To tell the truth, Marantz AV amp or taking very little, because this piece of Marantz products have been on the market less than, HIFI amplifier a little more. This SR5200 is very old, and least ten years, of good quality, so users could not bear to lose, is willing to fix it.Dxbservice manual download site
Dxbservice manual download site
The symptom is: left and right main channel sound reset surround sound, this failure is in the process of using a, AV amplifiers have rarely come across such failures in the maintenance, maintenance also takes some twists, let's analyze the maintenance process.Dxbservice manual download site
Theoretically analysis of the what are the causes of failure. Output relay does not move, the split volume potentiometer potentiometer after damage, damage, balance amplifier circuit may cause R/L damage causes two main channels without sound, however carefully observed this amp after the internal structure of these causes have been ruled out,Dxbservice manual download site
Dxbservice manual download site
Output circuits not designed to relay, volume control is digital, there is no balancing potentiometers, later-stage amplifier circuit after measurement has proved to be good. Measure the decoders output signal cable, only R/L two-channel signal, indicating failures before the decoders.Dxbservice manual download site
Dxbservice manual download site
Early of AV amplifier are using has more simple of decoding Board, above parts not special intensive, decoding Board has fiber and with axis entered each two group, simulation output a group, marked made AR/AL, in the reset, and surround, and Hou reset, and heavy bass are has voice, description signal switch, and Digital decoding, and DSP, circuit are normal, so problem what out in where does, is let people puzzling.Dxbservice manual download site
Dxbservice manual download site
After a double comb, confirm the output plug on the decoder Board identifies as R/L after the two signal lines are sent to the main channel audio line amplifier, by these two lines cut back, the line is very clear, because this line capacitance and inductance are identified on their respective channels, as shown in picture.Dxbservice manual download site
Dxbservice manual download site
When line is clean when it comes to the DAC chip is also not up to an analog signal, normal testing of DAC input data signals, and have had no doubt, plus bass, a total of seven channels of this machine, using two DAC chip designers must complete, perhaps because there was no seven-channel DAC chips with the technology. IC719 to CS4228A five-channel DAC with volume control DAC chip is responsible for C/SC/SR/SL/SW five-channel analog output and volume control, that if after careful observation,

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