Arcam service manual AVR400 Front Panel Board Circuit Description

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Two secondary windings from the toroidal power transformer are fed in via CN63. Pins 1, 2 and 3 con- nect to a centre-tapped secondary winding used to generate approx +/- 20VDC via the bridge rectifier diodes D603/3/4/5 and the 2,200μF 35V reservoir capacitors C609 and C610. R603 and R604 are 0.47R 1W fusible resistors for circuit protection – if they fail replace only with the same type and value.

The 3 terminal regulators IC63 and IC62 are mounted on two of the larger heatsinks near the back of the amplifier. These provide +/-15V to the op amps on the amplifier’s Input Board via the 11-way connector BN62. The Input Board also then routes the +/-15V onwards to the Front Panel Board.

Pins 4 and 5 of CN63 receive AC from another transformer secondary to generate approx +15VDC via the heatsink mounted bridge rectifier D601 and the 18,000μF 25V reservoir capacitor C631. F601 and F602 are hard wired 6.3Amp T (time delay) fuses for circuit protection – if they fail replace only with the same type and value.

This +15V unregulated supply has 4 main outputs:-

1)It is regulated down to +12V with the low dropout (LDO) 3 terminal regulator IC64. This is situ- ated on the heatsink closest to the Main Board, near the back panel. Its output goes to BN62 for the +12V triggers and also to CN501, to drive the power amplifiers’ cooling fans.

2)It supplies the HDMI Board via CN61. To minimize ripple currents in the ground return, Q643 is wired as a low dropout voltage follower with low pass filtering via R650 and C569.

3)It feeds the switched mode buck regulator IC61 via L631 and C615. The tank circuit comprises L632, C640 and C641, discharged via D631. R636 and C643 make up a snubber to reduce over- shoot. This provides a high current +5V supply to the Input Board via pins 4 and 5 of BN62. This 5V supply also feeds two 3V3 linear regulators, IC67 and IC68. These in turn supply the audio DSP ICs on the Input Board via pins 10 and 11 of BN62.

4)It feeds the +5V 3 terminal LDO regulator IC66 via the diode D616, which itself is preceded by the smoothing network comprising R615 (2W 15R) and C615. Note IC66’s output is actually approx +5.7V because of D644 in its ground line; this is brought back to +5V after D643, to feed the relay

IC66 is noteworthy because it continues working when the amplifier is in standby.

It takes a second input from the +9V standby power supply on the Power Amplifier PCB – D616 acts as a gate to prevent this from feeding back to the +15V supply when the system is in standby. It also allows the +15V supply to override and remove the load from the +9V supply when the amplifier is fully booted up.

D606 and D607 form half of a second bridge rectifier (with the other two diodes coming from the full bridge rectifier D601). These diodes charge up the 1μF/50V capacitor C604 to +15V, generating a “mains power present” signal. The 10K resistor R614 in parallel with C604 continually discharges it so that this signal effectively disappears within about 50 milliseconds of the mains being switched off. This +15V goes to the Main Board via pin 8 of BN62, where it is used as a “pull up” signal to help control the vari- ous audio muting circuits.

AVR400 Front Panel Board Circuit Description

The Front Panel Board is a double-sided PTH PCB. It contains the VFD (Vacuum Fluorescent Display) and its associated electronics, plus the keyboard, power status LED, IR remote receiver and headphones amplifier. A daughter board carries the front panel I/O socketry. See page 1 of the schematic diagram.

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Contents Issue AVR400 Main Assembly Transformer Power Power PCBs + Feet Rear Panel + PCBs AVR400 Power Amplifier Circuit Description Page AVR400 Main Power Supplies Circuit Description AVR400 Front Panel Board Circuit Description Page AVR400 Input Board Circuit Description Analogue inputs, volume control and outputsSpdif inputs, ADCs, DACs and Audio DSPs Page System Control Microprocessors AVR400 RS232 board AVR400 Hdmi Input/Output Board Page Page AVR400 Analogue Video Board Vfdclk CN101Vfdrst 25 27 29 24 26 28Page Page Page Page 8V Total 904.33mA ADV7844 TTL OutputHdmi 24/30/36Bit FLI30336 Worst Measured Currents Change Value 33ohm--0ohmConnect pin3 Input Output S1 S0OE1 OE2 GNDAdcreg 1.8/3.3V SCALER&AnalogREGFRONTHDMIOption Schematic Diagram SBL NJW1321FP1 IC81IC83 LC74763M8CH SLch 8CH SRch 8CH Cch JK78 8CH Lch JK79 8CH Rch+15V 15VScrew Mark
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AVR400 specifications

The Arcam AVR400 is a high-performance AV receiver designed to provide an immersive home theater experience. As part of Arcam’s esteemed lineup, the AVR400 combines advanced technology with exceptional sound quality, catering to audiophiles and home cinema enthusiasts alike.

At the heart of the AVR400 is its impressive power amplification, providing 100 watts per channel across 7 channels, ensuring a robust performance capable of driving a wide range of speakers. This power output is complemented by a high-current design, which means the receiver can handle dynamic audio passages without distortion, offering clarity in both subtle and explosive soundtracks.

One of the standout features of the AVR400 is its support for various surround sound formats, including Dolby TrueHD and DTS-HD Master Audio. This allows for an unparalleled audio experience, transporting users right into the heart of the action. Additionally, the AVR400 is equipped with the latest HDMI inputs, ensuring compatibility with a multitude of high-definition sources, including Blu-ray players, gaming consoles, and streaming devices.

The AVR400 also boasts advanced video processing capabilities, supporting 4K pass-through as well as upscaling of lower-resolution content to 4K. This makes it an ideal choice for users looking to future-proof their home theater setup, as it can seamlessly integrate with modern 4K televisions while enhancing the quality of older content.

User-friendliness is another essential characteristic of the Arcam AVR400. It comes equipped with an intuitive on-screen menu system that simplifies the setup process. The inclusion of an automatic calibration system helps optimize speaker settings in accordance with the room acoustics, ensuring users achieve the best sound possible from their setup.

Furthermore, the network features of the AVR400 allow for streaming audio from various online services and wireless devices. Built-in support for DLNA enables users to access their media library wirelessly, while the USB input allows for direct playback from flash drives or external hard drives.

In terms of build quality, the Arcam AVR400 embodies the brand’s commitment to excellence. With a sleek design, high-quality materials, and an engineered chassis that minimizes vibration and interference, the AVR400 is not only visually appealing but also built to deliver performance over time.

In summary, the Arcam AVR400 is a feature-rich AV receiver offering a perfect blend of power, precision, and versatility. Whether for movie nights or music listening, it stands out as a reliable choice for those seeking high-quality audio and video reproduction in their home entertainment systems.
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