Arcam P85-3, P85, A85 Service Manual

Service Manual

DiVA A85, P85 & P85/3 Ampliﬁ ers

A85

Issue 2.0

ARCAM

Contents List

Contents list

Circuit description

Service guide

Circuit diagrams

Component overlays

Circuit board parts list

General assembly parts list

Pre-amplifier circuit description

The A85 preampli fier is a high-performanc e, DC coupled design with microproc essor control of in put select, two in dependent tap e loops, electronic volume control, tone bypass and electronic tone control.

It features a discrete power supply and low-noise linear circuitry to obtain very good distortion and noise performance, suitable for high quality sourc e m aterial such as CD or DVD-A.

Input switching

Each of the inputs has a pair of diodes to the ±15V rails to prevent static spikes from causing damage t o the CMOS multip lexers. In addition, there is a simple resistor-capacitor filter with a corner frequency of approximately 340kHz to remove any unwanted high frequency interference from the signal. This uses high-quality polypropylene capacitors for best performance.

Z104 and Z105 are the main input select multipl exers, which are configured in a ‘virtual earth’ unity gain arrangement with Z115 and Z116. This arrangement is slightly lower distortion than the ‘normal’ one, at th e cost of a slightly higher nois e floor. It is an inverting configuration, which is restored to correct polarity by the inverting elect r onic volume control which follows.

Z115B and Z116B are integrating servos, which take out any DC from the input signal before the following stages. The servos are 2pole, with a passive 2 the left channel) to remove broadband noise from the output of the servo and improve speed of response.

Z100 thru Z103 are the input selectors for t he 2 tape loops . These are normal non-inverting selectors which are buffered before being passed on to the phono sockets.

Z109A output is decoupled by R108 which is included in the feedback path . Local h igh freq u ency feed ba ck occu rs aroun d C108 to allow the tape loop output to be very low impedance, whilst being stable into a capacitive load such as may be presented by a screened in terconnect cable. This is the same for all tape outputs.

Z106 is configured as a double pole changeover switch, used to select the tone controls. The tone controls are bypassed when not required so that the noise and distortion can be minimised.

Tone control circuit

The tone control circuit is a non-inverting one, using a gyrated ‘bell’ filter f o r the bass and a simple shelving filter for the t r eble.

Left channel description

The input is attenuated by 6dB and biased to a volt age of +2.5V DC by C111, R113, R112, R110, R111 and C110 . This is so the signals fall within the 0 - 5VDC required by the digital potentiometer Z108.

Z111B and its associated components form an active equivalent of a series resonan t LCR circui t. This has a n impedance m inimum of

5.4k at around 80Hz with Q=0.7 The reason the bass is done as a band-boost filter rather than a shelving filter is so that you can boost the ‘real’ b as s wit hout c ausi ng lot s of s u b- aud i o lou dsp eak er cone excursion which wastes power and may damage the drive units.

pole being formed by R180 and C147 (for

The digital pots Z108D and Z108A control the bass and treble respectively. Th is is done by moving the wiper conn ected to the frequency-sensitive impedance between the non-inverting and inverting terminals of Z112A, effectively changing the ratio of feedback boost and feed-forward attenuation of the circuit at the desired frequencies, thus providing a EQ gain control that is symmetrical on a logarithmic scale, with the use of a linear pot.

Z112B provides the 6dB of gain necessary to bring the nominal signal level back to unity. C116 and C117 remove the 2.5VDC offset from th e output, to preven t clunks when th e tone controls are activated.

Z108 is controlled by a simple 3-wire serial interface from the microprocessor. Each of th e digit al lin es has it s own groun d return to minimise electromagnetic interference. They are connected together only at the GND pin of the IC.

Volume control

Z107 is a VSDVC electronic volume control IC. It works, in conjunction with an external op-amp , by varying t he feed-for ward and feedback resi stors in an inverting gai n configuration. In th is way, it can allow output signal swings of up to 22Vpp whilst operating from a sin gle +5VDC power supply. Also, it allows th e user the choice of external ci rcuitry to fine-tune the p erformance. The gain is controlled from th e microprocessor via a 3 -wire serial interface. The analogue supply rail is derived from the local +5V via R185 and C156 // C157.

Z117 is the output op-amp. Its outputs a re decoupled via R186, R187, C158 and C159 so that it has a low output impedance but can drive cable capacitance without oscillation. R186 and R187 are included in the audio frequency feedback loop to reduce output impedance when driving ‘difficult’ cables.

RLY100 is a mute relay which shunts the preamp output to ground. This is to prevent thumps and squeals when the units is powered up or down.

Power supply

The transformer winding is connected to SK300. The voltage is rectified and smoothed by D300, D301, D306, D307 and C300, C310. The un regulated voltage sh ould be around ±27VDC. F300 and F301 are secondary fuses, as the low power preamp winding would not blow the primary fuses if short circuited.

The voltage regulators a re discrete compound emi tter followers. I will describe the +15V supply as the negative is essentially an exact mirror image.

Q300 and R300 act as a constant current source, supplying around 7mA into D310. C302 and C314 reduce ripple and broadband noise on the zen er diode. Q3 05 and Q306 form a complementary Darlington NPN transistor which is configured as an emitter follower, produ cing the + 15VDC at its output. C303 is to pr ovide bulk charge stora ge an d t o reduce t he AC out put impedanc e of th e power supply. D302 prevents reverse bias of the supply during power down.

Z301 is a conventional LM317 type circuit to drop the +15V rail down to +5V for the tone and volume control circuits.

Star point SP300 explicitly connects the differently named ground nets together at one point, to minimise hum.

Amplifier & PSU Circuit Description

L882PB is the printed circuit board that provides the power supply and output stage amplifiers for the A85 integrated and power amplifiers. Its function is to:

1. Drive the loudspeakers(!)

2. Provide an (always on) auxiliary 5VDC supply for the micro controller and display interface

3. Receive logic signals from the micro controller to turn on the main amp lifier supply rela y (mains) and connect either pair of speaker output sockets

4. Send logic signals to the micro controller pertaining to the state of the amplifiers (short circuit protection, DC offset protection, t hermal protection)

5. Receive and demodulate RC5 remote style control codes via the rear pan el jack and trans mit them to the micr o controller

6. Send a 12V trigger ou tput via the rea r pan el jack for con trol of an auxiliary power amp when the unit is on

7. Receive a 12V trigger input from the rear jack (for u s e in the power amp only version)

8. Drive a pair of headphones via attenuating resistor networks

The power amplifier is a symmetrical, class B, bipolar junction transistor output, current-feedback design (of which more later) with DC-coupled signal and feedback paths, featuring an active integrating volta ge servo to control DC offsets.

It features ‘instantaneous’ safe operating area protection in addition to sending a signal to the micro to turn off the output relays in the even t of user or thermal ove rload. Since it i s a DCcoupled desi gn, the unit senses DC at the output and triggers the micro to turn of f the loudspeak er relays in the even t of excessive levels (possibly due to a faulty source component or short circuit output transistor).

The output s tage uses Sank en specia lised ‘audio a mplifier’ pow er bipolar Darlington transistors which are optimised for use with this type of topology. Consequently the unit has excellent measured performance in terms of noise, slew rate, output impedance and distortion (harmonic and intermodulated) and is essentially load invariant (to a first order th e measu red p erforman ce i s ind epend ent of the load impedance).

L882 Circuit Sheet 1

The audio input to the amplifier is connected to SK102 (which connects to the output of the preamp PCB). This signal is passed on via SK104A which forms the preamp out connection to the outside world.

SK104B provides the power amp input connection, with switch SW100 selecting between pre / power and integrated modes. The unit is wired as a preamp / power amp combination with the switch depressed, allowing the user to insert a processor or other function (e.g. graph ic EQ) between th e output of th e preamp and th e input of the power amp. With the switch in the ‘out’ position the power amp input socket is ignored and the input to the power amp is connected internally to the output of the preamp. PL100 and PL101 are ‘handbag’ links fitted to the power amp only version to connect both pairs of phono sockets in parallel for daisy chaining (as there is no preamp output on a power amp).

Relays RLY100 and RLY101 switch the two pairs of loudspeaker output sockets and are controlled by the micro lines describes above. Transistors TR100 and TR101 operate in ‘constant current sink’ mode which allow relay current to be approximately constant although the main power supply rails will vary with mains input and load conditions. The current is around 20mA per relay.

Star point SP100 is the ground ‘mecca’ for the entire amplifier (comprising a ll three PCBs wit hin the unit ). All of the sepa rately named grounds are joined explicitly at this point. Different named grounds are used to ensure that no two ‘different’ grounds share copper, which could compromise the noise, distortion or crosstalk performance of the amplifier.

The loudspeaker output signals are passed to socket SK106 which connects to SK107 and onto the headphone output via the attenuation resistors R103 thru R106.

The hierarc hy con tai ning t he oth er sheet s i s self expla na tory. E ach of the port names shown on the top sheet connects t o the port of the same na me on the lower sheets.

L882 Circuit Sheet 2

This sheet contains the power supplies, the rear panel jack socket trigger circuits, the standby relay control and the ‘interface’ circuits between the output signals of the power amplifiers and the inputs expected by the micro processor.

The mains input enters the unit at SK203, with capacitors C205 and C206 acting as conducted RF suppression. The earth connection is passed on to the chassis (for safety reasons the chassis metalwork remains connected to mains power earth at all times). Switch SW200 is the voltage selector switch, allowing the unit to be operated in 230V or 115V mains countries by switching the dual-primary mains transformers between series and parallel winding. Varistors VR200 and VR201 act to prevent over-voltage surges from da maging the unit . If the user selec ts 115V opera tion and then connec ts the unit to a 230V sup ply, the varist ors will go to a low impedance and blow the primary fuses. Any very high voltage line transients will also be suppressed, helping to eliminate transformer isola tion breakdown.

Relay RLY200 switches the primary side of the mains transformer, allowing the micro to control th e on / off status of th e amplifier. Its contacts are snubbed by capacitors C207 and C208 (to eliminate switching spark transients and prolong relay lifespan). The primary windings of the toroidal mains transformer connect to SK204.

PCB mounted transformer TX200 is powered all the time that mains is presen t on S K203 , i rres p ective of t h e on / off st at u s of the amplifier. This is to ensure that the micro processor is always operational and can thus control the mains switching for the main amplifier. Secondary fuse F202 limits the current in the event of a failure mode, as the short circuit primary current of TX200 would be insufficient to blow the mains fuses.

Diodes D200 thru D203, C227 and IC201 provide the 5VDC supply which powers the micro and display PCB and the relay coils. C224 is to reduce diode noise being transmitted back through the leakage capacitance of TX200.

The mains transformer secondary winding is connected to SK200. This is a centre tapped winding, and is used with full bridge rectifier BR200 to produce the main positive and negative supplies for the power amp. C209 and C210 are the large reservoir capacitors, with C211 and C212 acting as high frequency decouplers. The main power supply rails and ground are accessible on SK205 for future module expansion.

The circuitry around SK201A and IC200 is to receive and demodulate remote control commands sent in via the rear panel jack socket. This is for mu lti-room applications. L200 and C200 form a parallel resonant circuit at approximately 37kHz. The output from this bandpass filter is passed into IC200A where it is ‘chopped’ and fed to IC200B to provide the output signal.

SK201B is a 13VDC signal trigger output which is active whenever the am plifier is powered up. R218 and DZ207 / C223 provide a reference voltage which is buffered by TR200. TR201 and R217 act as a current limit and prevent damage due to a short circuit on the output of SK201B. The maximum current is approximately 65mA.

TR203 and TR202 are a complementary Darlington pair which turn on mains relay RLY200 when activated by a signal from the microprocessor.

TR204 and its associat ed componen ts are to detec t whenever AC mains is present at the IEC socket. This is to notify the microprocessor i f the u ser ha s unplugged th e mains cord, s o that it can take the necessary action (muting all the outputs and switching off the mains rela y). The reser voir ca pacit ors should last at leas t 4 mains cycles which gives t he microproces sor plenty of time for a controlled shutdown.

TR204 forms a monostable circuit. Each cycle of AC turns on TR204 via R211. TR204 then ‘shunts’ C229 ensuring that it is kept at a low potential. If more than one mains cycle is missing, then R219 charges up C229 sufficiently to trigger Schmitt inverter IC202E thus pa ssing on a logic signal to the mi croprocessor. Th e use of a Schmitt inverter for IC202 is to ensure that the micro receives ‘clean’ logic levels - the hysteresis voltage (about 0.5V) is sufficient to prevent circuit noise from producing a string of ‘ghost’ signals wh en analogue levels are near the threshold point.

TH200 is a positive tempco thermistor placed adjacent to the heatsink on which the output transi stors are mounted. When the temperature of the thermistor exceeds 90 degrees Celsius the thermistor goes to a high impedance and so the input to IC202F goes low. This triggers a HIGH output to the micro indicating thermal overload .

The VI protection signals from the left and right channels pass into IC202A and IC202B respectively, to be ‘cleaned up’ via the Schmitt trigger. They are then NOR’d using TR205 which sends a HIGH signal t o t h e mi cr o in th e event of ei t h er c h an n el su ff eri ng a short circuit or current overload. Exactly the same approach is used for the DC fault lines using IC202C and IC202D.

L882 Circuit Sheet 3

This is the main audio power amplifier circuit. The amplifier is a class B design, which uses SAP ‘audio’ transistors in a symmetrical current feedback configuration. Input and feedback paths are DC c oupled and there is an active integrating s ervo to remove DC offsets from the output.

The basic principle of operation i s foll ows: The input signal is amplified by a factor of 2 in IC300A. This drives a 44 impedance to ground causing the supply pin currents to change with the signal level. These chan ging supply pin currents are then ‘reflected’ by a pair of complementary Wilson mirrors and passed on to a series of buffer transistors before being connected to the load . The ‘f eedba ck curr ent’ f lows back from the output terminal via R331 and R332 and attempts to provide the current necessary to allow IC300A to swing its output without drawing excessive current from its supply pins, thus making the change in supp ly current very small i ndeed. This i s why the term ‘current feedback’ is used - it is the current flowing in the feedback resis tors that sets the overall gain of the amplifier.

IC300B acts as an in vert in g int egra tor a nd its pu rp ose i s to remove DC from the loudspeaker output. Any positive DC offset will cause the output of IC300B to go negative, thus increasing the current in its n egative supply pin and pullin g the output voltage back towards zero. R330 and C317 set the time constant of this integrator (0.47 seconds) so that audio frequency components are ignored and only DC and subsonic frequencies are removed.

The input to the amplifier is limited to ±5.4V via back-to-back zener diodes D Z302 and DZ303. Th is is to prevent th e user from grossly overdriving the input to the amplifier and possibly causing damage. The diodes appear before series resistor R324 so that their variable capacitance does not introduce high frequency harmonic distortion.

R324, R327 and C316 act a s an input filter - this is a first order low pass filter with a corner frequency of around 340kHz to prevent RF sign als from being in jected into the fron t end of the amplifier. The corner frequency was ch osen such that the phase shift introduced is less than 5 at 20kHz (considered by the AES to be the minimum perceptible relative amount by the human ear). The input impedance of the amplifier is 23kW at DC, falling to around 14kW at 20kHz.

Operational amp lifier IC300A is actin g as a non-invertin g gain of 2, driving the input signal into a 44W impedance to ground via R322 and R337. Its output voltage will be an accurate amplificati on of its input voltage (i.e. the signal on pin 1 should look identic al t o th at on pi n 3 bu t a t twice t he am pli tude). The op amp is used in a slightly unusual configuration here, in that its power supply pins are used as a (current) output, and its output pin is used as a (current) feedback.

Transistors TR311 and TR303 supply the ±15V rails to the opamp, and act as cascades to pass its supply pin currents through to the current mirrors, which sit at a potentia l too high for the op-amp to be connected directly.

TR300, TR301 and TR321 form a PNP Wilson current mirror, which reflects the current sunk by the positive supply pin of IC300. Likewise TR314, TR315 and TR320 form an NPN Wilson current mirror, which reflects the current sou rced by the negative supply pin of IC300.

R315 thru R318 provide emitter degeneration of approximately 300mV for the current mirrors (as they pass about 3mA DC in quiescent c onditions) , to ensure ac curate oper ation ind ependent of the small variations between t he transistors in the current mirrors. They also ensure that the current passing down the next sta ge is reasonably constant as the internal temperature of the amplifier changes, swamp ing out small t hermal varia tions in the V mirror transistors.

R319 and R320 slightly decouple the rails to the current mirrors from the main power rails of the amp lifier, to allow the bootstra p circuit to operat e. The bootstrap consis ts of C302 and C306 with metal film power resistors R352 and R353. The bootstrap is provided to allow the power supply rails of the current mirrors to go up and down slightly with the output signal into the loudspeaker. This enables the driver stage to fully saturate the output transi stors and thu s give th e greatest power outp ut and b est thermal effici ency for any given power rail voltage. The voltage on the ‘inside’ end of R319 and R320 will vary by about 12 volts peak to peak at full output power, rising above the main power rails during signal peaks. C307 and C308 with R333 and R335 provi de the compensation necessary to ensure stability when the loop is closed. They are Miller capacitors which dramatically reduce the transimpedance (i.e. current to voltage gain) of the current mirrors at high frequencies. The present value of 47pF provides for a unity gain open loop ban dwidth of around 75MHz, whilst en suring a clos ed loop gain margin of around 6dB (note that gain margin in a current feedback design is not dependent on system bandwidth to a first order approximati on). R3 33 and R335 provid e a ‘zero’ in th e open loop frequency response which is tailored to give the best time domain performance (i.e. to make high frequency square waves look square with minimal ringing or overshoot).

DZ304 and C311 provide a fixed 4.7V bias voltage to allow the following st ages to opera te correc tly. C31 1 is ther e to ensure t hat

of the

both halves of the following stage receive an equal AC signal component at high frequency.

TR310 and TR307 are the ‘pre-driver’ transistors, which act to buffer the outputs from the preceding stage and drive the Darlington output power transistors. TR309 and R321 act as a current limit, to ensure that the emitter current of TR310 does not exceed 30mA in a fault condition. TR306 and R323 provide the same function for TR307.

R338 and R339 are to lo osely cou ple t he out puts of t he pre-d river stage to the inpu ts of the Da rlingt on power outpu t devices. This is so that the inbuilt temperature sensing diodes of the output transistors can accurately control the quiescent current of the output stage as the junction temperature of the power devices varies. C312 and C31 8 ensure tha t both halves of t he output sta ge receive an equal AC signal component.

The output t ransistors are TR318 and TR 319. These are Sanken SAP15N and SAP15P devices respectively. They are specially designed for audio power amplifier use. In addition to high current gain (Darlington with a typical h inbuilt emitter resistor (thick film power resistor of 0W22) and temperature sensing diodes which closely and rapidly track the V

versus temperature characteristic of the power transistors,

allowing for easy, fast-responding and reasonably accurate control of quiescent current (one of the major headaches of class B amplifier des ig n!)

RV300 is for fine trimming of the quiescent current. PL300 provides a convenient measuring point for this, which is shortcircuit protected in the event of a slip with the multimeter probe! All of the remaining circuitry to the right of TR318 and TR319 is essentially for output stage p r otection...

Transistors TR312 and TR304, alon g with th e network of resist ors and capacitors to which they are connected, provide instantaneous overload protection of the output stage. This is a conventional single slope VI protection scheme, which allows much greater current to be delivered into a rated load than into a short circuit. The values allow for 18A peak delivery (at clip) into a purely resistive load, 7A peak (at clip) into a purely capacitive load and around 4A peak in to a short circui t. R345, C303, R34 6 and C304 allow these values to be doubled for short transient bursts (approximately 2.7 milliseconds) so that impulsive musical transients can be delivered cleanly with minimal risk of damaging the output transistors.

TR313, TR302 and th eir associated components send a signal to the micropro cessor when the inst antaneous protect ion circuits are having to work ‘hard’ to prevent amplifier overload. This instructs the micro th at the user is sever ely abusing th e amplifier and will switch off the loudspeaker relays to prevent possible permanent damage. In reality, if you short circuit the outputs at any appreciable volume level, this circuit will trigger and the microprocessor will turn off the loudspeaker relays and send a signal to the user.

R308, R314 and C320 form a low pass filter from which the DC detection circuits can sense excessive DC at the loudspeaker outputs. If there i s any positive DC present, then TR316 will turn on, which turns on TR305 and thus activates the DC p rotection line to the micro, turning off the loudsp eaker relays.

If there is any negative DC present, then TR308 will turn on, which turns on TR317 whi ch then tu rns on TR305 in turn, cau sing the same effect.

R350 and C319 are the Zobel network which is provided to ensure the amplifier ‘sees’ a constant and resistive load at very high frequencies, to aid stability, although the amplifier will be stable without the Zobel fitted.

of 20,000) they provide an

C313 locally couples the ‘high frequency’ and loudspeaker ground returns together at the output to overcome the effects of track inductance back to the star point. C309 couples the ‘high frequency’ and signal grounds togeth er at the input for th e same reason.

D303 and D304 are ‘flyback’ diodes to protect the output transistors from reverse bias when the amplifier is heavily clipped into an inductive load (such as a loudspeaker voice coil!)

Sheet 4 is an identical copy of sheet 3 so I will not describe it separately.

L870 Phono Circuit Description

The Phono board is a simple single stage RIAA amplifier. It consists of two channels of high gain amplification, and switching between moving magnet (MM) and moving coil (MC) settings.

PSU The unit derives its ±15V regulated rails from the unit it is fitted

into with only local decoupling capacitors on board. Interface The unit connects to the host unit via a 8 way connector: Amplifier The left channel has designators beginning with 100, and the right

with 200. For the pu rposes of t his descri ption the left chann el will be described, as the right channel the same in all respects.

The amplifier is a small signal class A voltage feedback amplifier with switchable gain. The input consists of an actively loaded differential pair of very low noise PNP tran sistors (TR106,107). These transistors are very specific and should only be replaced with identical parts with the E grade high gain. TR100 & TR101 form a current source for the pair, which sets the qui escent current for the entire amplifier. The active load consists of TR110 & TR111, which forms part of a differential current mirror with TR112,113 & 114. This differential stage also has an active load (TR102 & TR103) to keep gain to a maximum .

Both of these d i ff eren ti a l st a ges a re des i gned t o h a ve a s mu ch gain as possible to enable the single stage design. The RIAA response is achieved in the feedback network: C101,110,111, 112,119,120,&R115,112. C115 is used to correct between MM & MC gains as the amplifier is non-inverting.

SW100 switches between MM & MC. Two poles of the switch change between the different loading required for each type of cartridge: R108 & C109 for MM, and added in parallel for MC R104 & C108. The oth er two poles change the feed back resistor value to alter the gain. MM: R105 and in parallel for MC R123.

The DC offset is c ontrolled by a non-i nverting servo b uilt around IC100. The amount of servo current is different for each gain setting via R111 (MM ) & R124(MC) so that the low frequency high pass point remains the same for both settings. However the high pass point for the circuit is set by C113. This gives a warp filter, stops DC startup thumps from upsetting DC coupled circuitry an d an approximation of the RIAA/ IEC curve (-2dB @ 20Hz).

The output is class A buffered by a dual mirror follower (TR104,105,108,109). The quiescent current is set up by D100 and R118,119.

Closed loop stability is achieved with C116,117, giving symmetrical slewing capability.

SK103 connects to the micro controller and display PCB. The 14 pin connector is numbered as follows:

No Name Type Description 1 +5V_D O/P 5 volt digital supply (for micro) 2 0V_D O/P Digital ground 3 +49V O/P Main power supply for VFD (via fusible resistor) 4 STANDBY I/P Mains relay control signal (HIGH = ON) 5 SPKR1 ON I/P Speaker 1 relay control signal (HIGH = ON) 6 SPKR2 ON I/P Speaker 2 relay control signal (HIGH = ON) 7 THERMPROT O/P Over temperature protect (HIGH = FAULT) 8 VIPROT O/P Short circuit protect (HIGH = FAULT) 9 DCPROT O/P DC offset protect (HIGH = FAULT) 10 AC PRESENT O/P Indicates AC mains is plugged in (HIGH = ON) 11 TRIGGER O/P 12V DC trigger input (HIGH = ON) 12 REMOTE O/P Demodulated RC5 remote input from rear panel 13 0V_D O/P Spare digital ground pin 14 +5V_D O/P Spare 5 volt digital supply pin

The ground naming convention is as follows:

Name Description 0V_D Digital ground (used for micro processor circuitry, display and interface) 0V_LS_R Right channel loudspeaker ground return 0V_SIG Signal ground (this is the ‘clean’ precision reference ground) 0V_PSU Power supply ground (high current pulses for the large reservoir caps) 0V_TRIG Ground return for the jack socket trigger and remote control circuit 0V_HF_R Decoupling ‘noisy’ ground for the right channel power amp 0V_LS_L Left channel loudspeaker ground return 0V_HF_L Decoupling ‘noisy’ ground for the left channel power amp

A85, P85, P85/3 Service Guide

Build History

ECO Number

00_1089 02/10/00 A85 – Fascia position changed to prevent display buttons sticking 00_1129 01/11/00 A85, P85, P85/3 – Improved stability under heavy clipping of amplifier R345,

00_1138 27/11/00 A85, P85, P85/3 – C303, C304, C403 changed from 10uF to 100uf capacitors –

01_1030 23/02/01 A85, P85, P85/3 – RV300, RV400 changed to 220R presets to make it easier to

01_1068 11/04/01 A85, P85, P85/3 – New output device clamp fitted to heatsink 01_1101 04/06/01 A85, P85, P85/3 – Sensitivity of DC offset detection circuit reduced – Power

01_1142 22/08/01 A85 – Preamp board upgraded from L866 to L937 01_1178 12/10/01 A85, P85, P85/3 – Speaker terminals changed from Camcon to 4mm binding

01_E014 28/11/01 A85 – Preamp board fuses F300, F301 up rated to 2A surface mount 02_E033 31/01/02 A85 – Extra pad F038 fitted under TX to stop TX coming loose in transit 02_E035 04/02/02 A85, P85, P85/3 – Main 20mm fuse rating changed to 4AT

Software History

ECO Number

01_1072 18/04/01 1.1 Remote standby action changed from turning unit completely off

01_1095 21/05/01 1.2 Delay added to start H8 start up routine (volume control chip) 01_1167 12/09/01 1.3 Volume chip read/write protocol changed 01_1179 26/10/01 2.0 Added the processor mode option 01_E011 23/11/01 2.1 Corrected the welcome message saving fault. This fault was

02_E048 15/02/02 2.2 Corrected the processor loop volume jump when v/c adjusted

Current Fuse Ratings (20/02/02)

Fuse Position Fuse Rating

Main Supply fuses - A85, P85, P85/3 2 x 4AT 20mm (Arcam part number C12406) PSU fuse F202 - A85, P85, P85/3 750mA surface mount (Arcam part number C3751) Preamp fuses F300, F301 – A85 2A surface mount (Arcam part number C3202)

Quiescent Current Setting

Left channel Measure points indicated on PCB -

Right channel Measure points indicated on PCB -

Date Description of Change

R346, R445, R446 changed from 100R to 0R link C307, C308, C407, C408 changed from 47P to 100P capacitors

this prevents protection circuit from operating when driving a 4 ohm load at low frequenc y

adjust the bias settings

amp cct R308, R408 changed to 22K - R314, R414 changed to 10K PSU surface mount fuse F202 up rated from 500mA to 750mA

post

Date Version Description of Change

to putting unit into standby

introduced with version 2.0 software

Adjust RV300 for 8.5mV cold or 12 mV when warm

Adjust RV400 for 8.5mV cold or 12 mV when warm

Fault Diagnostics

Fault Action

No power Check fuses

Check power supply rails

Unit functions ok but no audio Check preamp fuses

Check RL100A (volume control mute relay) Check +5V supply rail

Check mute signal line Volume cont rol locks up Check softwar e version is 2 .0 or higher DC offset Check equipment connected to amp for DC on the audio leads

Check alterations as per ECO 01_1101 have been fitted Unit fails to respond to commands Check ribbon cable from display to main board

Check ribbon cable from display to preamp board Unit gets very hot Check power stage IQ settings

Hints & Tips

To check software version press PHONO, TUNER, DVD buttons on the front panel simultaneously.

On issue 2 phono boards only, fit Kapton insulation tape to the phono stage PCB (rear panel end) to prevent track shorting to chassis.

Check all fuses are the correct rating.

Check DC offset alterations are fitted as per ECO 01_1101

To isolate a fault between the pre or power amp section press the PRE/PWR button on the rear panel to separate the two sections.

Check R100 on amp/psu board is not shorting to the track underneath (through plated via).

87654321

L882C3

L882C3_3.2.SCH L SIG 0V SIG 0V_LS_L 0V_HF_L +49V

-49V +5V_D

R SIG 0V_SIG 0V LS R 0V_HF_R +49V

-49V

INPUT 0V_SIG

0V_HF VPOS VNEG

L882C4

L882C4 3.2.SCH

INPUT 0V_SIG

0V_HF VPOS VNEG

VIPROT

DCPROT

OUTPUT0V_LS

VIPROT

DCPROT

OUTPUT0V_LS

VIPROT L DCPROT L LS L

VIPROT_R DCPROT_R LS R

0V D 0V_PSU

STANDBY VIPROT_L VIPROT_R 0V TRIG DCPROT L DCPROT_R

L882C2 L882C2 3.2.SCH

0V_D +5V(D) 0V_PSU PWRON

THPROT_uCVIPROT_L

VIPROT_R VIPROT_uC DCPROT_L

DCPROT_R

DCPROT_uC

AC_PRES0V_TRIG

TRG IN

VPOS VNEG

RC5 IN

+49V

-49V THERMPROT VIPROT AC PRESENT DCPROT REMOTE TRIGGER

0V TRIG

0V_D

5 6

1 2

SP100

STAR_8

TP121

0V SIG 0V HF R

0V_LS_R 0V LS L0V HF L 0V_PSU

FROM PREAMP

SK102

1 2 3 4

AMPCT4

0V_SIG

PHONO4G

EMC

SK104A

0V_SIG

SW100A 2PCO

PL100

C100 1N0 SM

0V_SIG

PL101

TP100

SK104B

PHONO4G

TP101

TP102

L SIG R SIG

LS L

0V_LS_L

LS R

SK105

HPSKT

LHC

RHC

+49V

RLY100C

D100

SK106 1 2 3 4

AMPCT4

TP118

5 2

3 1

6 7

TP119

TP120

R105 100R 1W CF

R103 330R 1W CF

R104 330R 1W CF

R106 100R 1W CF

SK107 1 2 3 4

AMPCT4

1N4003F

TR100 BD179

RLY G5Z-2A-E

TR101 BD179

R107 220R SM

RLY101C RLY G5Z-2A-E

R101 100R SM

R102 100R SM

R108 220R SM

D101 1N4003F

SPKR1 ON

SPKR2 ON

SK103

1 2 3 4 5 6 7 8 9 10 11 12 13 14

SW100B 2PCO

R100 10R MF

INTEGRATED / PRE-POWER MODE SELECT SWITCH

+5V D

+49V

STANDBY SPKR1 ON SPKR2 ON THERMPROT VIPROT DCPROT AC PRESENT TRIGGER REMOTE 0V_D

TP103

TP104

TP105

TP106

TP107

TP108

TP109

TP110

TP117

LS L

TP111 TP113 TP115

0V_LS_L

LS R

TP112 TP114 TP116

0V_LS_R

RLY100A

RLY G5Z-2A-E

RLY100B

RLY G5Z-2A-E

SK100A

Top+

Top-

CAMCON_G

SK101A

Top+

Top-

CAMCON_G

RLY101A

RLY G5Z-2A-E

RLY101B

RLY G5Z-2A-E

SK100B

Bot+

Bot-

CAMCON_G

SK101B

Bot+

Bot-

CAMCON_G

PCB

L882PB_3 EL

EARTH LEAD

8M101

EARTH LEAD

0V D

FFC 14W 2.54MM VER 8K7014

DRAWING TITLE

A85 amplifier and PSU - top sheet

23425

A & R Cambridge Ltd. Pembroke Avenue Denny Industrial Centre Waterbeach Cambridge CB5 9PB

Notes:

Filename

L882C1_3.2.PRJ

Circuit Diagram

01_1101 JR 6/4/01 POWER SUPPLY FUSES AND DC OFFSET 3.2 00_1134 MGM 17/11/00 NO CHANGE TO THIS SHEET 00_1138 JR 27/11/00 NO CHANGE TO THIS SHEET 00_1129 JR 1/11/00 NO CHANGE TO THIS SHEET 00_1115 JR 16/10/00 NO CHANGE TO THIS SHEET 00_1086 JR 19/9/00 NO CHANGE TO THIS SHEET

ECO No. DESCRIPTION OF CHANGE

Date Printed

INITIALS

6-Jun-2001

DATE

Drawn by:

J Reckless

1 4Sheet of

DRAWING NO.

L882C1

2.4

2.3

2.2

2.1

2.0

ISSUE

1 2 3 4 5 6 7 8

NEUTRAL

87654321

SK204

4 3

EMC Shield

BC200 TOOLING4.1

SH200 EMCMAINS

Green

SK202 CAGECLAMP1

C205 3N3 MAINS

TP206

N E L

TP200

TP207

EARTH

C234

SK203

IEC3 NO RIVETS

C206

3N3 MAINS

LIVENEUTRAL

LIVE

NEUTRAL

LIVE

SW200B VOL SEL SLIDE

F200

AS2A

SW200A VOL SEL SLIDE

F201

AS2A

2 1 5

MOLEXPWR8

RLY200A

DPDT5V

C207

3N3 MAINS

RLY200B

DPDT5V

C208

3N3 MAINS

8 7 6

TP202

TP201

TP210

TP203

1 0V

NF VR200

VDR 115V

2 3

VR201

VDR 115V

TX200

115V

115V TX 3VA 9301

HS200 TO220HS08REG

9VRMS

IC201

F202

T750mA SM

C224 6 7

100N CD

D200 1N4003F

D201 1N4003F

TP204

D202 1N4003F

C227 3300u 25V

D203 1N4003F

7805

Vin

C225 100N CD

GND

Vout

TP205

C226 100N CD

0V_D

+5V_D

+5V(D)

C228 1000u 10V

0V_D

220N X2 CLASS

R231 1M5 VR25

+49V

TP208

VPOS

SK205 1 2 3 4 5 6

AMPCT6

VNEG

SK200

3 2 1

MOLEXPWR6

BR200 BRGBU8D

6 5 4

C209 10,000u 63V

C210 10,000u 63V

C211 100N PC

0V_PSU

C212 100N PC

0V_PSU

TP209

MAINS WIRING AND AUXILIARY SUPPLY

9VRMS

R211 10K SM

TR204 BC849B

D206 BAS16W SM

0V_D

+5V_D

R219 1K8 SM

C229 22U EL

+5V_D

IC202E

74HC14D

MICROPROCESSOR SIGNALS INTERFACE

1011

R220

AC_PRES

10R SM

POWER AMP SUPPLY

-49V

CARRIER FILTER AND DEMODULATOR

R223 10K SM

R229 100K SM

C231

1N0 SM

5 6

R209 10K SM

R224 1K8 SM

R230 1K5 SM

R225 1K8 SM

IC200A

2 3

LM393A SM

C230 10N SM

R222 10K SM

TRG IN

SK201A

TP211

Near to PCB

JACK3.5X2

MODULATED RC5 REMOTE CONTROL INPUT

R226 470R SM

R227 1K0 SM

R228 100K SM

DZ204 4V7 350MW SM

RC5 IN

R208 10K SM

L200 27mH

IC200B

LM393A SM

C200 680P PP

+5V_D

IC200C LM393A SM

C232 100N SM

C233 10U EL

VIPROT_L

R201 1K0 SM

R202

VIPROT_R

1K0 SM

IC202G 74HC14D

C214 10N SM

0V_D

C201 100N SM

IC202A

1 2

74HC14D IC202B

3 4

C215 10N SM

74HC14D

C202 100N SM

0V_D

TH200 PTH90DEG

R205 1K0 SM

R213 4K7 SM

R214 4K7 SM

IC202F

74HC14D

C219 10N SM

+5V_D

R206 1K0 SM

0V_D

R221

1213

10R SM

TR205 BC856B

THPROT_uC

C203 100N SM

VIPROT_uC

C218 10N SM

+5V_D

0V_TRIG

+49V

R218

+5V_D

TR200 RLY200C DPDT5V

R200

STANDBY RELAY CONTROL

R212

PWRON

4K7 SM

1K0 SM

TR203 FMMT497

D205 BAS16W SM C213

10N SM

TR202 FMMT597

0V_D

TRIGGER OUTPUT APPROX 13.5VDC 60mA MAX CURRENT

SK201B

Far from PCB

JACK3.5X2

0V_TRIG

C235

1N0 SM

BD179

TP212

R210 10K SM

CAMCON_G SK101C

R217 10R SM

C222 10U EL

CHASS

TR201 FMMT497

10K SM

DZ207 15V 350MW SM

C223 10U EL

0V_TRIG

DRAWING TITLE

A85 amplifier - power supply and microcontroller interface

23425

A & R Cambridge Ltd. Pembroke Avenue Denny Industrial Centre Waterbeach Cambridge CB5 9PB

DCPROT_L

DCPROT_R

Notes:

Filename

L882C2 3.2.SCH

R203 1K0 SM

R204 1K0 SM

C216 10N SM

C217 10N SM

0V_D

Circuit Diagram

IC202C

5 6

74HC14D IC202D

74HC14D

R207 1K0 SM

0V_D

TR206 BC856B

DATE

C204 100N SM

DCPROT_uC

C220 100N SM

NO CHANGE TO THIS SHEET 2.1

Drawn by:

J Reckless

2 4Sheet of

DRAWING NO.

L882C2

2 4

2.2

ISSUE

R215 4K7 SM

R216 4K7 SM

01_1101 JR 6/4/01 POWER SUPPLY FUSES AND DC OFFSET 3.2 00_1134 MGM 17/11/00 NO CHANGE TO THIS SHEET 00_1138 JR 27/11/00 NO CHANGE TO THIS SHEET 2.3 00_1129 JR 1/11/00 NO CHANGE TO THIS SHEET 00_1115 JR 16/10/00 00_1086 JR 19-9-00 R231, C234, C235 ADDED FOR EMC 2.0

ECO No. DESCRIPTION OF CHANGE

Date Printed

C221 10N SM

INITIALS

6-Jun-2001

1 2 3 4 5 6 7 8

87654321

R319 100R SM

R300 10K SM

R315 100R SM

R316 100R SM

PRE DRIVER

VPOS

PNP CURRENT MIRROR

TR310 TR300 FMMT597

C300 100U EL

0V_HF

INPUT

DZ302 4V7 350MW SM

DZ303 4V7 350MW SM

0V SIG

0V_SIG

0V_HF

C301 100U EL

DZ300 15V 350MW SM

C310 100N SM

0V_SIG

INPUT FILTER V TO I AMP

R324 1K0 SM

C309 100N SM

0V_HF

DZ301 15V 350MW SM

R327 22K SM

0V_SIG

3 2

C316 470P PPW

C314 100N SM

TR311 FMMT497

R328 4K7 SM

TP302

IC300A

TL072CD

TP303

TR303 FMMT597

0V_SIG

C317

470N PE

IC300B

TL072CD

TP304

R322 22R SM

R337 22R SM

0V_SIG

R333 3K3 SM

100P SM

DC SERVO

R330

1M0 SM

0V_SIG

R331 1K5 SM

R332 1K8 SM

C311 100N PC

R335 3K3 SM

100P SM

C307

TR322 FMMT497

C308

TR301 FMMT597

TR321 FMMT597

R355 6K8 SM

R354 1K0 SM

TR320 FMMT497

TR309 FMMT497

R338 150R SM

BOOTSTRAP

C302 100U EL 100V

R352 470R 2W MF 5%

470R 2W MF 5% R353

C318 10U EL

C306 100U EL 100V

BOOTSTRAP

R339 150R SM

TR306 FMMT597

FMMT497

R321 22R SM

C312

10N SM

R323 22R SM

ADJ BIAS

RV300 100R PSET

D300 BAS16W SM

OUTPUT STAGE

TR318 SAP15N

TP305

R325 1K0 SM

R340 100K SM

R326 1K0 SM

TP306

TR319 SAP15P

OUTPUT STAGE

PL300

1 2

MEASURE BIAS (SET TO 16mV)

R341 330R SM

R342 330R SM

R343 100R SM

R344 100R SM

V-I PROTECTION

R334 22K SM

R347 100R SM

R345 0R0 SM

C303 100U EL

C304 100U EL

R346 0R0 SM

R348 100R SM

R336 22K SM

V-I PROTECTION

D301 BAS16W SM

TR312 FMMT497

TR304 FMMT597

D302 BAS16W SM

D303 1N4003F

DC OFFSET SIGNAL TO MICRO

D304 1N4003F

0V_HF

R349 100R SM

DCPROT

TR305 FMMT597

TP308

DZ306 4V7 350MW SM

R302 10K SM

R310 4K7 SM

C315 100N SM

R301 10K SM

R329 4K7 SM

TR313 FMMT497

R303 10K SM

R304 10K SM

0V_HF

TR316 FMMT497

TR302 FMMT597

R305 10K SM

R306 10K SM

DC OFFSET DETECTION

R307 10K SM

R313 10K SM

VI PROTECT SIGNAL TO MICRO

TP307

C305 10U EL

R308 22K SM

VIPROT

DZ305 4V7 350MW SM

0V_HF 0V_LS

C320 100U NP

2U2H LAC SMALL

R350 5R6 2W CF

C319 100N PE

R314 10K SM

R351 10R MF

L300

ZOBEL NETWORK

C313

100N SM

OUTPUT

0V LS

0V HF

TR314

R309 10K SM

FMMT497

NPN CURRENT MIRROR

R317

100R SM

R320 100R SM

TR315 FMMT497

R318 100R SM

TR307

FMMT597

PRE DRIVER

TR308 FMMT597

R311 10K SM

R312 10K SM

TR317 FMMT497

VNEG

01_1101 JR 6/4/01 POWER SUPPLY FUSES AND DC OFFSET 3.2

DRAWING TITLE

A85 amplifier - power output stage left

Circuit Diagram

23425

A & R Cambridge Ltd. Pembroke Avenue Denny Industrial Centre Waterbeach Cambridge CB5 9PB

1 2 3 4 5 6 7 8

Notes:

Filename

L882C3 3.2.SCH

00_1134 MGM 17/11/00 NO CHANGE TO THIS SHEET 00_1138 JR 27/11/00 C303 C304 FROM 10U TO 100U 2 3 00_1129 JR 1/11/00 R345 R346 C307 C308 VALUE CHANGES 00_1115 JR 16/10/00 R338 R339 CHANGED TO 150R 00_1086 JR 19/9/00 NO CHANGE TO THIS SHEET 2 0

ECO No. DESCRIPTION OF CHANGE

Date Printed

INITIALS

6-Jun-2001

DATE

Drawn by:

J Reckless

3 4Sheet of

DRAWING NO.

L882C3

2 4

2 2

2.1

ISSUE

87654321

R419 100R SM

R400 10K SM

R415 100R SM

R416 100R SM

PRE DRIVER

VPOS

PNP CURRENT MIRROR

TR410 TR400 FMMT597

C400 100U EL

0V_HF

INPUT

DZ402 4V7 350MW SM

DZ403 4V7 350MW SM

0V SIG

0V_SIG

0V_HF

C401 100U EL

DZ400 15V 350MW SM

C410 100N SM

0V_SIG

INPUT FILTER V TO I AMP

R424 1K0 SM

C409 100N SM

0V_HF

DZ401 15V 350MW SM

R427 22K SM

0V_SIG

3 2

C416 470P PPW C411

C414 100N SM

TR411 FMMT497

R428 4K7 SM

TP402

IC400A

TL072CD

TP403

TR403 FMMT597

0V_SIG

C417

470N PE

IC400B

TL072CD

TP404

R422 22R SM

R437 22R SM

0V_SIG

R433 3K3 SM

100P SM

DC SERVO

R430

1M0 SM

0V_SIG

R431 1K5 SM

R432 1K8 SM

TR422 FMMT497

100N PC

R435 3K3 SM

100P SM

C407

C408

TR401 FMMT597

TR421 FMMT597

R455 6K8 SM

R454 1K0 SM

TR420 FMMT497

TR409 FMMT497

R438 150R SM

BOOTSTRAP

C402 100U EL 100V

R452 470R 2W MF 5%

470R 2W MF 5%

R453

C418 10U EL

C406 100U EL 100V

BOOTSTRAP

R439 150R SM

TR406 FMMT597

FMMT497

R421 22R SM

C412

10N SM

R423 22R SM

ADJ BIAS

RV400 100R PSET

D400 BAS16W SM

OUTPUT STAGE

TR418 SAP15N

TP405

R425 1K0 SM

R440 100K SM

R426 1K0 SM

TP406

TR419 SAP15P

OUTPUT STAGE

PL400

1 2

MEASURE BIAS (SET TO 16 mV)

R441 330R SM

R442 330R SM

R443 100R SM

R444 100R SM

V-I PROTECTION

R434 22K SM

R447 100R SM

R445 0R0 SM

C403 100U EL

C404 100U EL

R446 0R0 SM

R448 100R SM

R436 22K SM

V-I PROTECTION

D401 BAS16W SM

TR412 FMMT497

TR404 FMMT597

D402 BAS16W SM

D403 1N4003F

DC OFFSET SIGNAL TO MICRO

D404 1N4003F

0V_HF

R449 100R SM

DCPROT

TR405 FMMT597

TP408

DZ406 4V7 350MW SM

R402 10K SM

R410 4K7 SM

C415 100N SM

R401 10K SM

R429 4K7 SM

TR413 FMMT497

R403 10K SM

R404 10K SM

0V_HF

TR416 FMMT497

TR402 FMMT597

R405 10K SM

R406 10K SM

DC OFFSET DETECTION

R407 10K SM

R413 10K SM

VI PROTECT SIGNAL TO MICRO

TP407

C405 10U EL

R408 22K SM

VIPROT

DZ405 4V7 350MW SM

0V_HF 0V_LS

C420 100U NP

R450 5R6 2W CF

C419 100N PE

R414 10K SM

R451 10R MF

L400

2U2H LAC SMALL

ZOBEL NETWORK

C413

100N SM

OUTPUT

0V LS

0V HF

TR414

R409 10K SM

FMMT497

NPN CURRENT MIRROR

R417

100R SM

R420 100R SM

TR415 FMMT497

R418 100R SM

TR407

FMMT597

PRE DRIVER

TR408 FMMT597

R411 10K SM

R412 10K SM

TR417 FMMT497

VNEG

01_1101 JR 6/4/01 POWER SUPPLY FUSES AND DC OFFSET 3.2

DRAWING TITLE

A85 amplifier - power output stage right

Circuit Diagram

23425

A & R Cambridge Ltd. Pembroke Avenue Denny Industrial Centre Waterbeach Cambridge CB5 9PB

1 2 3 4 5 6 7 8

Notes:

Filename

L882C4 3.2.SCH

00_1134 MGM 17/11/00 L300 L400 CHANGED TO 7D002C 00_1138 JR 27/11/00 C403 C404 FROM 10U TO 100U 2 3 00_1129 JR 1/11/00 R435 R436 C407 C408 VALUE CHANGES 00_1115 JR 16/10/00 R438 R439 CHANGED TO 150R 00_1086 JR 19/9/00 NO CHANGE TO THIS SHEET 2 0

ECO No. DESCRIPTION OF CHANGE

Date Printed

INITIALS

6-Jun-2001

DATE

Drawn by:

J Reckless

4 4Sheet of

DRAWING NO.

L882C4

2 4

2 2

2.1

ISSUE

DISP1 DISP SSV-07MS09

87654321

10K SM

100N SM

Test pad change for issue 3: Q_23= SO (was STBLED) Q_9=SI (was GND)

DATA /O

SK1

FFC8H SM

R14 4K7 SM

+5V

SW3 PAUSE

R15 1K0 SM

R11 10K SM

Q3 BC847B

Q_26

Q5 BC856B

Q6 BC846B

R12 10K SM

BZX284-C5V6

R7 33K SM

SW4 PLAY

Q4 BC847B

VKK

CATHODE BIAS CCT

IRIRQ

SW5 STOP

C5 10U EL SM

SW6 OPEN

Q_18

R5 470R SM

LED2 LED GREEN3 1MM

HDCD

10U EL SM

(was POWER) SW7

FWD>>

SO SI

SCK CS

Q_29

Q_1

Q_2

Q_3

Q_4

BAS16W SM

R16 1K0 SM

R6 1K0 SM

HDCDLED

STBLED

1N0 SM

1 2 3 4 5 6 7 8

9 10 11

+5V

VKK_D

VKK_CK

VSS

Q1 BC856B

+5V

38L439L340L241L142

VDD

Q2 BC847B

Q_24

Q_25

OSC

SW1 SW2 SW3 SW4 SO SI VSS SCK CS K1 K2

K312K413VDD14S115S216S317S418S519S620S721S8

C2 100N SM

DRAWING TITLE

DVD DISPLAY PCB

A & R Cambridge Ltd. Pembroke Avenue Denny Industrial Centre Waterbeach Cambridge CB5 9PB

F11F12G15G26G37G48G59G610G7

C3 100N SM

G1 G2 G3

G434G335G236G1

G6 S16/G7 S15/G8 S14/G9

S13/G10

VEE

S12/G11

S11 S10

LED1

On=Green Standby=red

LED RED/GRN 3MM

Notes

Filename

J:\ECO wip\L886 DV88 Display board correct R4 cock-up\L8863\L8863.0a.ddb - L886 3.0a.sch

30 29 28 27

VKK

26 25 24 23

BU2872AK

SEG8 SEG7 SEG6 SEG5 SEG4 SEG3 SEG2 SEG1

R4 220R SM

FIX1 FIX NG HOLE

Circuit Diagram

SEG15 SEG14 SEG13

SEG12 SEG11 SEG10 SEG9

74HC74 SM

FIX2 FIXING HOLE

GND

+5V

VCC

Z2C

C8 100N SM

FIX3 FIX NG HOLE

FIX4 FIXING HOLE

ECO No. DESCRIPTION OF CHANGE

Date Printed

S125S226S327S428S529S630S731S832S933S1034S1135S1236S1337S1438S1539F242F2

F2F1

PCB

L886PB_3

SP1

IR RX SUPPORT PAD

PHOTO_STRIP

EL1

UPDATE_BOX

DD2

CLK

Display clips: PCB footprint is called E882PM This footprint will accept either E874PM (current clip) or E882PM (new clip not designed yet) This part type currently calls for p/n E874PM, change to E882PM when new clip is available

INITIALS

Z2B

74HC74 SM

LC1

VFD CLIP

E882PM E874PM

DVD DISPLAY CLIP

PG 17/11/00 Correct error R4 is 1206 not 0805 3.0a PG00_1082 14/09/00 Change RX1 to l/p part, test pad changes, display clip, R4 VALUE 3.0 CL 23/08/00 MINOR MODIFICATIONS 2.0 CL 31/07/00 PRODUCTION RELEASE 1.0

DATE

LC2

VFD CL P

E882PM E874PM

DVD DISPLAY CL P

Drawn by:

PG17-Nov-2000

DD6

CLOGO

Layout by

Cliff

1 1Sheet of

DRILL_DWG

DRAWING NO.

10K SM

SBX1610-52/PIC-26043TM2

Q_7

Q_30

5 6 7 8

1 2 3 4 5 6 7 8

Q_27

Q_28

+5V

R13 1M0 SM

RX1

O/P

+5V

O/P

GND1Case

Case

GND +5V

DUAL FOOTPRINT

+5V

R8 4K7 SM

Q_23

SO IR RQ CS SCK SI

Q_9

2 3

C7 100N SM

Pwr in

+5V

SW1 SKIP>

SW8 <<RWD

(was MENU)

+5V

CLK

R9 10K SM

SK2

Q_10

Q_11

Q_12

Q_13

4 5

Q_14

AMPCT6H

SW2 <SKIP

VKK switching CCT

Z2A

74HC74 SM

VKKIN VKK

R10 10K SM

VKKIN

VKK = -19.5V F1= -13.9V F2 = -9 6V

PCB

R RX

SUPPORT PAD

DD1

PCB MATERIAL

FR4, 1 OZ Cu

FR4_1OZ

Photo Strip

Update Box

Drilling

Detail

DD3

A2 Horizontal

Paper Marker

DD_A3H

DD4

A2 Vertical

Paper Marker

DD_A3V

FD_1

F DUCIAL

FD_2

FIDUCIAL

ISSUE

L886_3

4321

Main signal path L937C2 1.1.SCH

Power supply L937C3 1.1.SCH

USE EXCLUDE NF WHEN USING RUNOUT SHEET PROGRAM

DRAWING TITLE

Integrated amplifier preamp

PCB1

PCB

L937PB_1

23425

A & R Cambridge Ltd. Pembroke Avenue

Notes:

Denny Industrial Centre Waterbeach Cambridge CB5 9PB

1 2 3 4

Filename

J:\Change_Control\ECO_AGENDA\01_E014 Fuse changes on A32 preamp\L937_1.1.ddb - Documents\Schematic\L937C1_1.0.PRJ

Circuit Diagram

01_E014 JBR 28/11/01 Fuses uprated to 2A 1.1 01_1142 JBR 14/8/01 First production release 1.0

ECO No. DESCRIPTION OF CHANGE

Date Printed

INITIALS

28-Nov-2001

DATE

Drawn by:

JBR

1 3Sheet of

DRAWING NO.

L937C1

ISSUE

87654321

D100

+15V -15V

BAV99W DUAL SM

SK2A

CDL1 CDL

0V_SIG

D101 BAV99W DUAL SM

D102 BAV99W DUAL SM

0V_SIG

TUNR1

D106 BAV99W DUAL SM

D107 BAV99W DUAL SM

0V_SIG

D108 BAV99W DUAL SM

D112 BAV99W DUAL SM

0V_SIG

D113 BAV99W DUAL SM

D114 BAV99W DUAL SM

0V_SIG

D115 BAV99W DUAL SM

D116 BAV99W DUAL SM

0V_SIG

D117 BAV99W DUAL SM

R100 1K0 SM

R101 1K0 SM

R102 1K0 SM

R125 1K0 SM

R126 1K0 SM

R127 1K0 SM

R156 1K0 SM

R157 1K0 SM

R158 1K0 SM

R189 1K0 SM

R190 1K0 SM

R191 1K0 SM

0V_SIG

R103 100K SM

CDR

R104 100K SM

TUNL

R105 100K SM

TUNR

R128 100K SM

AVL

R129 100K SM

AVR

R130 100K SM

DVDL

R159 100K SM

DVDR

R160 100K SM

TAPEIL

R161 100K SM

TAPEIR

R192 100K SM

VCRIL

R193 100K SM

VCRIR

R194 100K SM

CD L

470P FKP2

CD R

0V_SIG

TUNER L

TUNER R

0V_SIG

AV L

AV R

0V_SIG

DVD L

DVD R

TAPE IN L

TAPE IN R

VCR IN L

VCR IN R

C101

C102 470P FKP2

C103 470P FKP2

C122 470P FKP2

C123 470P FKP2

C124 470P FKP2

C140 470P FKP2

C141 470P FKP2

C142 470P FKP2

C161 470P FKP2

C162 470P FKP2

C163 470P FKP2

CD INPUT

EMC

C100 1N0 SM

0V_SIG

TUNER INPUT

CDR1

PHONO4G

+15V -15V

SK2B

TUNL1

PHONO4G

+15V -15V

AV INPUT

SK3A

AVL1

EMC

C121 1N0 SM

0V_SIG

DVD INPUT

TAPE INPUT

AVR1

PHONO4G

+15V -15V

SK3B

DVDL1

DVDR1

PHONO4G

+15V -15V

SK4A

TAPEIL1

EMC

C139 1N0 SM

0V_SIG

VCR INPUT

C160 1N0 SM

0V_SIG

TAPEIR1

PHONO4G

+15V -15V

SK5A

VCRIL1

EMC

VCRIR1

PHONO4G

+15V -15V

1 2 3 4 5 6 7 8

+15V

-15V

+15V

-15V

+15V

-15V

0V_SIG

C106 100N SM

C107 100N SM

C125 100N SM

C126 100N SM

C127 100N SM

C128 100N SM

0V_SIG

+15V

C104 100N SM

C105 100N SM

-15V

0V_SIG

+15V

-15V

+15V

C145 100N SM

C146 100N SM

-15V

AUX INPUT

C164 1N0 SM

VCR2

C143 100N SM

C144 100N SM

PHONO2G

AUX L CD L TUNER L AV L DVD L

VCR IN L MODULE L

0V_SIG

AUX R CD R TUNER R AV R DVD R

VCR IN R MODULE R

TAPE 2

AUX L CD L TUNER L AV L DVD L TAPE IN L

MODULE L

VCR01

AUX R CD R TUNER R AV R DVD R TAPE IN R

MODULE R

AUX L CD L TUNER L AV L DVD L TAPE IN L VCR IN L MODULE L

LIST2

AUX R CD R TUNER R AV R DVD R TAPE IN R VCR IN R MODULE R

LISTEN0

LISTEN1

LISTEN2

D118 BAV99W DUAL SM

AUXIL1

TAPE 1

TAPE 2

TAPE 0

TAPE 1

LIST1

TAPE 0

0V_SIG

VCR 2

0V_SIG

VCR 2

0V_SIG

LIST0

VCR 1

R162 22K SM

R163 22K SM

R164 22K SM

R165 22K SM

R166 22K SM

R167 22K SM

R168 22K SM

R169 22K SM

TAP0

TAP1

TAP2

TAPE0

TAPE1

TAPE2

VCR11

VCR21

VCR0

VCR1

+15V -15V

SK6

EMC

0V_SIG

AUXIR1

+15V -15V

D119 BAV99W DUAL SM

VCR 0

R195 1K0 SM

R196 1K0 SM

+5V

-15V

LISTEN 0 LISTEN 1 LISTEN 2

0V_SIG

LISTEN 0 LISTEN 1 LISTEN 2

0V_SIG

Z100 4 5 6 7

12 11 10

9 2

16 15

DG408DY

Z101 4 5 6 7

12 11 10

9 2

16 15

DG408DY

Z102 4 5 6 7

12 11 10

9 2

16 15

DG408DY

Z103 4 5 6 7

12 11 10

9 2

16 15

DG408DY R170

22K SM R171

22K SM R172

22K SM R173

22K SM

R174 22K SM

R175 22K SM

R176 22K SM

R177 22K SM

AUXL

0V_SIG

X0 X1 X2 X3 X4 X5 X6 X7

EN A0 A1 A2

GND V-

X0 X1 X2 X3 X4 X5 X6 X7

EN A0 A1 A2

GND V-

X0 X1 X2 X3 X4 X5 X6 X7

EN A0 A1 A2

GND V-

X0 X1 X2 X3 X4 X5 X6 X7

EN A0 A1 A2

GND V-

+5V

R197 100K SM

AUXR

R198 100K SM

-15V

AUX R

AUX L

V+

4 5 6

7 12 11 10

1 16 15

7 12 11 10

1 16 15

+15V 13 8

R106 1M0 SM

0V_SIG

+15V-15V 13 8

R107 1M0 SM

0V_SIG

+15V 13 8

R131 1M0 SM

0V_SIG

+15V-15V 13 8

R132 1M0 SM

0V_SIG

Z104

V+ X1 X2 X3 X4 X5 X6 X7

EN A0 A1 A2

GND V-

DG408DY Z105

V+ X1 X2 X3 X4 X5 X6 X7

EN A0 A1 A2

GND V-

DG408DY

SK103

1 2 3 4 5 6 7

TO PHONO PCB

AMPCT8

C165

0V_SIG

470P FKP2

C166 470P FKP2

AUX R

AUX L

13 8

+15V

+15V1

0V_HF

0V_SIG

-15V1

-15V

3 2

5 6

3 2

5 6

C147 100N PE

C167 100N PE

+15V

AUXR1

AUXL1

+15V -15V

D103 Z109A TL072 SM

Z109B TL072 SM

Z110A TL072 SM

Z110B TL072 SM

C148

22P SM R178 22K SM

Z115A

OPA2134PA SM

C149

22P SM R179 22K SM

Z116A

OPA2134PA SM

Z109C

TL072 SM

Z113C

TL072 SM

BAV99W DUAL SM

R108

47R SM

C108 100P SM

+15V -15V

D104

BAV99W DUAL SM

R109

47R SM

C109 100P SM

+15V -15V

D109

BAV99W DUAL SM

R133

47R SM

C129 100P SM

+15V -15V

D110

BAV99W DUAL SM

R134

47R SM

C130 100P SM

Z115_1A

R180 100K SM

R199 100K SM

-15V

OPA2134PA SM +15V

OPA2134PA SM

C168 100N SM

0V_SIG 0V_SIG 0V_SIG 0V_SIG

C169 100N SM

-15V2

C170 100N SM

0V_SIG 0V_SIG 0V_SIG 0V_SIG 0V_SIG

C171 100N SM

C150

470N PE

-15V C151

470N PE

TAPE02

Z115B

C188 10U EL

C189 10U EL

Z116_1A

Z116B

TL072 SM

TAPEO1

0V_SIG

VCRO1

0V_SIG

VCR02

Z110C

Z114C

VCR OUTPUT

6 5

0V_SIG

6 5

0V_SIG

SK4B

PHONO4G

SK5B

PHONO4G

R183 1M0 SM

R184 1M0 SM

C172 100N SM

C173 100N SM

C174 100N SM

C175 100N SM

TAPE OUTPUT

TONE*

C152 100N SM

TONE*

Z111C

TL072 SM

Z115C

OPA2134PA SM

0V_SIG

C176 100N SM

C177 100N SM

C178 100N SM

C179 100N SM

1 2 3 4

6 7 8

C110 100U EL

0V_SIG

C131 100U EL

0V_SIG

Z106

SEL1 D1 S1 VGND5VL S4 D4 SEL4

DG413DY

+15V2

Z112C

TL072 SM

OPA2134PA SM

SEL2

SEL3

+15V

Z116C

+5V

R110 2K2 SM

R112 22K SM

R111 2K2 SM

Z115_1B

+5V

R135 2K2 SM

R137 22K SM

R136 2K2 SM

Z116_1B

TONE

+5V

C180 100N SM

C181 100N SM

C182 100N SM

C183 100N SM

/TONE

TONE*

OPA2134PA SM

16 15

V+

12 11

Z111_3

Z113_3

+15V-15V

0V_SIG

+15V

Z117C

R113 22K SM

R138 22K SM

Z111A TL072 SM

3 2

C111 10U CERAFINE

Z113A TL072 SM

3 2

C132 10U CERAFINE

Z107_4

C153 100N SM

Z107_13

0V_SIG

0V_SDATA

0V_SLOAD

0V_SCLK

C184 100N SM

C185 100N SM

C154 10U EL

Z111_7

Z113_7

0V_SIG

R182 100R SM

R200 2R2 SM R201 2R2 SM R202 2R2 SM

Z111_1

Z113_1

C155 100N SM

D105 BAV99W DUAL SM

0V_SIG

1618

Z108D 17

DS1844

5 6

R115 2K7 SM

R116 2K7 SM

D111 BAV99W DUAL SM

Z108B 7

DS1844

5 6

R140 2K7 SM

R141 2K7 SM

0V_SIG

C156 100N SM

0V_SIG

AVCC

SCLK

SDATA

+5V

C186

100N SM

0V_SIG

Z112_3

Z108_19

C113 470N PE

Z114_3

Z108_3

C134 470N PE

LFO

LMO RFO

RMO

R181 10K SM

DS1844

0V_SIG

DS1844

0V_SIG

1519

C157 100U EL

2 14

Z107 VSDVC

Z108A 14

0V_SIG

Z108C 4

0V_SIG

R117 5K6 SM

R142 5K6 SM

C187 10U EL

C114 CFKP2 63V 2N2

3 2

C135 CFKP2 63V 2N2

+15V

Z117A

OPA2134PA SM

Z117B

OPA2134PA SM

R114 22K SM

7 Z111B

TL072 SM

C112

470N PE

C192

470N PE

+5V

R139 22K SM

7 Z113B

TL072 SM

C133

470N PE

C193

470N PE

+5V

R185 22R SM

Z107_1

DVCC

LIN

LGND

RIN

RGND

DGND11XCS6DATA9CCLK10XMUTE8AGND

SLOAD

DRAWING TITLE

Integrated amplifier preamp - main signal path

23425

A & R Cambridge Ltd. Pembroke Avenue Denny Industrial Centre Waterbeach Cambridge CB5 9PB

Notes:

Filename

J:\Change Control\ECO AGENDA\01 E014 Fuse changes on A32 preamp\L937 1.1.ddb Documents\Schematic\L937C2 1.0 SCH

Circuit Diagram

Z112A TL072 SM

3 2

R118 22K SM

Z114A TL072 SM

C136

22P SM

R143 22K SM

C190 10U EL

C191 10U EL

-15V

C158 22P SM

C159 22P SM

D120 BAS16W SM

C115

22P SM

Z112B TL072 SM

Z112_1

Z114B

Z114_1

TL072 SM

+15V -15V

0V_SIG

SK102_1

R186 47R SM

SK102_3

R187 47R SM

+5V

+-RLY100C

RLY DPDT 5V SM

Q100 BC849B

0V_D

Z112_7

0V_SIG

R144 22K SM

R145 22K SM

C137 10U CERAFINE

0V_SIG

D121 BAV99W DUAL SM

RLY DPDT 5V SM

0V_SIG

R203 4K7 SM

01_E014 JBR 28/11/01 Fuses uprated to 2A 1.1 01_1142 JBR 14/8/01 First production release 1.0

ECO No. DESCRIPTION OF CHANGE

Date Printed

C117

10U CERAFINE

R119 22K SM

R120 22K SM

C116 10U CERAFINE

C138

10U CERAFINE

D122 BAV99W DUAL SM

RLY100A

MUTE*

INITIALS

Z106_14

R121 22K SM

Z106_11Z114_7

R146 22K SM

RLY100B

RLY DPDT 5V SM

DATE

SCLK

SDATA

TONEID

0V_D

0V_TONEID

SK102 1 2 3 4

AMPCT4 TO POWER AMP I/P

Drawn by:

JBR28-Nov-2001

SCLK

SDATA

TONEID

IC DS1844

0V_TONEID

0V_SDATA

0V_SCLK

LISTEN 0 LISTEN 1 LISTEN 2 VCR 0 VCR 1 VCR 2 TAPE 0 TAPE 1 TAPE 2

TONE* TONEID

0V_SDATA

13 12

R122 2R2 SM

R124 2R2 SM

R123 2R2 SM

MUTE*

SDATA

0V_SLOAD

0V_SIG

2 3Sheet of

+5V

CLK DIN RST

R147 22K SM

R148 22K SM

R149 22K SM

R150 22K SM

SLOAD

0V_SCLK

R188

10K SM

Z108E

VCC

R/W

DOUT

GND

0V_SIG

SCLK

AUX L AUX R CD L CD R TUNER L TUNER R AV L AV R DVD L DVD R TAPE IN L TAPE IN R VCR IN L VCR IN R MODULE L

MODULE R

0V_MODULE

DRAWING NO.

C118 100N SM

R204 10K SM

C119 10N SM

R151 22K SM

R152 22K SM

R153 22K SM

R154 22K SM

R155 22K SM

FFC22V1MM

L937C2

C120 10U EL

SK100 1 2 3 4 5 6 7 8

9 10 11 12 13 14 15 16 17

TO MICRO / DISPLAY PCB

18 19 20 21 22

SK101

9 10 11 12 13 14 15 16 17 18 19 20

TO PLUG IN MODULE PCB 21 22

23 24 25 26 27 28 29 30

FFC30V SM

ISSUE

4321

D302

BAS16W SM

Q305 2SA1964

SK300 MOLEXPWR4

F300

T2A SM

F301

T2A SM

AC1

C307 470N PE

AC2

D300 S1D

C308 100N SM

C309 100N SM

D301 S1D

UR+

C300 1000u 35V

Q300 J112

R300 330R SM

C314 1N0 PP

C315 1N0 PP

Q303 J112

Q306 BC846B

D310+

C302 220U EL

C312 220U EL

D311-

D310 15V 350MW SM

D311 15V 350MW SM

+15V

+15V3

C304 100N SM

C303 3300u 25V

C313 3300u 25V

Z301 LM317T

Vin

0V_PSU

D304

BAS16W SM

Vout

ADJ

+3.75V

R302 1K2 SM

R307 220R SM

C305 10U EL

-15V

D305 BAS16W SM

+15V

0V_PSU

0V_MODULE

R303 470R SM

SK301 1 2 3 4

IDC4S

+5V

C306 470U EL 25V

D306 S1D

D307 S1D

UR-

C310 1000u 35V

R304 330R SM

Q301 2SC5248

D308

BAS16W SM

Q307 BC856B

-15V

-15V3

SP300 STAR POINT 4

0V_HF 0V_MODULE

0V_PSU

0V SIG

0V_SIG

DRAWING TITLE

Integrated amplifier preamp - power supply

23425

Notes:

Circuit Diagram

01_E014 JBR 28/11/01 Fuses uprated to 2A 1.1

A & R Cambridge Ltd. Pembroke Avenue Denny Industrial Centre Waterbeach Cambridge CB5 9PB

1 2 3 4

Filename

J:\Change_Control\ECO_AGENDA\01_E014 Fuse changes on A32 preamp\L937_1.1.ddb - Documents\Schematic\L937C3_1.0.SCH

01_1142 JBR 14/8/01 First production release 1.0

ECO No. DESCRIPTION OF CHANGE

Date Printed

INITIALS

28-Nov-2001

DATE

Drawn by:

JBR

3 3Sheet of

DRAWING NO.

L937C3

ISSUE

+ 37 hidden pages