This is veteran YAMAHA 3090, imports from Hong Kong 18 years ago, when cities like Chongqing in estimated domestic market there are very few pure imported machinery sales, from about 95 after fever after a wave swept the country rapidly, until ten years after the long faded. So today the four audio brand in the domestic fever's fame has diminished, because many of the fancier from entry starts with the exposure to these brands, such as YAMAHA, Yamaha.A5aservice manual download site
A5aservice manual download site
Yamaha DSP-A3090 were listed in 1997 Center for a top home audio amplifier, matching with the DVD, and LD with a AC-3 output. It in 5.1-channel was added on the basis of two roads in the front left, front right surround, formation of Yamaha's unique seven-channel form, be one of the largest number of a variety of home audio center channel.A5aservice manual download site
A5aservice manual download site
The amplifier is actually several such as DSP-A1 machine's forerunner, was it rough prototypes before the domestic, internal layout and materials are the same. When he arrived at Chongqing into a stereo repair shop to symptoms are as follows: normal boot play music, normally each channel output was about jumping playback channel selection switch in a few minutes, is always irregular rotation to find the signal path, when you select the channel with the remote control switch does not correctly select is still spinning. According to the analysis, this problem is in the motor control circuit or identification circuit.A5aservice manual download site
A5aservice manual download site
A5aservice manual download site
After the machine apart to find the signal channel control section, this is a piece by the motor, the control chip, chip select switch assy. Detection of first step is measurement small motor of performance, alone powered proved its pros and cons turned are normal powerful, measurement control chip of work power, and output voltage are normal, analysis circuit Hou learned that it of location detection is from conversion switch Shang sampling level to control motor of, so if switch of contact tablets oxidation or up halogen are may caused chip detection not to location, so motor kept of turned to find location,

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