECTIFIER 1N4003F 1A 200V3B4003D15RECTIFIER 1N4003F 1A 200V3B4003D16RECTIFIER 1N4003F 1A 200V3B4003D17ZENER 15V 400MW3C11504D18ZENER 7V5 400MW3C07504D19ZENER 4V7 400MW3C04704D20ZENER 4V7 400MW3C04704D21SSDIODE 1N4148 75V3A4148D22RECTIFIER 1N4003F 1A 200V3B4003D23RECTIFIER 1N4003F 1A 200V3B4003D291SSDIODE 1N4148 75V3A4148D292SSDIODE 1N4148 75V3A4148D293SSDIODE 1N4148 75V3A4148D294SSDIODE 1N4148 75V3A4148ALPHA 7/8/9 CD SERVICE MANUALALPHA 7/8/9 CD SERVICE MANUALD295SSDIODE 1N4148 75V3A4148D296SSDIODE 1N4148 75V3A4148D297SSDIODE 1N4148 75V3A4148DISP301DISPLAY ALPHA 7/8/9 (SONY)B1008F1INS COVER PCB FUSEHOLDERF022F1FUSE 20mm 160mA TC11166F1/ FUSEHOLDER 20mm PCB8S004F2/ FUSEHOLDER 20mm PCB8S004F2INS COVER PCB FUSEHOLDERF022F4FUSE 20mm 160mA TC11166F4SPARE FUSEHOLDERF062HS1HEATSINK TO220 CLIP 30F007HS2HEATSINK TO220 8.6 DEGC/WF008HS2HEATSINK CLIP TO220 13/8.6 DC/WF006L1FERRITE BEAD SINGLE AXIAL TAPED 2K BOX7F003L2INDUCT 1R0 283AS-1R0K 34-109147D001L3INDUCT 1R0 283AS-1R0K 34-109147D001L433UH IND 34-483307D033L533UH IND 34-483307D033L66U8H INDUCTOR7D968AL76U8H INDUCTOR7D968ALED201LED RED 5MM3D5119LED301LED GREEN 5MM3D001LK101AJUMPER 4-WAY LEADL814CAPAD1Alpha 7/8/9 CD SUPPORT PADE805APPL116 WAY DIL PIN HEADER8K6316Q1TRANS LF SS N BC547B4A547Q2TRANS LF SS N BC547B4A547Q3TRANS LF SS P BC557B4A557Q4TRANS LF SS N BC547B4A547Q5TRANS LF SS N BC547B4A547Q6TRANS LF SS N BC547B4A547Q101TRANS LF SS N BC547B4A547R2RES MF W4 3K9 1%1H239R3RES MF W4 3K9 1%1H239R4RES MF W4 3K9 1%1H239R5RES MF W4 1% 10K1H310R6RES MF W4 1% 10K1H310R7RES MF W4 1% 33K1H333R8RES MF W4 3K9 1%1H239R9RE