Measured drawings IC202 (18), (19) feet of positive and negative vCC power supply. Measuring amplifier block IC202 (STK400-090) (6) pin input signal to meet the requirements. (20) the output signal of the feet is also normal, IC202 amplifier itself undesirable possibility is very small.yfWservice manual download site
At this point. Has "failed" parts down to IC202 (20) feet to the CON104 connection between the circuits and components. Check the filter inductor without unsoldering and abnormal phenomenon, grounded capacitors C233 logging without leakage.yfWservice manual download site
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At this point, the component checks the check found no "fault" points. Ruminated and measure the resistance to ground. Trying to gain more analysis for clues and ideas. Along the signal alignment testing. Found filter inductance to resistor value is too small (1k boy trunk). According to circuit analysis.yfWservice manual download site
Its resistance to ground should be 1M XI meteorite thin? Walk the line between stupid Tuo CB Board definitely has serious leakage problems, thereby causing signal attenuation, bypass, and resulted in decrease of the sound. So with a knife when paddling out space between lines and alcohol clean after washing, to block the leakage path.yfWservice manual download site
Processed by the above measure the resistance zuzhi is close to infinity, power test "failed" excluded.yfWservice manual download site