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Service Manual

P7
Issue 1.0

FMJ P7 7-Channel Amplifier

ARCAM

Contents List

Section

Issue

Technical specifications
! ! Technical specification Rear panel silk screen -

Amplifier board L924
! ! ! ! Circuit description Component overlay Parts list Circuit diagrams 1.0 1.1 1.1

Controller board L925
! ! ! ! Circuit description Component overlay Parts list Circuit diagrams 1.0 1.2 1.2

Transformer specifications
! ! ! ! L911TX L912TX L920TX L921TX 1.0 1.0 1.0 1.0

Mechanical
! ! General assembly parts list Assembly diagrams Front panel TX tray Rear panel Chassis -

-

Technical Specifications

Contents

!

Technical specifications

!

Rear panel silk screen

Technical Specifications

All measurements are with 230V/50Hz mains power Continuous output power All channels driven, 20Hz ­ 20Khz, 8 ohm All channels driven, 20Hz ­ 20kHz, 4 ohm One or two channels driven at 1kHz, 8 ohm One or two channels driven at 1kHz, 4 ohm One or two channels driven at 1kHz, 3.2 ohm

150W per channel 230W per channel 160W per channel 250W per channel 300W per channel

1.05kW total 1.62kW total

Peak output current capability

25A per channel

Total harmonic distortion At any level up to rated power, into 4 or 8 ohms

<0.05% (20Hz ­ 20kHz) Typically <0.005% at 1kHz

Frequency response

+-0.2dB (20Hz ­ 20 kHz) -1dB at 1Hz and 100kHz

Residual hum and noise Referenced to full power

-122dB, 20Hz ­ 20kHz, unweighted

Voltage gain

x 28.3 (1V input gives 100W/8 ohm output)

Input impedance

22k ohm in parallel with 470pF

Output impedance

50m Ohm at 20Hz, 1kHz 120m ohm at 20kHz

Power requirements

115V or 230VAC, 50/60Hz, 3kW maximum via heavy duty IEC mains inlet A soft start system eliminates large inrush currents at switch on

Dimensions

W430 x D450 x H180 mm

Weight

31kg (68 Ib) nett 35kg (77 Ib) packed

7 RS BACK

6 R SURR

5 RIGHT

4 CENTRE

3 LEFT

2 L SURR

1 LS BACK

230V

POWER INLET

50 ­ 60 Hz 3700 VA MAX

~

12V TRIGGER IN

CAUTION ­ SHOCK HAZARD, DO NOT OPEN. ACHTUNG ­ VOR OEFFNEN DES GERAETES NETZSTECKER ZIEHEN. ATTENTION ­ RISQUE DE CHOC, NE PAS ENLEVER. PRECAUCION ­ PELIGRO DESCARGA, NO ABRIR.
RADIO INTERFERENCE (USA) THIS PRODUCT COMPLIES WITH PART 15 OF FCC RULES, OPERATION IS SUBJECT TO THE FOLLOWING CONDITIONS; (1) THIS DEVICE MAY NOT CAUSE HARMFUL INTERFERENCE (2) THIS DEVICE MUST ACCEPT ANY INTERFERENCE RECEIVED, INCLUDING INTERFERENCE THAT MAY CAUSE UNDESIRED OPERATION.

SERIAL No. LABEL
DESIGNED & MADE IN THE UK BY: A & R CAMBRIDGE LTD, WATERBEACH, CAMBRIDGE, CB5 9PB.

WARNING: THIS APPLIANCE MUST BE EARTHED.

THIS PRODUCT IS CERTIFIED BY THE MANUFACTURER TO COMPLY WITH DHHS RULE 21 CFR SUBPART J APPLICABLE AT THE DATE OF MANUFACTURE.

Amplifier Board L924
Contents

!

Circuit description

!

Component overlay

!

Parts list

!

Circuit diagrams

P7 Amplifier Module
Circuit Description Refer to L924 circuit diagrams Introduction
L924 is the power amplifier module for the P7 multichannel amplifier. There are 7 identical modules in the P7. The circuit design is based on the A85 / A32 output stage topology. The main features of the amplifier module are as follows: · · · · · · · · · · · · · Preset `THX' gain (29dB closed loop gain). 0dBV input signal corresponds to 100 watts into 8 output power Capable of producing 150 watts of sinusoidal output power into an 8 resistive load (with greater than 250W into 3.2 subject to thermal dissipation limits) Relay coupled output for silent power on / off and load protection Opto-isolated fault and control lines to the microprocessor PCB (to avoid hum loops and instability, to improve EMC performance and crosstalk) DC coupled signal path with integrating servo to remove residual DC errors Instantaneous load protection Mono block design (each channel is electrically isolated from all others and has independent power supply windings on the mains transformer) Integrated modular heatsink for good thermal performance and ease of assembly / servicing Low harmonic and intermodulation distortion Flat frequency response Fast (and symmetrical) slew rate High damping factor Unconditionally stable into loads of up to ±90° phase angle

The line `NFB' provides for a portion of the negative feedback of the amplifier to be taken on the load side of RLY101. The components that allow for this (R236 thru R239) are not presently fitted, meaning that RLY101 is not included in the feedback loop. SK104 connects to the microcontroller PCB. Note that all signals on this connector are electrically isolated from the amplifier circuit itself, via either opto isolators or the relay coil of RLY101. The 10pin connector has the following signals:

SK104
Pin 1 2 Type GND PSU Name 0V_DIG +24V_DIG Description Microprocessor ground return +24 volt digital power supply (referred to 0V_DIG only) for relay coil RLY101 Not used Relay drive for the output relay RLY101 (LOW = output relay ON) Not used Open collector thermal fault signal (LOW = FAULT) Open collector short circuit fault signal (LOW = FAULT) Open collector DC fault signal (LOW = FAULT) Open collector overall fault signal (LOW = FAULT) Not used

3 4

I/P

MUTE OUT_RLY

5 6 7 8 9 10

O/P O/P O/P O/P

THERMPR OT VIPROT DCPROT FAULT

Sheet 2
Port INPUT connects the input of the amplifier, referred to 0V_SIG, which is the precision signal ground reference. Zener diodes DZ202 and DZ203 limit the input signal amplitude to approximately 5.3Vpk. This is to prevent damage to the input of opamp IC200, due to a leaky source signal or electrostatic discharge. R223, R228 and C210 form a passive 1st order low pass filter with a ­ 3dB corner frequency of roughly 330kHz to prevent ultrasonic signals from entering the circuit and possibly causing damage. The main amplifier circuit is a `classic' current feedback design. IC200A is configured as a non-inverting amplifier with a gain of 2. Its purpose is to provide current outputs (via its power supply pins) and a current input (via its output pin). This forms the voltage to current (transimpedance) conversion and phase splitting necessary to drive the voltage gain stage. The `current feedback' occurs because when IC200 drives its 44 load to ground, the power supply pin currents are half-wave rectified versions of the drive current of the amplifier. This causes voltage gain, which is buffered and passed on to the outputs. The feedback from the output to pin 1 of IC200 acts to reduce the gain of the amplifier; when this current is roughly equal to the current required to drive the input signal into 44, equilibrium is reached and the closed loop gain is defined. The output stage provides the vast majority of the current required to drive the 44 signals to ground. The op-amp only provides a very small error current sufficient to give the required voltage magnification. Transistors TR204 and TR203 are wired as cascodes (common base amplifiers). Their purpose is to provide IC200 with ±15V power supply rails, whilst allowing IC200's power supply pin currents to pass through them to the NPN and PNP current mirrors. The resistor, zener diode and capacitor circuits on the bases of TR204 and TR203 are to provide a controlled ramp up during power on, a stable power supply voltage and good local HF decoupling.

Sheet 1
The input to the amplifier is connected via SK103. The 2 phono sockets are connected in parallel to allow `daisychaining' of amplifier modules. R104 provides a DC leakage path to the chassis (i.e. mains power earth) to prevent small transformer leakage currents causing the electrical 0V of the amplifier to rise significantly above mains earth potential. C104 provides an EMC coupling between the local input ground and the chassis to reduce common mode RF noise. Star point SP101 connects the differently named electrical 0V nets at a single point. This is to ensure the correct wiring topology of the ground connections on the printed circuit board. SP101 provides a good common ground reference point when making voltage measurements on the PCB. Note that 0V_DIG is not connected to SP101, as this is the microprocessor ground. Relay RLY101 connects the output of the amplifier to the load via socket SK105. L101 and R103 form part of a `Zobel' network to decouple the load at high frequencies to ensure amplifier stability into capacitive loads. Note that signals 6 through 9 are open collector outputs, active low, referred to 0V_DIG with no pull-up resistors. This is because they are wire OR'd on the microprocessor PCB (L925), where the pull-up resistors to +5V digital are located.

Transistors TR200, TR201 and TR202 form a PNP Wilson current mirror. Likewise TR205, TR207 and TR206 form an NPN Wilson current mirror. The outputs of these two current mirrors are connected together via the bias network around TR212. The two current mirrors combine to provide a very high-gain current to voltage (transresistance) gain stage, which provides all the voltage gain of the amplifier (roughly 80dB at low frequency). C205, C207, R221 and R222 provide the loop compensation for the amplifier. They combine to produce an open-loop pole at roughly 10kHz and a corresponding open-loop zero around 500kHz. This allows for good time domain performance and clean square wave reproduction. The amplifier is designed to be critically damped. There should be no ringing or overshoot apparent on the output signal when a (small) step function is applied to the input. Diodes D200 and D202 act to limit the current through TR202 and TR206 in the event of a fault condition. When the input current exceeds 14mA the diodes conduct and the transresistance stage becomes a constant current source, killing the open loop gain and preventing damage to the transistors. Resistors R219 and R220 decouple the supplies for the amplifier gain stages from the main power rails. This is to permit the bootstrap circuit to modulate these supplies, increasing efficiency. The bootstrap will be described in more detail later. TR212 provides a 4.7V bias voltage to allow the following pre-driver stage to operate in class `A'. It also acts as a VBE multiplier for TR209 and TR214 to maintain an approximately constant current as the ambient temperature inside the box changes. TR209 and TR214 form a class `A' pre-driver emitter follower stage to boost the current gain and isolate the transresistance stage from the output transistors. This is important to keep the loop gain of the amplifier high and thus minimise distortion. TR208 and TR213 act as a current limit (roughly 30mA) to prevent the destruction of TR209 and TR214 in a fault condition. R247, R248, R249 and R250 are to loosely decouple the emitters of TR209 and TR214 from the output stage. This is very important. The output devices (Sanken power Darlingtons) have inbuilt temperature compensating diodes which control the bias voltage to their bases. Each output device has a 150 resistor so that the inbuilt diodes can accurately control quiescent VBE and hence collector current as the output power and device temperature varies. Preset potentiometer RV200 adjusts the quiescent current. NB: Ensure that the amplifier has fully warmed up before adjusting the quiescent current. D201 protects the output devices from destruction in the event of the preset potentiometer going open circuit. PL200 allows the test engineer to measure the bias voltage (and thus collector current). C217, C218, C220 and C221 provide local HF stability around the output transistors to prevent parasitic oscillation. D204 and D205 are catch diodes to reduce the effects of induced back-EMF in the loudspeaker load. R254 and C223 form part of the `Zobel' network that ensures the amplifier sees a constant load of roughly 4.7 at very high frequencies. This helps to improve stability and reduce HF output noise. C208 and C209 provide local high frequency decoupling for the output devices.

IC200B forms the DC integrating servo. Its purpose is to remove residual DC errors due to slight device mismatch and component tolerances. It is configured as an inverting integrator with a time constant of 0.47 seconds. Any positive DC offset at the output of the amplifier will cause the output of the op-amp to go negative, increasing the current in the negative supply pin and thus `pulling' the output down to ground (and vice versa). D203 protects the inverting input of IC200B in a fault condition. The bootstrap circuit consists of C213, C214, R241, R242, R219 and R220. The purpose of the bootstrap is to allow the output voltage swing to modulate the power supply rails of the input and voltage gain stages. This allows this circuit's power supply voltage to exceed the main power rails connected to the output devices, allowing the driver stage to fully drive the output and thus give the best thermal efficiency. The `bottom' of R219 sees a peak-to-peak voltage swing of approximately 15 volts at full output power (i.e. it goes 7.5 volts above the rail at the peak of the cycle). The `top' of R220 should see the same voltage swing.

Sheet 3
This sheet contains the protection circuits and interface to the microprocessor signals. TR309, TR305 and their associated components form the instantaneous load protection circuit for the output transistors. They sense the voltage across the 0.22 emitter resistors (hence emitter current) and the collector-emitter voltage, cutting off the base drive to the output transistors when the collector current or device power dissipation exceeds a preset limit. The protection circuit is designed to allow large (unrestricted) currents into loads of 3 and above but limit the current into a short circuit or very low impedance load. C318, C319, R335 and R336 form a 2.2ms time constant, which will allow larger transients of current delivery for a few milliseconds, to ensure that the amplifier has a sufficiently large transient capability to drive `difficult' loudspeaker loads with a music signal. TR311 also turns on when the protection circuit activates. This switches on optocoupler IC300B causing a fault signal to be transmitted to the microcontroller. The microcontroller will then switch off the output relay to protect the amplifier. TR310, TR302 and their associated components form the DC offset detection circuit. A positive DC offset at the output will turn on TR310. A negative DC offset at the output will turn on TR302, thus causing TR313 to turn on. In either case optocoupler IC300A is switched on causing a fault signal to be transmitted to the microcontroller. The microcontroller will then switch off the output relay to protect the loudspeaker voice coils from overheating. Thermistor TH300 is connected to the positive supply rail, adjacent to the collector leg of one of the power output devices. This allows it to sense the collector temperature of the output device. Its impedance when cool is low, typically a few hundred ohms. In the event of a thermal overload (above 110°C), TH300 will go to a high impedance state. This will turn on TR301, which then turns on TR300, causing optocoupler IC300D to switch on, sending a fault signal to the microcontroller. The microcontroller will then switch off the output relay until such time as the unit has cooled down to an acceptable level (80°C or so). TR301 is configured with a small amount of hysterisis (positive feedback) to ensure a clean signal is transmitted to the microprocessor via IC300D. Optocoupler IC300C is connected in series with the 3 optocouplers mentioned above, producing an overall fault signal. This is so that the microcontroller can determine in which module the fault has occurred, permitting selective control of the output relay for each module in the amplifier.

L924 Amplifier Module Parts List Issue 1.1
Designator Part
BR300 BR301 C103 C104 C200 C201 C202 C203 C204 C205 C207 C208 C209 C210 C212 C213 C214 C215 C216 C217 C218 C220 C221 C223 C225 C300 C301 C305 C306 C318 C319 C320 C321 C322 C323 D101 D200 D201 D202 D203 D204 D205 D300 D301 D303 D307 D308 D309 DZ200 DZ201 DZ202 DZ203 IC200 IC300 L101 PL100 PL200 R103 R104 R207 R208 R210 3BGBU8D 3BGBU8D 2C410 2C210 2C410 2C410 2C410 2N710 2N710 2D110W2 2D110W2 2C410A 2C410A 2D147W 2K447 2N710B 2N710B 2N610 2N610 2C047B 2C047B 2C047B 2C047B 2K347 2N610 2C410 2N710 2C410 2C410 2N710 2N710 2V710 2V710 2P910AM 2P910AM 3AS16W 3AS16W 3AS16W 3AS16W 3AV99W 3B4003 3B4003 3AS16W 3CW315V 3AS16W 3AS16W 3CW322V 3CW322V 3CW315V 3CW315V 3CW34V7 3CW34V7 5B072D 5T3Q66 7D002C 8K6201 8K6201 1H822 1A110 1A110 1A110 1A327

Description
Diode Bridge Rectifier GBU8D Plastic Package 8A 200V Diode Bridge Rectifier GBU8D Plastic Package 8A 200V Capacitor SM 1206 X7R Ceramic 50V 10% 100N Capacitor SM 1206 NPO Ceramic 50V 5% 1N0 Capacitor SM 1206 X7R Ceramic 50V 10% 100N Capacitor SM 1206 X7R Ceramic 50V 10% 100N Capacitor SM 1206 X7R Ceramic 50V 10% 100N Capacitor Radial Electrolytic Dia 5mm Pitch 5mm 100UF 25V Capacitor Radial Electrolytic Dia 5mm Pitch 5mm 100UF 25V Capacitor Boxed Polyprop 5mm Pitch 250V 5% 100P Capacitor Boxed Polyprop 5mm Pitch 250V 5% 100P Capacitor SM 1812 X7R Ceramic 500V 10% 100N Capacitor SM 1812 X7R Ceramic 500V 10% 100N Capacitor Boxed Polyprop 5mm Pitch 100V 5% 470P Capacitor Boxed Polyester 5mm Pitch 10% 63V 470N Capacitor Radial Electrolytic Dia 10mm Pitch 5mm 100UF 100V Capacitor Radial Electrolytic Dia 10mm Pitch 5mm 100UF 100V Capacitor Radial Electrolytic Dia 5mm Pitch 5mm 10UF 50V Capacitor Radial Electrolytic Dia 5mm Pitch 5mm 10UF 50V Capacitor SM 0805 NPO Ceramic 200V 5% 47PF Capacitor SM 0805 NPO Ceramic 200V 5% 47PF Capacitor SM 0805 NPO Ceramic 200V 5% 47PF Capacitor SM 0805 NPO Ceramic 200V 5% 47PF Capacitor Boxed Polyester 5mm Pitch 10% 63V 47N Capacitor Radial Electrolytic Dia 5mm Pitch 5mm 10UF 50V Capacitor SM 1206 X7R Ceramic 50V 10% 100N Capacitor Radial Electrolytic Dia 5mm Pitch 5mm 100UF 25V Capacitor SM 1206 X7R Ceramic 50V 10% 100N Capacitor SM 1206 X7R Ceramic 50V 10% 100N Capacitor Radial Electrolytic Dia 5mm Pitch 5mm 100UF 25V Capacitor Radial Electrolytic Dia 5mm Pitch 5mm 100UF 25V Capacitor Non-Polar Radial Electrolytic 100UF 16V Capacitor Non-Polar Radial Electrolytic 100UF 16V Capacitor Radial Electrolytic Dia 40mm PCB Mount 10000uF 71V Capacitor Radial Electrolytic Dia 40mm PCB Mount 10000uF 71V Diode Surface Mount Small Signal BAS16W SOT-23 Package Diode Surface Mount Small Signal BAS16W SOT-23 Package Diode Surface Mount Small Signal BAS16W SOT-23 Package Diode Surface Mount Small Signal BAS16W SOT-23 Package Diode Dual Surface Mount Small Signal BAV99 SOT-23 Package Diode 1N4003 DO-41 Package Diode 1N4003 DO-41 Package Diode Surface Mount Small Signal BAS16W SOT-23 Package Zener Diode 0.25W Surface Mount BZX84C15V SOT-23 Package Diode Surface Mount Small Signal BAS16W SOT-23 Package Diode Surface Mount Small Signal BAS16W SOT-23 Package

Zener Diode 0.25W Surface Mount BZX84C15V SOT-23 Package Zener Diode 0.25W Surface Mount BZX84C15V SOT-23 Package Zener Diode 0.25W Surface Mount BZX84C4V7 SOT-23 Package Zener Diode 0.25W Surface Mount BZX84C4V7 SOT-23 Package Opamp TL072CD SO-8 Package Opto Isolator Quad PC3Q66Q Inductor AC 2u2 SELF BONDED CON SINGLE ROW HDR 0.1IN VERTICAL 2WAY CON SINGLE ROW HDR 0.1IN VERTICAL 2WAY Resistor Metal Film 0.25W 1% 2R2 Resistor 1206 Surface Mount 0.25W 1% 100R Resistor 1206 Surface Mount 0.25W 1% 100R Resistor 1206 Surface Mount 0.25W 1% 100R Resistor 1206 Surface Mount 0.25W 1% 27K

L924 Amplifier Module Parts List Issue 1.1
Designator Part
R211 R212 R213 R214 R216 R217 R218 R219 R220 R221 R222 R223 R224 R225 R226 R227 R228 R229 R230 R231 R232 R233 R234 R235 R236 R237 R238 R239 R240 R241 R242 R245 R246 R247 R248 R249 R250 R254 R255 R257 R300 R301 R302 R303 R304 R305 R306 R307 R310 R311 R314 R315 R316 R320 R321 R332 R333 R334 R335 R336 R337 R338 1A327 1A327 1A327 1A047 1A047 1A047 1A047 1H122 1H122 1A233 1A233 1A210 1A210 1A210 1A210 1A210 1A322 1H022 1H022 1A247 1H156 1H156 1H168 1H168 1H239 1H239 1H239 1H239 1A510 1C210 1C210 1A022 1A022 1A115 1A115 1A115 1A115 1D847 1A268 1A210 1A110 1A110 1A110 1A322 1A127 1A310 1A310 1A339 1A110 1A110 1A110 1A110 1A322 1A322 1A322 1A322 1A322 1A247 1A022 1A022 1A210 1A133

Description
Resistor 1206 Surface Mount 0.25W 1% 27K Resistor 1206 Surface Mount 0.25W 1% 27K Resistor 1206 Surface Mount 0.25W 1% 27K Resistor 1206 Surface Mount 0.25W 1% 47R Resistor 1206 Surface Mount 0.25W 1% 47R Resistor 1206 Surface Mount 0.25W 1% 47R Resistor 1206 Surface Mount 0.25W 1% 47R Resistor Metal Film 0.25W 1% 220R Resistor Metal Film 0.25W 1% 220R Resistor 1206 Surface Mount 0.25W 1% 3K3 Resistor 1206 Surface Mount 0.25W 1% 3K3 Resistor 1206 Surface Mount 0.25W 1% 1K0 Resistor 1206 Surface Mount 0.25W 1% 1K0 Resistor 1206 Surface Mount 0.25W 1% 1K0 Resistor 1206 Surface Mount 0.25W 1% 1K0 Resistor 1206 Surface Mount 0.25W 1% 1K0 Resistor 1206 Surface Mount 0.25W 1% 22K Resistor Metal Film 0.25W 1% 22R Resistor Metal Film 0.25W 1% 22R Resistor 1206 Surface Mount 0.25W 1% 4K7 Resistor Metal Film 0.25W 1% 560R Resistor Metal Film 0.25W 1% 560R Resistor Metal Film 0.25W 1% 680R Resistor Metal Film 0.25W 1% 680R Resistor Metal Film 0.25W 1% 3K9 Resistor Metal Film 0.25W 1% 3K9 Resistor Metal Film 0.25W 1% 3K9 Resistor Metal Film 0.25W 1% 3K9 Resistor 1206 Surface Mount 0.25W 1% 1M0 Resistor Carbon Film 2W 5% 1K0 Resistor Carbon Film 2W 5% 1K0 Resistor 1206 Surface Mount 0.25W 1% 22R Resistor 1206 Surface Mount 0.25W 1% 22R Resistor 1206 Surface Mount 0.25W 1% 150R Resistor 1206 Surface Mount 0.25W 1% 150R Resistor 1206 Surface Mount 0.25W 1% 150R Resistor 1206 Surface Mount 0.25W 1% 150R Resistor Carbon Film 0W5 5% 4R7 Resistor 1206 Surface Mount 0.25W 1% 6K8 Resistor 1206 Surface Mount 0.25W 1% 1K0 Resistor 1206 Surface Mount 0.25W 1% 100R Resistor 1206 Surface Mount 0.25W 1% 100R Resistor 1206 Surface Mount 0.25W 1% 100R Resistor 1206 Surface Mount 0.25W 1% 22K Resistor 1206 Surface Mount 0.25W 1% 270R Resistor 1206 Surface Mount 0.25W 1% 10K Resistor 1206 Surface Mount 0.25W 1% 10K Resistor 1206 Surface Mount 0.25W 1% 39K Resistor 1206 Surface Mount 0.25W 1% 100R Resistor 1206 Surface Mount 0.25W 1% 100R Resistor 1206 Surface Mount 0.25W 1% 100R Resistor 1206 Surface Mount 0.25W 1% 100R Resistor 1206 Surface Mount 0.25W 1% 22K Resistor 1206 Surface Mount 0.25W 1% 22K Resistor 1206 Surface Mount 0.25W 1% 22K Resistor 1206 Surface Mount 0.25W 1% 22K Resistor 1206 Surface Mount 0.25W 1% 22K Resistor 1206 Surface Mount 0.25W 1% 4K7 Resistor 1206 Surface Mount 0.25W 1% 22R Resistor 1206 Surface Mount 0.25W 1% 22R Resistor 1206 Surface Mount 0.25W 1% 1K0 Resistor 1206 Surface Mount 0.25W 1% 330R

L924 Amplifier Module Parts List Issue 1.1
Designator Part
R339 R340 R341 R342 R343 RLY101 RV200 SK103 SK104 SK105 SK300 SK301 TH300 TR200 TR201 TR202 TR203 TR204 TR205 TR206 TR207 TR208 TR209 TR210 TR211 TR212 TR213 TR214 TR215 TR216 TR300 TR301 TR302 TR305 TR309 TR310 TR311 TR312 TR313 Z100 Z101 Z102 Z103 Z104 Z105 Z106 Z107 Z108 Z109 Z110 1A133 1A310 1A310 1A412 1A410 A220 6F110V 8D226 8K2810 8D421 8K2302 8K2302 1T007 4AFMMT597 4AFMMT597 4B1740 4AFMMT597 4AFMMT497 4AFMMT497 4B4548 4AFMMT497 4AFMMT497 4B4548 4CSAP15N 4CSAP15N 4AFMMT497 4AFMMT597 4B1740 4CSAP15P 4CSAP15P 4AFMMT497 4AFMMT597 4AFMMT597 4AFMMT597 4AFMMT497 4AFMMT497 4AFMMT497 4AFMMT497 4AFMMT497 L924PB E107AY E915HK HF4V09B HF4V09B HF4V09B E950MC HB3B12A HB3B12A HB3B12A HB3B12A

Description
Resistor 1206 Surface Mount 0.25W 1% 330R Resistor 1206 Surface Mount 0.25W 1% 10K Resistor 1206 Surface Mount 0.25W 1% 10K Resistor 1206 Surface Mount 0.25W 1% 120K Resistor 1206 Surface Mount 0.25W 1% 100K Relay 1P2T 24V Preset Vertical Mount 100R linear Phono socket 2 way vertical gold CON HORIZ PCB SKT 10WAY Connector 4mm 2 way horizontal CON MINIFIT HCS V 2WAY CON MINIFIT HCS V 2WAY Thermistor PTC SM 110 degrees C Transistor FMMT597 SOT23 Package Transistor FMMT597 SOT23 Package Transistor 2SA1740 SOT-89 Package Transistor FMMT597 SOT23 Package Transistor FMMT497 SOT23 Package Transistor FMMT497 SOT23 Package Transistor 2SC4548 SOT-89 Transistor FMMT497 SOT23 Package Transistor FMMT497 SOT23 Package Transistor 2SC4548 SOT-89 Transistor SAP15NY Transistor SAP15NY Transistor FMMT497 SOT23 Package Transistor FMMT597 SOT23 Package Transistor 2SA1740 SOT-89 Package Transistor SAP15PY Transistor SAP15PY Transistor FMMT497 SOT23 Package Transistor FMMT597 SOT23 Package Transistor FMMT597 SOT23 Package Transistor FMMT597 SOT23 Package Transistor FMMT497 SOT23 Package Transistor FMMT497 SOT23 Package Transistor FMMT497 SOT23 Package Transistor FMMT497 SOT23 Package Transistor FMMT497 SOT23 Package BLANK PCB 7 CHANNEL AMP MODULE ASSEMBLY OF REAR PANEL MODULE AND SILK SCREEN Finished Heatsink for single channel amp module SCREW SELF-TAPPING-SEMS NO.4 X 9MM PAN TORX-SLOT STEEL ZINC-PLATE BLK SCREW SELF-TAPPING-SEMS NO.4 X 9MM PAN TORX-SLOT STEEL ZINC-PLATE BLK SCREW SELF-TAPPING-SEMS NO.4 X 9MM PAN TORX-SLOT STEEL ZINC-PLATE BLK INSULATOR P7 TRANSISTOR INSULATING PAD SCREW TAPTITE HEXAGON WASHER FACE M3X12MM SCREW TAPTITE HEXAGON WASHER FACE M3X12MM SCREW TAPTITE HEXAGON WASHER FACE M3X12MM SCREW TAPTITE HEXAGON WASHER FACE M3X12MM

To microprocessor PCB
+24V_DIG SK104 10WAY-H-0.1-F TP102 1 Microprocessor GND 2 Microprocessor +24V 3 MUTE MUTE not used 4 OUT RLY Output relay control 5 Not used 6 THERMPROT Thermal protection 7 VIPROT SOA protection 8 DCPROT DC offset protection 9 FAULT Overall fault signal 10 Not used L924C3 L924C3_1.1.sch EMITTER1 EMITTER2 OUTPUT EMITTER1 EMITTER2 OUTPUT VIPROT DC THERM FAULT BASE1 BASE2 VIPROT DCPROT THERMPROT FAULT

NB: Nets +24V_DIG and 0V_DIG are isolated from amplifier circuit
+24V_DIG TP103 TP104 TP105 TP106 TP107 TP108 TP109 RLY101B RLY G2R-1E-24DC 16A SPDT 0V_DIG C103 100N SM D101 BAS16W SM

NB: Signals THERMPROT, VIPROT, DCPROT and FAULT are open collector outputs, active low, referenced to 0V_DIG with no pull up resistors

Electrical ground star point
0V_SIG

Inputs
SK103 PHONO2G 1 L924C2 L924C2_1.1.sch INPUT PL100 1 2 2WVERTJUMPER R104 100R SM BASE1 BASE2 NFB

OUT RLY SP101 STAR_8 0V_HF 0V_ZOB 0V_PSU 0V_LS

F EMC
C104 1N0 SM

TP100

N

Amplifier circuit
TP101 0V_SIG

Protection and supplies
R103 RLY101A RLY G2R-1E-24DC 16A SPDT TP110 2R2 MF TP111 SK105 L101 2U2 AIR CORED

NB: Feedback around relay not fitted

4MM 2W HOR TP112

0V_LS

Z100 PCB L924PB Z101 SUB PANEL E107AY

Z102 HEATSINK E915HK Z103 SUB PANEL SCREW HF4V09B

Z106 TRANSISTOR INSULATOR E950MC Z104 SUB PANEL SCREW HF4V09B

Z107 M3 TAPTITE HB3B12A Z105 SUB PANEL SCREW HF4V09B

Z108 M3 TAPTITE HB3B12A

Z109 M3 TAPTITE HB3B12A

Z110 M3 TAPTITE HB3B12A DRAWING TITLE

P7 Amplifier Module
Filename: Notes: L924C1_1.1.sch

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

02_E055
ECO No. Contact Engineer: Jonny Reckless Contact Tel: (01223) 203200

JR
INITIALS Printed:

4/3/2002
DATE 7-Mar-2002

FIXED DC FAULT AT POWER ON SEQUENCE BY FEEDBACK
DESCRIPTION OF CHANGE

1.1
ISSUE

Sheet

1

of

3

DRAWING NO.

L924CT

+55V R219 220R MF

R210 27K SM

R211 27K SM TR200 FMMT597

R214 47R SM

D200 BAS16W SM

R216 47R SM C208 100N X7R 1812 500V

PNP current mirror
TR201 FMMT597

+
C203 100U EL DZ200 15V 350MW SM TR202 TR PNP 2SA1740

0V_HF C212 470N PE IC200B TL072CD 7 5 TP203 R231 4K7 SM TR204 FMMT497 0V_SIG C200 100N SM 0V_SIG TP200 IC200A TL072CD 1 2 4 R228 22K SM C210 470P PPW TP201 R229 22R MF R230 22R MF TP202 R232 560R MF R233 R223 1K0 SM DZ202 4V7 350MW SM DZ203 4V7 350MW SM 560R MF R236 NF R237 NF R238 NF R239 NF 0V_SIG C201 100N SM R234 6

R221 3K3 SM

C205

Pre driver
100P/250V TR209 TR NPN 2SC4548 R207 100R SM R245 22R SM C217 47P/200V R247 150R SM R224 1K0 SM TR210 SAP15N C218 47P/200V R248 150R SM EMITTER1 R225 1K0 SM TP204 BIAS PL200 1 2 TR211 SAP15N

Output stage
BASE1

R240 1M0 SM

TR208 FMMT497

D203 BAV99W

Integrating DC servo
+ C213 100U EL 100V
RV200 100R PSET

Measure Iq
R241 1K CF 2W C215 10U EL

680R MF R235 680R MF

+

D201 BAS16W SM

+ C216 10U EL

TP205

D204 1N4003F

Input Filter
3 8

Bootstrap
OUTPUT

INPUT

NFB R236 THRU R239 NOT FITTED R242 1K CF 2W

Trim output stage Iq
D205 1N4003F R254 4R7 W2 CF

+ C214 100U EL 100V

C223 47N PE 0V_ZOB

V to I converter
R255 6K8 SM TR212 FMMT497 R226 1K0 SM R227 1K0 SM

+
0V_HF C204 100U EL DZ201 15V 350MW SM TR203 FMMT597 R213 27K SM C202 100N SM 0V_SIG

+ C225 10U EL

Pre driver
R246 22R SM R208 100R SM

EMITTER2 R249 150R SM TR215 SAP15P R250 150R SM C221 47P/200V TR216 SAP15P

R257 1K SM

C220 47P/200V

R212 27K SM

Pre driver bias

TR213 FMMT597

BASE2 TR214 TR PNP 2SA1740

Output stage

R222 3K3 SM

C207 100P/250V 0V_HF

TR206 TR NPN 2SC4548

C209 100N X7R 1812 500V TR205 FMMT497 TR207 FMMT497

NPN current mirror
R217 47R SM D202 BAS16W SM R218 47R SM

R220 220R MF

-55V

DRAWING TITLE

P7 Amplifier Module
Filename: Notes: L924C2_1.1.sch

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

02_E055
ECO No. Contact Engineer: Jonny Reckless Contact Tel: (01223) 203200

JR
INITIALS Printed:

4/3/2002
DATE 7-Mar-2002

FIXED DC FAULT AT POWER ON SEQUENCE BY FEEDBACK
DESCRIPTION OF CHANGE

1.1
ISSUE

Sheet

2

of

3

DRAWING NO.

L924CT

+55V
IC300C OPTO-PC3Q66-QUAD-SM

FAULT

IC300A D308 22V 350MW SM OPTO-PC3Q66-QUAD-SM

DC

IC300B OPTO-PC3Q66-QUAD-SM VIPROT

TH300 PTH 110DEG SM R304 270R SM

IC300D

THERM

C300 100N SM R321 22K SM

OPTO-PC3Q66-QUAD-SM

Instant SOA limiting
BASE1
D300 BAS16W SM R320 22K SM

0V_DIG

0V_DIG

+ C301 100U EL

D301 15V 350MW SM

R343 100K SM TR301 FMMT597 R342 120K SM R305 10K SM R307 39K SM R306 10K SM

R303 22K SM

0V_DIG

R337 1K SM

R310 R340 10K SM R338 330R SM R302 100R SM TR309 FMMT497 D303 BAS16W SM 100R SM

TR311 FMMT497

TR300 FMMT497

EMITTER1

0V_HF

+ C318 100U EL

Over temperature sensing
C305 100N SM TR310 FMMT497

R300 100R SM

R335 22R SM

DC offset detection
OUTPUT
R316 R301 100R SM R336 22R SM 22K SM C320 100U NP C306 100N SM TR305 FMMT597 R332 22K SM R333 22K SM C321 100U NP R334 4K7 SM TR302 FMMT597 TP300

+ C319 100U EL
R311

0V_HF 0V_HF

EMITTER2

R339 330R SM

100R SM R341 10K SM

D307 BAS16W SM

BASE2

Power supplies
+55V 1

Instant SOA limiting

TR312 FMMT497

TR313 FMMT497 SK300 MOLEXPWR2WAY_R/A

BR300 BRGBU8D

TP302

+

AC from transformer
D309 22V 350MW SM R314 100R SM R315 100R SM

1 2
TP304

3

~

~

2

+ C322 C AM 71V 10000U

TP305

1

4

-

-55V

AC from transformer

SK301 MOLEXPWR2WAY_R/A 1 TP306 2

BR301 BRGBU8D

+

0V_PSU + C323 C AM 71V 10000U

3

~

~

2

TP303

4

-

-55V
TP307

DRAWING TITLE

P7 Amplifier Module
Filename: Notes: L924C3_1.1.sch

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

02_E055
ECO No. Contact Engineer: Jonny Reckless Contact Tel: (01223) 203200

JR
INITIALS Printed:

4/3/2002
DATE 7-Mar-2002

FIXED DC FAULT AT POWER ON SEQUENCE BY FEEDBACK
DESCRIPTION OF CHANGE

1.1
ISSUE

Sheet

3

of

3

DRAWING NO.

L924CT

Controller Board L925
Contents

!

Circuit description

!

Component overlay

!

Parts list

!

Circuit diagrams

P7 Controller Circuit Description
The Amp controller PCB Panel consists of 6 PCBs. ! ! ! ! ! Controller PCB Display PCB Connector PCB Mains Switch PCB 2x Wire Clamp PCBs

power relays ensures that relay RLY101 never switches high voltages and its contacts remain clean.

Voltage selection for 115/230V operation
The control PCB provides a means of configuring the unit for 115V or 230V operation. This is achieved by having 2 connectors marked with the appropriate voltage for each of the units 3 transformers (1 auxiliary transformer which powers the control PCB and 2 large toroids each of which powers 3 ½ amplifier modules). The connectors SK101, SK102 for the aux TX and SK103, SK104 for the Right hand power toroid and SK105, SK106 for the left hand power torroid are configured to place the two primary windings of each transformer in parallel for 115V operation and in series for 230V operation. The arrangement of fuses (6 in total which are all fitted) ensures that each winding has a series fuse when configured in parallel for 115V operation and 1 of each pair of fuses is used to fuse the series configured windings when set for 230V operation. In this way there are 2 parallel fuses for each transformer when set for 115V (to allow twice the current as required). The fuses are time delay types. C121 is X rated and provides suppression for rectifier switching transients for EMC conducted noise compliance. RC100 is a series RC network to prolong relay life.

Overview
The controller PCB contains the microprocessor and most of the circuitry for controlling the P7 amplifier. The display PCB provides the LEDs and resistors for the simple 7 LED display for the front panel of the unit. The mains switch PCB provides a means of supporting the front panel mounted mains switch. The connector PCB fits on the base of the chassis near the rear panel and provides a means of connecting the 7 amplifier modules to a connector which is then linked to the controller PCB. The connector PCB also provides a means of mounting the rear panel mounted trigger input connector and connecting its signals to the mains controller PCB. The cable clamp PCBs are used to hold the transformer power cables neatly to the side of the chassis base.

The controller PCB +5V supply (for logic)
The controller PCB provides the following functionality ! ! ! ! ! ! ! ! ! ! ! ! ! ! Mains power distribution, switching and soft-start Voltage selection for 115/230V operation. +5V (for logic) supplies +22V (for relay and fan) supplies Variable speed fan drive Relay control for soft starts and sequenced power up/ power down for switch on, switch off and fault conditions. Heatsink temperature measurement for fan speed control Transformer Thermal trip monitoring Mains supply monitoring for output muting Soft start resistor monitoring to prevent soft start resistor overdissipation Amplifier module fault status monitoring for module over-temperature, module DC offset, module VI limit Output muting relays drive circuit Amplifier status display drive circuitry via the front panel mounted LEDs. Watch-dog failsafe mechanism which activates in the case of microprocessor failure The auxiliary transformer has 2 secondary windings. These are rectified by full wave rectifiers to form the DC supplies. The +5V supply is rectified by D101, D102, D105, D106 and smoothed by C102. The supply is then regulated by the 3 terminal 5V regulator REG100. The supply is designed to provide 9.5V DC to th input of the regulator when fed with a nominal 230V. This allows 8V at the input to the regulator (so that it remains within regulation) when fed from 195V mains supply. The regulator is fitted with a heatsink. C103 is provided to eliminate input transients. C107 ensures regulator stability.

+22V supply (for relay and fan)
The +22V supply is formed in a similar manner by D103, D104, D107, D108 and C101. The supply voltage is chosen to give 22V when driven from a mains voltage of 230V. This gives around 24V when the mains supply is at its maximum value (265V). This is due to the relays having a maximum specified input voltage of 24V.

Mains power distribution, switching and soft-start
The mains input supply is connected directly to the control PCB via SK100. The mains supply is routed through the power relay RLY100 and through the 3 parallel resistors R100, R101, R102. These form a high power rated 50Ohm resistor that is used to limit the inrush current into the 2 large power toroids. These toroids are mounted beneath the transformer tray at the front of the unit. The 50-Ohm series resistor limits the inrush current to 5A and is allowed to remain in circuit for a few hundred milliseconds after power on. After the power amplifier module electrolytic capacitors have charged to full supply voltage the current through the resistor falls to a low value (which is sensed by the circuitry around IC105 as described below) and the soft start resistor is then switched out of circuit by relay RLY101. This arrangement of

Variable fan speed drive
The fan for the amplifier is required to be very quiet. This is achieved by having the fan speed proportional to temperature. The temperature is measured by the microprocessor (as described below) and when the temperature exceeds a programmed threshold then the fan is switched on at its lowest speed (approx 7V). As the temperature of the unit increases the fan speed is increased until it is operating at full speed (12V). This is achieved by having the microprocessor output a PWM 5V pk to pk square wave on line PWM_OUT. The square wave is filtered by R112, C108 to form a DC level. The amplitude of the DC level is thus proportional to the duty cycle that is under microprocessor control. The filtered DC signal is then amplified by the simple 4 transistor amplifier formed around TR100, TR113, TR114 and TR115. The gain of the amplifier is set by R117, R118 to around 6. This ensures

that the PWM_OUT signal duty cycle can move the output of the amplifier over the required range. C104, C113 provide suppression for EMC and C112 provides amplifier loop compensation. The supply to the fan is fused by F101 this fuse limits current in the event of the fan stalling. If the fuse blows the watchdog timer cct immediately switches off the power relays to ensure failsafe condition.

pulled to 5V through R131. In the event of 1 (or both) transformer trips going open circuit then line TX_OVTEMP goes high and the microprocessor is then able to power the amplifier down as required.

Mains supply monitoring for output muting
In order to prevent thumps through the loudspeaker when the amplifier is switched off it is necessary to detect the removal of the mains supply so that the amplifier modules can be muted. This is affected by the circuitry around TR101 and the microprocessor. The AC supply for the 22V rail is sensed by R109. At the positive peak of the mains supply TR101 is turned on and saturates thereby discharging C109. In the event of the AC supply disappearing then C109 will not be discharged and will instead charge to 5V through R132. The time constant R132 . C109 = 47mS sets the time taken for line PWROK* to go high. So if the mains supply disappears for around 5 capacitor charge cycles then PWROK* will notify the microprocessor which will then mute the amplifier outputs.

Relay control
The power relay and soft-start relay (RLY100, RLY101) respectively are driven by microprocessor signals MPOWER and MSOFT_ST*. Transistors TR108, TR111 buffer the microprocessor outputs. Diodes D115 and D119 prevent damage to the collectors of the transistors by the inductance of the relay coils at coil switch off. The power for the relay coils (+22V_SW) is provided through TR116. This transistor is off (hence relays off) when the watchdog circuit detects no microprocessor activity (as described below) or the fan fuse F101 is blown (as described above).

Heatsink temperature measurement Soft start resistor monitoring
The microprocessor monitors the temperature of the heatsink using the circuitry around TR112. Capacitor C114 is alternately charged through fixed resistor R122 (2K2) and thermistor TH100. The time taken to charge the capacitor is measured by the microprocessor. The ratio of the time taken to charge the capacitor through the 2K2 fixed resistor compared with the time taken to charge the capacitor through the thermistor allows the microprocessor to calculate the resistance of the thermistor. The software is then able to establish the temperature of the thermistor from its resistance. Three microprocessor lines are involved in this measurement. TREF, TTEMP, C_DISCH. A measurement cycle proceeds as follows. C_DISCH goes high to discharge C114. After a delay to ensure C114 is fully discharged C_DISCH then goes Low and TREF is set as an output and goes high. TTEMP is set as an input. This allows C114 to charge through R122. The time taken for C114 to charge to the input high threshold of the micro is measured by timing through input TTEMP. When the threshold is reached, C_DISCH is again taken high to discharge the capacitor. After a delay to ensure C114 is fully discharged C_DISCH then goes Low and TTEMP is set as an output and goes high. TREF is set as an input. This allows C114 to charge through TH100. The time taken for C114 to charge to the input high threshold of the micro is measured by timing through input TREF. When the threshold is reached, C_DISCH is again taken high to discharge the capacitor. This cycle is repeated continuously and the ratio of capacitor charge times allows the ratio of resistance R122 to resistance TH100 to be measured. The measurement is immune to variation in value of C114, saturation voltage of TR112 and average supply voltage on the 5V rail. The variation of input voltage 1 threshold of the TREF and TTEMP inputs is not compensated for but in practice this is usually found to be minimal. The method should give a measurement accuracy of a few degrees C that is all that is needed for fan speed control. The soft start resistor is used to limit the inrush current into the large power transformers. The resistor is designed to be in-circuit only for the duration of the inrush current at switch on. The resistor must be shorted out by the relay before the amplifier is configured to deliver output current. Also in the event of a fault (e.g. a short across one of the amplifier module reservoir capacitors) then the resistor might be exposed to a situation which might cause over dissipation. This is avoided by having the microprocessor monitor the voltage across the resistor so that in the event of a fault the amplifier can be switched off before damage to the resistor occurs. The voltage across the soft-start resistor is monitored by the circuitry around IC105. When voltage is present across the soft-start resistor (only the positive half cycle is sensed) then the opto-transistor is turned on. This discharges C100. The RC time constant R104, C100 = 220mS dictates that line SSPROT* will be low until around ¼ of a second after the voltage across the soft-start resistor has fallen to zero.

Amplifier module fault status monitoring
! ! ! Module over-temperature Module DC offset Module VI limit

The amplifier modules contain circuitry that senses the above fault conditions. The fault status is indicated to the control PCB by means of open collector transistors on each module that are ON when the fault exists. The means of connecting the fault lines to the control PCB requires explanation. There are 7 amplifier modules, each of which has 3 fault lines. If these were tracked individually then this would require 21 lines to the control PCB. In order to reduce the number of lines required then the connections are changed so that the 3 fault lines from each of the are 7 modules are connected in parallel. So that e.g. the VI limit fault line is pulled low when any one of the 7 modules exhibits a VI limit fault. In order for the controller to establish which module has the fault (so that

Transformer Thermal trip monitoring
The main power transformers have thermal trips built into them. These are normally closed and go open when the trip temperature is exceeded. The trips are put in series and

it can be indicated on the front panel display) each module also provides an address line. A fault occurring on a particular module will cause both the fault line to be low and also the address line. In this way the amplifiers can be monitored by the controller through a total of 10 lines. The address lines are called: FAULTn* (where n = 1 to 7 as per amplifier module number) The fault lines are: FLT_DC* to indicate a DC offset error FLT_VI* to indicate VI limit protection FLT_TEMP* to indicate that the temperature of the output transistors has exceeded the 110C trip temperature.

that is averaged to 2.5V by the filter R114, C110. The voltage is then fed to the window comparator formed around IC104. The network R105, R106 and R107 sets the upper and low thresholds at 75% of 5V and 25% of 5V respectively. The outputs are open collector and if the filtered WATCHDOG signal exceeds the upper threshold or falls below the lower threshold then the b-e junction of TR103 is pulled low and TR116 is then turned off ­ which removes the power to the relays. The filtered WATCHDOG signal can only move outside the window if the WATCHDOG line sits high (or low) continuously. This can only occur if the microprocessor breaks or the software crashes. This protection scheme also includes the fan fuse (F101). If the fan fuse blows then TR103 gets no base current that also immediately removes the power supply to the relays.

Output muting relays
The muting relays are on the amplifier modules. The relays allow the amplifier to be disconnected from the loudspeaker load. This is required for muting switch on and switch off thumps and in the event of fault conditions. The relays are driven from the control PCB by the simple open collector transistor drive arrangement formed around TR102, TR104- TR110. The diodes D111-D118 protect the transistor collectors against over voltage spikes occurring when the inductive relay coils are switched off. The open collector transistors are driven through the 74HC259 type addressable latch. This configuration allows 24 output lines to be provided from 7 microprocessor lines. The outputs of one of the 259s (IC103) are used to drive the muting relay transistors. The remaining packages (IC101, IC102) are used to drive the display LEDs as described below. Control of the 259s is as follows. Each has 3 address bits S0, S1, S2 which allows one of 8 outputs to be selected, a DATA input which allows a 0 or a 1 to be latched to the output and a GATE input which transfers the signal on DATA to the selected (addressed) output of the package. The GATE input is also used as a chip select to select which of the 3 packages is being controlled. This allows the S and DATA inputs to be connected in parallel on multiple packages.

LED PCB
The LED PCB contains the 7 bicolour LEDs and their current limiting resistors. The LED PCB also provides a means of routing the mains switch wiring to the control PCB via the LED PCB to control PCB flexfoil cable.

Connector PCB
The connector PCB provides a means of joining the amplifier modules to the control PCB via the 22way flexfoil cable. The PCB also includes circuitry for the 12V trigger circuit. The trigger circuit is formed around SK201. The 12V trigger signal is converted to a 5V logic level compatible signal by R200, D200. C201 and C202 provide EMC suppression (since the signal is ultimately routed to the Control PCB which contains a microprocessor). R202 isolates the ground pin of the jack socket from the amplifier ground. This prevents possible ground loop problems with other hifi components connected in the system. The zener diode clamped signal is limited to 4.7V pk amplitude. This is fed to the microprocessor via line TRIG/RC5

Amplifier status display
The amplifier status is indicated via the front panel mounted LEDs. IC101, IC102 are used to directly drive the tricolour LEDs which are mounted on the LED PCB. Each channel has a single Tricolour LED. The LED has a red and green LED built in and the third colour (yellow) is produced by having both Red and Green LEDs ON at the same time. IC101 is connected to the red LEDs and IC102 is connected to the green LEDs.

Fault conditions
Fault D.C When a D.C fault is created on an amplifier all the LEDS turn red accept the module with the fault that flashes green. Fault V.I When a V.I fault is created all the LEDS turn red accept the module with the fault which flash red. Therm fault (amplifier overheating) When a therm fault is created all the LEDS stay green and the amp module with the fault flashes amber. Thermal trip (TX overheating) When a thermal trip is created all the LEDS flash amber, stating that it is a transformer problem.

Watch-dog
The watch dog circuit provides a failsafe mechanism which places the amplifier in a safe (OFF) state in the event of the microprocessor failing or crashing. The circuitry monitors the average voltage on the WATCHDOG line and if it falls outside its required voltage then it removes the power supply to the relays which has the effect of muting the amplifier outputs and removing the power to the power amplifier toroids. The line WATCHDOG is toggled by the software in the micro. Every time it completes a program loop it toggles the state of the line. This results in a 50% duty cycle signal

L925 Controller Board Parts List Issue 1.2
Designator Part
C100 C101 C102 C103 C104 C105 C106 C107 C108 C109 C110 C111 C112 C113 C114 C115 C116 C117 C118 C119 C120 C121 C200 C201 C202 D100 D101 D102 D103 D104 D105 D106 D107 D108 D109 D110 D111 D112 D113 D114 D115 D116 D117 D118 D119 D120 D200 F100 F100-1 F100-2 F101 F101-1 F101-2 F102 F102-1 F102-2 F103 F103-1 F103-2 F104 F104-1 F104-2 F105 F105-1 2N547 2N833A 2N810 2K410 2K410 2K410 2K410 2N722B 2N610 2N610 2N610 2N610 2K210 2N747 2N747 2N610 2N647 2A410 2A410 2A410 2A410 2D447 2A410 2A210 2A210 3B4003 3B4003 3B4003 3B4003 3B4003 3B4003 3B4003 3B4003 3B4003 3A4148 3A4148 3A4148 3A4148 3A4148 3A4148 3A4148 3A4148 3A4148 3A4148 3A4148 3F5711 3C04704 C11316 8S004 F022 C11316 8S004 F022 C11316 8S004 F022 C12406 8S004 F022 C12406 8S004 F022 C12406 8S004

Description
Capacitor Radial Electrolytic Dia 5mm Pitch 5mm 4U7 50V Capacitor Radial Electrolytic Dia 16mm Pitch 7.5mm 3300UF 35V Capacitor Radial Electrolytic Dia 10mm Pitch 5mm 1000UF 25V Capacitor Boxed Polyester 5mm Pitch 10% 63V 100N Capacitor Boxed Polyester 5mm Pitch 10% 63V 100N Capacitor Boxed Polyester 5mm Pitch 10% 63V 100N Capacitor Boxed Polyester 5mm Pitch 10% 63V 100N Capacitor Radial Electrolytic Dia 10mm Pitch 5mm 220UF 50V Capacitor Radial Electrolytic Dia 5mm Pitch 5mm 10UF 50V Capacitor Radial Electrolytic Dia 5mm Pitch 5mm 10UF 50V Capacitor Radial Electrolytic Dia 5mm Pitch 5mm 10UF 50V Capacitor Radial Electrolytic Dia 5mm Pitch 5mm 10UF 50V Capacitor Boxed Polyester 5mm Pitch 5% 100V 1NF Capacitor Radial Electrolytic Dia 10mm Pitch 5mm 470UF 25V Capacitor Radial Electrolytic Dia 10mm Pitch 5mm 470UF 25V Capacitor Radial Electrolytic Dia 5mm Pitch 5mm 10UF 50V Capacitor Radial Electrolytic Dia 5mm Pitch 5mm 47UF 35V Capacitor Ceramic 5mm Pitch 50V 10% 100nF Capacitor Ceramic 5mm Pitch 50V 10% 100nF Capacitor Ceramic 5mm Pitch 50V 10% 100nF Capacitor Ceramic 5mm Pitch 50V 10% 100nF Capacitor X2 Boxed Polypropylene 22.5mm Pitch 275V 470NF Capacitor Ceramic 5mm Pitch 50V 10% 100nF Capacitor Ceramic 5mm Pitch 50V 20% 1nF Capacitor Ceramic 5mm Pitch 50V 20% 1nF Diode 1N4003 DO-41 Package Diode 1N4003 DO-41 Package Diode 1N4003 DO-41 Package Diode 1N4003 DO-41 Package Diode 1N4003 DO-41 Package Diode 1N4003 DO-41 Package Diode 1N4003 DO-41 Package Diode 1N4003 DO-41 Package Diode 1N4003 DO-41 Package Diode Small Signal 1N4148 DO-35 Package Diode Small Signal 1N4148 DO-35 Package Diode Small Signal 1N4148 DO-35 Package Diode Small Signal 1N4148 DO-35 Package Diode Small Signal 1N4148 DO-35 Package Diode Small Signal 1N4148 DO-35 Package Diode Small Signal 1N4148 DO-35 Package Diode Small Signal 1N4148 DO-35 Package Diode Small Signal 1N4148 DO-35 Package Diode Small Signal 1N4148 DO-35 Package Diode Small Signal 1N4148 DO-35 Package DIODE SCHOTTKY 1N5711 DO-35 Package Zener Diode 0.5W BZX79C4V7 DO-35 Package FUSE BUSSMANN S504 T315mA 20MM FUSEHOLDER 20MM PCB FUSEHOLDER COVER TO SUIT 8S004 FUSE BUSSMANN S504 T315mA 20MM FUSEHOLDER 20MM PCB FUSEHOLDER COVER TO SUIT 8S004 FUSE BUSSMANN S504 T315mA 20MM FUSEHOLDER 20MM PCB FUSEHOLDER COVER TO SUIT 8S004 FUSE BUSSMANN S504 T4A 20MM FUSEHOLDER 20MM PCB FUSEHOLDER COVER TO SUIT 8S004 FUSE BUSSMANN S504 T4A 20MM FUSEHOLDER 20MM PCB FUSEHOLDER COVER TO SUIT 8S004 FUSE BUSSMANN S504 T4A 20MM FUSEHOLDER 20MM PCB

L925 Controller Board Parts List Issue 1.2
Designator Part
F105-2 F106 F106-1 F106-2 HS100 HS101 IC100 IC100-1 IC101 IC102 IC103 IC104 IC105 JP100 LED300 LED301 LED302 LED303 LED304 LED305 LED306 PB PL200 PL201 PL202 PL203 PL204 PL205 PL206 R100 R101 R102 R103 R104 R105 R106 R107 R108 R109 R110 R111 R112 R113 R114 R115 R116 R117 R118 R119 R120 R121 R122 R123 R124 R125 R126 R127 R128 R129 R130 R131 R132 R133 R134 F022 C12406 8S004 F022 F007 F007 L022AY 8S040 5J74259 5J74259 5J74259 5M393A 5T4N35 8K004 3D002 3D002 3D002 3D002 3D002 3D002 3D002 L925PB 8K2910 8K2910 8K2910 8K2910 8K2910 8K2910 8K2910 1W115A 1W115A 1W115A 1E410 1H347 1H347 1H322 1H322 1H310 1H310 1H310 1H222 1H410 1H410 1H410 1H110 1H110 1H147 1H222 1H310 1H222 1H222 1H222 1H222 1H222 1H222 1H222 1H222 1H222 1H222 1H222 1H247 1H247 1H247 1H247

Description
FUSEHOLDER COVER TO SUIT 8S004 FUSE BUSSMANN S504 T4A 20MM FUSEHOLDER 20MM PCB FUSEHOLDER COVER TO SUIT 8S004 HEATSINK TO-220 23 degC/W CLIP ON HEATSINK TO-220 23 degC/W CLIP ON PROGRAMMED PIC16F877 WITH SOFTWARE FOR P7 IC SKT 40PIN 0.6IN IC 8 BIT ADDRESSABLE LATCH 74HC259N IC 8 BIT ADDRESSABLE LATCH 74HC259N IC 8 BIT ADDRESSABLE LATCH 74HC259N IC COMPARATOR LM393AN DIP-8 PACKAGE Opto Isolator 4N35 CON JUMPER SOCKET 0.1IN GOLD BLUE LED 5mm Red/Green Tricolour SPR-54MVWT LED 5mm Red/Green Tricolour SPR-54MVWT LED 5mm Red/Green Tricolour SPR-54MVWT LED 5mm Red/Green Tricolour SPR-54MVWT LED 5mm Red/Green Tricolour SPR-54MVWT LED 5mm Red/Green Tricolour SPR-54MVWT LED 5mm Red/Green Tricolour SPR-54MVWT BLANK PCB CONTROLLER FOR MULTI CHANNEL AMP CON VERT HEADER 10WAY CON VERT HEADER 10WAY CON VERT HEADER 10WAY CON VERT HEADER 10WAY CON VERT HEADER 10WAY CON VERT HEADER 10WAY CON VERT HEADER 10WAY Resistor Axial Wirewound 17W 5% 150R Resistor Axial Wirewound 17W 5% 150R Resistor Axial Wirewound 17W 5% 150R Resistor Carbon Film 1W 5% 100K Resistor Metal Film 0.25W 1% 47K Resistor Metal Film 0.25W 1% 47K Resistor Metal Film 0.25W 1% 22K Resistor Metal Film 0.25W 1% 22K Resistor Metal Film 0.25W 1% 10K Resistor Metal Film 0.25W 1% 10K Resistor Metal Film 0.25W 1% 10K Resistor Metal Film 0.25W 1% 2K2 Resistor Metal Film 0.25W 1% 100K Resistor Metal Film 0.25W 1% 100K Resistor Metal Film 0.25W 1% 100K Resistor Metal Film 0.25W 1% 100R Resistor Metal Film 0.25W 1% 100R Resistor Metal Film 0.25W 1% 470R Resistor Metal Film 0.25W 1% 2K2 Resistor Metal Film 0.25W 1% 10K Resistor Metal Film 0.25W 1% 2K2 Resistor Metal Film 0.25W 1% 2K2 Resistor Metal Film 0.25W 1% 2K2 Resistor Metal Film 0.25W 1% 2K2 Resistor Metal Film 0.25W 1% 2K2 Resistor Metal Film 0.25W 1% 2K2 Resistor Metal Film 0.25W 1% 2K2 Resistor Metal Film 0.25W 1% 2K2 Resistor Metal Film 0.25W 1% 2K2 Resistor Metal Film 0.25W 1% 2K2 Resistor Metal Film 0.25W 1% 2K2 Resistor Metal Film 0.25W 1% 4K7 Resistor Metal Film 0.25W 1% 4K7 Resistor Metal Film 0.25W 1% 4K7 Resistor Metal Film 0.25W 1% 4K7

L925 Controller Board Parts List Issue 1.2
Designator Part
R135 R136 R137 R200 R201 R202 R300 R301 R302 R303 R304 R305 R306 R307 R308 R309 R310 R311 R312 R313 RC100 REG100 RELAY100 RELAY101 SK100 SK101 SK102 SK103 SK104 SK105 SK106 SK107 SK108 SK109 SK110 SK111 SK112 SK113 SK114 SK200 SK201 SK300 SK301 SK302 SW300 TH100 TR100 TR101 TR102 TR103 TR104 TR105 TR106 TR107 TR108 TR109 TR110 TR111 TR112 TR113 TR114 TR115 TR116 X100 1H247 1H247 1H410 1H210 1H222 1H210 1H122 1H122 1H122 1H122 1H122 1H122 1H122 1H122 1H122 1H122 1H122 1H122 1H122 1H122 2K410R 5D7805 A220 A220 8K2308 8K2306 8K2306 8K2306 8K2306 8K2306 8K2306 8K2304 8K6602 8K6602 8K6602 8K8516 8K6306 8K6306 8K8022B 8K8022B 8D228 8K8516 8K2402 8K2402 A1007 1T006 4A547 4A547 4A547 4A547 4A547 4A547 4A547 4A547 4A547 4A547 4A547 4A547 4A547 4A557 4A557 4B5248 4B180 7W005

Description
Resistor Metal Film 0.25W 1% 4K7 Resistor Metal Film 0.25W 1% 4K7 Resistor Metal Film 0.25W 1% 100K Resistor Metal Film 0.25W 1% 1K0 Resistor Metal Film 0.25W 1% 2K2 Resistor Metal Film 0.25W 1% 1K0 Resistor Metal Film 0.25W 1% 220R Resistor Metal Film 0.25W 1% 220R Resistor Metal Film 0.25W 1% 220R Resistor Metal Film 0.25W 1% 220R Resistor Metal Film 0.25W 1% 220R Resistor Metal Film 0.25W 1% 220R Resistor Metal Film 0.25W 1% 220R Resistor Metal Film 0.25W 1% 220R Resistor Metal Film 0.25W 1% 220R Resistor Metal Film 0.25W 1% 220R Resistor Metal Film 0.25W 1% 220R Resistor Metal Film 0.25W 1% 220R Resistor Metal Film 0.25W 1% 220R Resistor Metal Film 0.25W 1% 220R RC SUPPRESSOR 100N+100R X2 RATED 250V IC VOLTAGE REGULATOR +5V L7805CV TO-220 PACKAGE Relay 1P2T 24V Relay 1P2T 24V CON MINIFIT HCS 8WAY CON MINIFIT HCS 6WAY CON MINIFIT HCS 6WAY CON MINIFIT HCS 6WAY CON MINIFIT HCS 6WAY CON MINIFIT HCS 6WAY CON MINIFIT HCS 6WAY CON MINIFIT HCS 4WAY CON KK SERIES 0.1in VERTICAL FRICTION LOCK HDR 2WAY CON KK SERIES 0.1in VERTICAL FRICTION LOCK HDR 2WAY CON KK SERIES 0.1in VERTICAL FRICTION LOCK HDR 2WAY CON 1.00MM VERTICAL FFC 16WAY CON HDR DUAL ROW 0.1IN VERTICAL 6WAY CON HDR DUAL ROW 0.1IN VERTICAL 6WAY CON 1.00MM VERTICAL FFC 22WAY FMN SERIES CON 1.00MM VERTICAL FFC 22WAY FMN SERIES CON MIN JACK 3.5MM SINGLE CON 1.00MM VERTICAL FFC 16WAY CON CT SERIES VERTICAL 2WAY CON CT SERIES VERTICAL 2WAY SW PUSH MAINS THERMISTOR NTC 2K2 Transistor BC547B TO92 Package Transistor BC547B TO92 Package Transistor BC547B TO92 Package Transistor BC547B TO92 Package Transistor BC547B TO92 Package Transistor BC547B TO92 Package Transistor BC547B TO92 Package Transistor BC547B TO92 Package Transistor BC547B TO92 Package Transistor BC547B TO92 Package Transistor BC547B TO92 Package Transistor BC547B TO92 Package Transistor BC547B TO92 Package Transistor BC557B TO92 Package Transistor BC557B TO92 Package Transistor 2SC5248E TO220 Package Transistor BD180 TO126 Package CERAMIC RESONATOR 4.00MHz

Control PCB L925CT1_1.2.SCH

Interface PCB L925CT2_1.2.SCH

Main Switch and LED Display L925CT3_1.2.sch

DRAWING TITLE

P7 Amp Controller
Filename: Notes: L925CT0_1.2.Sch 02_E061 02_E054 02_E041
ECO No. Contact Engineer: Kevin Lamb Contact Tel: (01223) 203252

23425
A & R Cambridge Ltd. Pembroke Avenue Waterbeach Cambridge CB5 9PB

KAL KAL KAL
INITIALS Printed:

20/03/02 7/03/02 7/02/02
DATE 18-Apr-2002

CHANGED R200 VALUE. CORRECTED SK301 & SK302 TO 8K2402
JP100 ADDED ON SK112 PIS 1 & 2 , F102 PART CORRECTED TO 315mA

1.2 1.1 1.0

CHANGED C121 VALUE. REMOVED SOFT START PROTECTION PRODUCTION ISSUE PCB CHANGES ONLY
DESCRIPTION OF CHANGE

ISSUE

Sheet

1

of

4

DRAWING NO.

L925CT

FIX100 FIXING HOLE 3.2 R103 GND1 100K 2W CF NF D100 1N4003 NF R100 RES 17W 150R R101 RES 17W 150R RELAY100A RLY G2R-1E-24DC 16A SPDT TP100 5 6 7 8 1 2 3 4 X2 100N/100R AC_L F100 T315MA F102 T315MA F103 T4A F104 T4A F105 T4A F106 T4A R102 RES 17W 150R 1 2 3 4N35 NF GND1 IC105 6 5 4 +5VD R104 47K MF SSPROT*

FIX102 FIXING HOLE 3.5

FIX103 FIXING HOLE 3.5

FIX101 FIXING HOLE 3.2

FIX104 FIXING HOLE 3.5

FIX105 FIXING HOLE 3.5

TP108 MSSPROT

PB PCB L925PB_E

+ C100 4U7 50V NF
GND1

RC100

SK100 C121 470N X2 CLASS

TP101 AUX_FUSE1 SK101 MOLEXPWR6 3 2 1 115V 6 5 4

TP102 AUX_FUSE2 SK102 MOLEXPWR6 3 2 1 230V 6 5 4 TP103 AUX_TX RELAY101A RLY G2R-1E-24DC 16A SPDT

TP104 MAIN_FUSE1 SK103 MOLEXPWR6 3 2 1 115V 6 5 4

TP105 MAIN_FUSE2 SK104 MOLEXPWR6 3 2 1 230V 6 5 4

TP106 MAIN_FUSE3 SK105 MOLEXPWR6 3 2 1 115V 6 5 4

TP107 MAIN_FUSE4 SK106 MOLEXPWR6 3 2 1 230V TP131 FAN 6 5 4

TP114 MAIN_TX1 TP109 AC_N

TP115 MAIN_TX2

SK108 1 2 IDC2S

+
+22VD F101 C113 470U EL 25V

TP130 DGND_FAN

POWER TO AUX TRANSFORMER

POWER TO MAIN TRANSFORMERS
T315MA R115 100R MF TR113 BC557B R116 100R MF TR115 2SC5248 HS101 TO220HS30TR RED1 RED2 RED3 RED4 RED5 RED6 RED7 TP116 TP117 TP118 TP119 TP120 TP121 TP122 GRN1 TP123 GRN2 TP124 GRN3 TP125 GRN4 TP126 GRN5 TP127 GRN6 TP128 GRN7 TP129 RED1 RED2 RED3 RED4 RED5 RED6 RED7 GRN1 GRN2 GRN3 GRN4 GRN5 GRN6 GRN7 SK111 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 FFC16V GND1

TR114 BC557B

TP110 AUX_AC2

D101 1N4003

D105 1N4003

PWM_OUT TP111 AUX_AC1 1 2 D102 1N4003 D106 1N4003

R112 100K MF

TR100 BC547B

R118 2K2 MF

SK107 MOLEXPWR4 3 4

+ C108 10U EL
D103 1N4003 D107 1N4003 +22VD I GND HS100 TO220HS30REG O +5VD

R117 470R MF

R113 100K MF

C112 1N PE

C104 100N PE LK1

TP132 MAINS_SW

TP112 AUX_AC3 D104 1N4003 D108 1N4003

Vin

Vout

PCB NET LINK GND1

+ C101 3M3 35V EL

+ C102 1M0 25V
C103 100N PE

+ C107 220U EL 50V
REG100 7805 +5VD +22VD

TP113 AUX_AC4 +22VD_SW +22VD_SW R106 22K MF +5VD R109 10K MF R132 4K7 MF FLT_TEMP* +5VD R133 4K7 MF +5VD R134 4K7 MF +5VD R135 4K7 MF +5VD R136 4K7 MF MAINS_SW FLT_VI* WATCHDOG R114 100K MF GND1 5 7 6 LM393A TR103 BC547B MPOWER R120 2K2 MF IC104B +5VD 3 1 R110 10K MF 2 R105 47K MF IC104A R108 10K MF R111 2K2 MF TR116 BD180 PNP TO-126 D115 1N4148 RELAY100B RLY G2R-1E-24DC 16A SPDT R119 10K MF TR108 BC547B TR111 BC547B D119 1N4148 RELAY101B RLY G2R-1E-24DC 16A SPDT GND1

G

MAINS_SW

+ C111 10U EL

LM393A

PWROK*

D109 1N4148

+ C109 10U EL
TR101 BC547B

FLT_DC*

+ C110 10U EL
GND1

R107 22K MF

+ C116 47U EL 35V
MSOFT_ST* GND1

+5VD

R121 2K2 MF

GND1

GND1

THERMAL TRIPS FROM POWER TRANSFORMERS
TP133 TX_THERM2

R131 4K7 MF IC101A DATA +5VD S0 S1 S2 SEL_RED* R137 100K MF D110 1N4148 RESET* TP136 MCLR D120 1N5711 +5VD SK112 1 3 5 TP137 2 JP100 4JUMPER 6 uC_+5V UC5V RESET* DATA 13 13 4 5 6 7 9 10 11 12 RED1 RED2 RED3 RED4 RED5 RED6 RED7 +22VD_SW FAULT1 FAULT2 FAULT3 FAULT4 FAULT5 FAULT6 FAULT7 TP146 TP147 TP148 TP149 TP150 TP151 TP152 FLT_DC* FLT_VI* FLT_TEMP* TP153 TP154 TP155 FAULT1* FAULT2* FAULT3* FAULT4* FAULT5* FAULT6* FAULT7* FLT_DC* FLT_VI* FLT_TEMP* RELAY1* RELAY2* RELAY3* RELAY4* RELAY5* RELAY6* RELAY7* TR102 BC547B TR104 BC547B TR105 BC547B TR106 BC547B TR107 BC547B TR109 BC547B TR110 BC547B +22VD_SW TP166 +22V IC103A DATA S0 S1 S2 SEL_RELAY* S1 S0 PWM_OUT 13 D 1 S0 2 S1 3 S2 14 G 15 CLR IC 74HC259 Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7 4 5 6 7 9 10 11 12 RELAY1 RELAY2 RELAY3 RELAY4 RELAY5 RELAY6 RELAY7 TP159 TP160 TP161 TP142 TP162 TP163 TP164 RELAY1 RELAY2 RELAY3 RELAY4 RELAY5 RELAY6 RELAY7 RELAY1 SK114 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 FFC22V1MM

SK109 1 2 IDC2S SK110 1 2 IDC2S

D

1 S0 2 S1 3 S2 14 G 15 CLR IC 74HC259 IC102A D

TP134 TX_THERM1 TP135 DGND_SK127 GND1

Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7

+ C115 10U EL

GND1 DIL6 VPLG

S0 S1 S2 SEL_GRN*

1 S0 2 S1 3 S2 14 G 15 CLR IC 74HC259

GND1 MAINS_SW TX_OVTEMP PWROK* WATCHDOG X100 CST4.00 FLT_VI* FLT_DC* FLT_TEMP* UC5V GND1 TREF TTEMP PWM_OUT C_DISCH S0 S1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

IC100 40 FAULT7* MCLR RB7 39 FAULT6* RA0 RB6 38 FAULT5* RA1 RB5 37 FAULT4* RA2 RB4 36 FAULT3* RA3 RB3 35 FAULT2* RA4/T0CKI RB2 FAULT1* 34 RA5/SS RB1 33 TRIG/RC5 RE0/RD RB0/INT 32 UC5V RE1/WR VDD 31 RE2/CS VSS GND1 30 SSPROT* VDD RD7/PSP7 29 SEL_RELAY* VSS RD6/PSP6 28 SEL_GRN* OSC1/CLKIN RD5/PSP5 27 SEL_RED* OSC2/CLKOUT RD4/PSP4 26 RX RC0/T1OSI/T1CKI RC7 25 TX RC1/T1OSO RC6 24 MSOFT_ST* RC2/CCP1 RC5/SDO 23 MPOWER RC3/SCK/SCL RC4/SDI/SDA 22 DATA RD0/PSP0 RD3/PSP3 21 S2 RD1/PSP1 RD2/PSP2 PIC16F877

Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7

4 5 6 7 9 10 11 12

GRN1 GRN2 GRN3 GRN4 GRN5 GRN6 GRN7

D111 1N4148

D112 1N4148

D113 1N4148

D114 1N4148

D116 1N4148

D117 1N4148

D118 1N4148

TP138 RELAY1*

TP139 RELAY2*

TP140 RELAY3*

TP141 RELAY4

TP143 RELAY5*

TP144 RELAY6*

TP145 RELAY7*

C105 100N PE GND1

GND1

C106 100N PE GND1

R124 2K2 MF RELAY2

R125 2K2 MF RELAY3

R126 2K2 MF RELAY4

R127 2K2 MF RELAY5

R128 2K2 MF RELAY6

R129 2K2 MF RELAY7

R130 GND1 2K2 MF TP165 TRIG/RC5 TP167 DGND_SK131 GND1

2 4 6 +5VD 1 3 5 TREF TTEMP C_DISCH TP156 TREF TP157 C_DISCH TP158 TTEMP GND1 R122 2K2 MF TH100 THERM NTC 2K2 TR112 BC547B R123 2K2 MF IC101B IC 74HC259 VDD 16 C117 100N CD GND 8 GND1 GND1 GND 8 GND1 +5VD IC102B IC 74HC259 VDD 16 C118 100N CD GND 8 GND1 +5VD IC103B IC 74HC259 VDD 16 C119 100N CD 4 +5VD IC104C LM393A 8

SK113 DIL6 VPLG

+5VD

+
C114 470U EL 25V C120 100N CD DRAWING TITLE

P7 Amp Controller
Filename: Notes: L925CT1_1.2.sch 02_E061 02_E054 02_E041
ECO No. Contact Engineer: Kevin Lamb Contact Tel: (01223) 203252

GND1

23425
A & R Cambridge Ltd. Pembroke Avenue Waterbeach Cambridge CB5 9PB

KAL KAL KAL
INITIALS Printed:

20/03/02 7/03/02 7/02/02
DATE 18-Apr-2002

CHANGED R200 VALUE. CORRECTED SK301 & SK302 TO 8K2402 JP100 ADDED ON SK112 PIS 1 & 2 , F102 PART CORRECTED TO 315mA

1.2 1.1 1.0
ISSUE

CHANGED C121 VALUE. REMOVED SOFT START PROTECTION PRODUCTION ISSUE PCB CHANGES ONLY
DESCRIPTION OF CHANGE

Sheet

2

of

4

DRAWING NO.

L925CT

+22VD_SW2 1 2 3 4 5 6 7 8 9 10

PL200

RELAY1 TP200

ARELAY1* ASIG_PRES* AFLT_TEMP* AFLT_VI* AFLT_DC* AFAULT1

FIX202 FIX200 FIX203 FIX204 FIX205 FIX206 FIX207 FIX201 FIXING HOLE 3.5 FIXING HOLE 3.2FIXING HOLE 3.5FIXING HOLE 3.5 FIXING HOLE 3.5 FIXING HOLE 3.5 FIXING HOLE 3.5 FIXING HOLE 3.2

CON 10W 0.1 HDR CHASSIS GND2 +22VD_SW2 1 2 3 4 5 6 7 8 9 10 CON 10W 0.1 HDR GND2 +22VD_SW2 PL202 1 2 3 4 5 6 7 8 9 10 CON 10W 0.1 HDR GND2 +22VD_SW2 ARELAY1* ARELAY2* ARELAY3* ARELAY4* ARELAY5* ARELAY6* ARELAY7* TP204 A+22VD +22VD_SW2 1 2 3 4 5 6 7 8 9 10 CON 10W 0.1 HDR FFC22V1MM SK201 TP202 RC5_TRIG TP203 DGND_SK206 GND2 C200 100N CD GND2 RELAY5 TP208 ARELAY5* ASIG_PRES* AFLT_TEMP* AFLT_VI* AFLT_DC* AFAULT5 GND2 +22VD_SW2 1 2 3 4 5 6 7 8 9 10 CON 10W 0.1 HDR GND2 CHASSIS CHASSIS GND2 GND2 GND2 +22VD_SW2 1 2 3 4 5 6 7 8 9 10 CON 10W 0.1 HDR GND2 +22VD_SW2 1 2 3 4 5 6 7 8 9 10 CON 10W 0.1 HDR GND2 PL206 PL205 PL204 PL203 PL201

RELAY2 TP201

ARELAY2* ASIG_PRES* AFLT_TEMP* AFLT_VI* AFLT_DC* AFAULT2

SK200 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

AFAULT1 AFAULT2 AFAULT3 AFAULT4 AFAULT5 AFAULT6 AFAULT7 AFLT_DC* AFLT_VI* AFLT_TEMP*

RELAY3

TP206

ARELAY3* ASIG_PRES* AFLT_TEMP* AFLT_VI* AFLT_DC* AFAULT3

RELAY4

TP205

ARELAY4* ASIG_PRES* AFLT_TEMP* AFLT_VI* AFLT_DC* AFAULT4

R200 1K0 MF

JACK3.5 C201 1N0 CD

TP207 GND_RC5_TRIG