These two "faults" are independent of each other.Z28service manual download site
Z28service manual download site
This machine is Onkyo's early flagship amplifier, dual decoding functionality through pure final stage features compact machine layout, material is sufficient. Massive toroidal transformer sealed within a black shell, set on the front panel, this method of installation is rare. Two big reservoir 50MM diameter, high 120MM, enough to know the weight of this machine.Z28service manual download site
Z28service manual download site
First disassemble the amplifier's internal structure to text, from back to front, chassis separated into two parts, the left is a few risers, right part tiled Board. Left first Zhang vertical Board is small voltage Board, shell has a layer aluminum shell is thermal device, this Board Shang is 5 v, plus or minus 12 v, small voltage, second Zhang vertical Board for audio signal entered conversion Board, this Board not only for switch directly entered of audio signal, decoding Board sent to of signal also through this Board rushed to Qian level, Board of upper has a bundle more unit of shield line is eventually output to amplifier level of 7.1 channel signal.Z28service manual download site
Z28service manual download site
Third vertical plates under audio signal input for the video channel, the fourth gold risers for the video input signal and decoding, the fifth block plate for s-video signal input, the sixth gold risers for a digital signal input Board, fiber optic and coaxial signal decoded through some plate onto a second plate.Z28service manual download site
Z28service manual download site
Right half of the upper is a boxy preamp Board, made up of seven separate channels, is not difficult to see from the layout of the triode, which also brings a great deal of convenience for maintenance, and disconnect the attachment plate to the back stage, the whole works, so that you can easily find out which one channel out of the "failed". Take apart preamp Board can be seen below the amplifier after, after the stage part fixed on top of the two pieces of aluminum radiator, although the volume is not large, but both ends of the radiator there are two fans enough time to drain away the heat. Seven-channel split into two groups on the radiator, are individually designed seven split plates, can be removed separately, maintenance is very convenient, except that the design was too loose, remove the connection wire is inconvenient. After amplifier composed of three-stage, the first stage is C4323/A1360, the second is C4883/A1859, ultimate amplifying tube for C3859/A1494, vent pipe for the three original amplifier tube, good performance. After the level has a vertical panel on the right side is Dianyuan power standby Board.

 2    1 2 Next Last