Arcam-Alpha8-cd-sm 电路图 维修手册.pdf

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1、ALPHA 7/8/9 CD SERVICE MANUALALPHA 7/8/9 CD SERVICE MANUAL Arcam Alpha 7/8/9 CD Service Manual Issue 1 Serial No. 0001 - (Paul Newton July 96) Circuit Description The following notes describe the operation of the Alpha 7/8/9 CD players. They include the circuitry on the main, DAC and display PCBs bu

2、t not that on the servo PCB attached to the mechanism. Power Supplies The mains input is fitted with inductors L2,3,6,7 to filter electromagnetic interference coming out of the player. Mains transformer T201 has three secondary windings supplying two separate power supplies and an AC supply for the

3、display filament: Analogue Supply Bridge rectifier D4,5,6,7 and reservoir capacitors C209-C212 produce unregulated split rails of about +/-22V. Z204 and Z205 provide regulated outputs of +18V and -18V respectively that power the opamps in the audio output stage. Since there is no power switch on thi

4、s secondary, the analogue supplies are always connected. Digital Supply Switch SW201-A disconnects the digital secondary winding when the Power switch is out. An unregulated supply of about 11V is produced by the bridge rectifier D8,9,10,11 and reservoir capacitor C36. This is then regulated to prov

5、ide three +5 volt supplies (Z208 general logic supply, Z207 DAC supply, Z203 system clock generator supply) and a +7.3v supply for themechanism and motor drive circuits(Z206). A -30v supply is formed by Z209 and associated components to power the display grid. Muting When the unit is turned off SW20

6、1-A discharges capacitor C29 quickly. This along with the AMUTE signal from the microprocessor, controls the output mute transistors Q1,101 via level shifter Q3. Clock Generator The system clock is generated by a discrete oscillator based around Q2 and 16.9344MHz oscillator X1. The output of Q2 is a

7、mplified and buffered by inverters Z202-E & D and sent to the clock input of the DAC Z201. 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 input to pins 1 to 3. The system clock is input to pin 5. The

8、DAC is powered entirely from one 5V supply, although it is split and decoupled between the analogue and digital sections of the device. The analogue outputs from each channel are processed identically.Three poles of filtering are provided by the active filter based around Z1-A. Z1-B buffers the audi

9、o 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 Arcam Alpha 6 DAC PCB but designed for Sony format input data and a better digital filter, the SM5843AP1, Z14.The digital filter is us

10、ed with a SM5864AP 20-bit DAC chip, Z12, (described here as a PWM noise shaper to avoid confusion with the 1-bit DAC Latch which follows it). The output from this is re-latched by Z7, Z8. Digital FilterA PIC micro on the mother board controls the filter with the signals RB0 to RB7. The SM5843 filter

11、 has internal pull-up resistors on its inputs resulting in RB4 & RB5 being logic 1. The SM5843APT requires several control lines from the 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, Sel

12、ects input word length. Static high for 16 bits. RB4 MDT, Serial data input for volume control. Burst at 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 volume control. RB1 MCK, Serial clock input for volume c

13、ontrol. RB0 Not connected. No Dither On Silence The digital filter adds dither to the output signal. This improves the low-level performance of the DAC. The PWM filter normally mutes when it detects digital silence to prevent any unwanted noise and idle-tones on the audio outputs when no music is pl

14、aying. A slight click is audible when this happens. Unfortunately, the added dither prevents this mute from operating because it holds it open. Q11 detects digital silence on the data input to the filter. When silence is detected, the dither function is switched off RadioFans.CN 收音机爱 好者资料库 ALPHA 7/8

15、/9 CD SERVICE MANUALALPHA 7/8/9 CD SERVICE MANUAL 16.9344MHz Low-Jitter System Clock, X1, Q5 & Z13 SM5843AP1 Digital Filter, Z14 74HC74 Latches, Z7 & Z8 SM5864 PWM Noise Shaper, Z12 Analogue Filter, Z1, Z2, Z3, Z4 Sony Format Digital Audio Control from PIC micro (Z211) on main pcb Audio out Clock Bl

16、ock Diagram of Alpha 8 DAC PCB allowing the PWM filters mute to operate as normal. Mute Relay The mute relay is controlled from the PIC micro via RA0 after switch-on. In Standby mode, XRST is low which interrupts the relay via Q9. RA0 is low when the CD player comes out of standby mode and goes high

17、 after a short settling delay. The power rail, RLYPWR, is un-regulated and has a small reservoir capacitor (on the mother board) so that the relay is released very soon after the mains is disconnected from the CD player before the other power supply rails collapse. PWM noise shaper To reduce EMC, th

18、e clock signal going into this chip, Z12, is very weak on the XTI pin (23) pin, taken directly off Q5. This is amplified so that there should be a larger signal on the CKO pin (26). The PWM output on pins 11, 13, 16 and 18 can be resolved into an audio waveform on a scope simply by measuring them th

19、rough a 100K resistor. The same is true for the PWM signals through the latch and the level shifter. Latch The PWM data from Z12 is re-latched using 74HC74 latches, Z7 and Z8.The power supply for these chips is the DAC voltage reference and the output drives the analogue filter stage directly. The l

20、atches reduce any edge-timing jitter induced on the PWM signal coming from Z12. Analogue filter The first half of the analogue filter, Z3 and Z4 is balanced. The signal through one side of the op-amp, pin 1, should be phase inverted with respect to the other, pin 7. These signals should be viewed on

21、 a scope through a 100K resistor since there may still be quite a lot of RF noise on the signal. Z1 and Z2 filter the audio signal further and also convert the balanced signal into a single ended signal. Z18 acts as a DC servo to reduce the output offset voltage. This has a very large time constant

22、so an offset as high as 50mV is possible when the unit is first plugged in. This reduces to less than 3mV after 10 minutes and stays low if the unit is switched off 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 MANUAL Test Points Marked o

23、n Circuit Diagram Only Test PointsMeasurement Information 17MHzClock 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 dat

24、a 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, s

25、ee 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 when output is un-muted. N15Regulated analogue supply. -15V d.c. +/- 0.6V. N18V-18.45V d.c. +/- 0.5V supply input on SK204 for analogue. P5

26、V(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)+18.4

27、5V 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.

28、 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, see specifications. 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

29、 square wave at 16.9344MHz. RadioFans.CN 收音机爱 好者资料库 ALPHA 7/8/9 CD SERVICE MANUALALPHA 7/8/9 CD SERVICE MANUAL Disc Transport Module The CDM 14 module comprises the disc loading mechanism, laser assembly, RF amplifier and analogue signal processing. All the servo control and motor drive circuits are

30、 also included. Digital Signal Processor Mute, attenuation and de-emphasis functions are controlled via a three-wire serial bus from the system controller (Z212) to pins 26, 27 & 28 of the DAC (Z201). Digital audio is input to the DAC on pins 1, 2& 3 in standard Sony format i.e. Word Clock, Data and

31、 Bit Clock. A digital output complying to the SPDIF standard is generated by the decoder on the mechanisim assembly. This is passed through an isolating transformer, T202, to the digital output socket SK5. System Controller The CXP826P16Q system controller (Z212) is a combined CD player controller,

32、keyboard scanner, remote control decoder and fluorescent display driver. Its clock is generated by 4.00MHz resonator X201. The controller detects the position of the disc drawer from the status of two microswitches, INSW & OUTSW, on socket SK205. The drawer motor is controlled via motor driver Z210

33、The keyboard scanning works by connecting the keys to a resistor ladder on an ADC (analogue to digital convertor) input to the microcontroller. Pressing a key presents a unique voltage to this input. The signal from the remote control receiver is input to RMIN (pin 2) after first passing through the

34、 PIC microcontroller, Z211, on the small remote receiver pcb. This PIC ic converts the RC-5 format codes from the remote control handsets to NEC data, suitable for the Sony chipset. It also controls theconfiguration of the digital filter/DAC on the Alpha 8 and 9 DAC boards the The remote control dat

35、a contains a customer code that identifies it as an Arcam product.The microcontroller is confiqured to accept this code by means of the diode network D291 to D297. Disassembly For Servicing To remove the boards within the CD players follow the instructions below. 1.Remove the top cover. 2.Press load

36、 to eject the CD tray. 3.Unplug the unit from the mains. 4.Push the tray front upwards to remove it from the tray. Push the tray in manually. 5.Remove the 4 screws holding the front panel to the chassis and release the locating tabs. 6.Unplug the flexfoil from the display board where it enters the m

37、ain pcb. 7.Remove the 2 screws holding the remote receiver pcb in place. 8.The front panel can now be pulled off the unit. 9.To remove the display pcb remove the 6 screws holding the board in place. To remove the main pcb first remove the DAC board if it is an Alpha 8 or 9 CD player. 1.Remove the 3

38、screws holding the audio output sockets to the rear panel and 2 screws holding the aluminium extrusion in place. 2.Squeeze the tops of the 2 pcb pillars and lift the board up slightly to clear them . 3.Remove the 2 flexfoils from the DAC board. The DAC board, still attached to the extrusion, can now

39、 be removed from the unit. To remove the main pcb remove the 8 pcb securing screws and the screw holding the digital ouput socket to the chassis. (On Alpha 7 CDs also remove the 3 screws securing the audio ouput sockets in place). Release the cables which connect the mechanism to the main board. The

40、 main pcb can now be slid out of the case. ALPHA 7/8/9 CD SERVICE MANUALALPHA 7/8/9 CD SERVICE MANUAL Alpha 7/8/9 Main PCB Parts List Ref. No.DescriptionPart No. C2PPRO 680P 63V 5% RA2D168 C3PPRO 680P 63V 5% RA2D168 C4ELST NON POLAR 10UF 35V2U610 C5PPRO 100P 63V 5% RA2D110N C6PPRO 680P 63V 5% RA2D16

41、8 C7PPRO 680P 63V 5% RA2D168 C10CERD 1N0 63V2A210 C11CERD 10N 100V 20%2A310 C12CERD 10N 100V 20%2A310 C13CERD 33P 63V2A033 C14CERD 33P 63V2A033 C15CERD 100P 63V2A110 C16CERD 100P 63V2A110 C17CERD 10N 100V 20%2A310 C18CERD 10N 100V 20%2A310 C19CERD 10N 100V 20%2A310 C20PPRO 680P 63V 5% RA2D168 C21ELS

42、T NON POLAR 10UF 35V2U610 C22ELST 100U 25V2N710 C23ELST 100U 25V2N710 C24ELST 100U 25V2N710 C25ELST 22U 20V OSCON2P622 C26ELST 100U 25V2N710 C27ELST 10U 50V2N610 C28CERD 470P 63V2A147 C29ELST 100U 25V2N710 C32CERD 10N 100V 20%2A310 C33ELST 1M0 25V2N810 C34ELST 100U 100V2N710B C35ELST 100U 100V2N710B

43、 C36ELST 3M3 25V2N833 C37ELST 10U 50V2N610 C38ELST 10U 50V2N610 C39ELST 100U 25V2N710 C40ELST 100U 25V2N710 C41ELST 100U 25V2N710 C42ELST 100U 25V2N710 C43ELST 1M0 25V2N810 C44ELST 1M0 25V2N810 C45ELST 1M0 25V2N810 C46ELST NON POLAR 10UF 35V2U610 C47ELST 1M0 25V2N810 C48ELST 1M0 25V2N810 Alpha 7/8/9

44、 Main PCB Parts List Ref. No.DescriptionPart No. C49ELST 10U 50V2N610 C50ELST 10U 50V2N610 C51ELST 1M0 25V2N810 C52CERD 10N 100V 20%2A310 C53ELST 22U 20V OSCON2P622 C54CERD 10N 100V 20%2A310 C55CERD 10N 100V 20%2A310 C56ELST 10U 50V2N610 C102PPRO 680P 63V 5% RA2D168 C103PPRO 680P 63V 5% RA2D168 C104

45、ELST NON POLAR 10UF 35V2U610 C105PPRO 100P 63V 5% RA2D110N C291CERD 47N 63V 10%2A347 C292ELST 100U 25V2N710 C293CERD 47N 63V 10%2A347 C294CERD 47N 63V 10%2A347 D1SSDIODE 1N4148 75V3A4148 D2SSDIODE 1N4148 75V3A4148 D3SSDIODE 1N4148 75V3A4148 D4RECTIFIER 1N4003F 1A 200V3B4003 D5RECTIFIER 1N4003F 1A 20

46、0V3B4003 D6RECTIFIER 1N4003F 1A 200V3B4003 D7RECTIFIER 1N4003F 1A 200V3B4003 D8RECTIFIER 1N4003F 1A 200V3B4003 D9RECTIFIER 1N4003F 1A 200V3B4003 D10RECTIFIER 1N4003F 1A 200V3B4003 D11RECTIFIER 1N4003F 1A 200V3B4003 D12RECTIFIER 1N4003F 1A 200V3B4003 D13RECTIFIER 1N4003F 1A 200V3B4003 D14RECTIFIER 1N

47、4003F 1A 200V3B4003 D15RECTIFIER 1N4003F 1A 200V3B4003 D16RECTIFIER 1N4003F 1A 200V3B4003 D17ZENER 15V 400MW3C11504 D18ZENER 7V5 400MW3C07504 D19ZENER 4V7 400MW3C04704 D20ZENER 4V7 400MW3C04704 D21SSDIODE 1N4148 75V3A4148 D22RECTIFIER 1N4003F 1A 200V3B4003 D23RECTIFIER 1N4003F 1A 200V3B4003 D291SSDI

48、ODE 1N4148 75V3A4148 D292SSDIODE 1N4148 75V3A4148 D293SSDIODE 1N4148 75V3A4148 D294SSDIODE 1N4148 75V3A4148 ALPHA 7/8/9 CD SERVICE MANUALALPHA 7/8/9 CD SERVICE MANUAL D295SSDIODE 1N4148 75V3A4148 D296SSDIODE 1N4148 75V3A4148 D297SSDIODE 1N4148 75V3A4148 DISP301DISPLAY ALPHA 7/8/9 (SONY)B1008 F1INS C

49、OVER PCB FUSEHOLDERF022 F1FUSE 20mm 160mA TC11166 F1/ FUSEHOLDER 20mm PCB8S004 F2/ FUSEHOLDER 20mm PCB8S004 F2INS COVER PCB FUSEHOLDERF022 F4FUSE 20mm 160mA TC11166 F4SPARE FUSEHOLDERF062 HS1HEATSINK TO220 CLIP 30F007 HS2HEATSINK TO220 8.6 DEGC/WF008 HS2HEATSINK CLIP TO220 13/8.6 DC/WF006 L1FERRITE BEAD SINGLE AXIAL TAPED 2K BOX7F003 L2INDUCT 1R0 283AS-1R0K 34-109147D001 L3INDUCT 1R0 283AS-1R0K 34-109147D001 L433UH IND 34-483307D033 L533UH IND 34-483307D033 L66U8H INDUCTOR7D968A L76U8H INDUCTOR7D968A LED201LED RED 5MM3D5119 LED301LED GREEN 5MM3D001 LK101AJUMPER 4-WAY LEADL814CA PAD