First measuring c, and d, and e three points of dB value, only e points not normal, about for 17dB, far is greater than normal (normal for 10dB), description fault occurred in pillow school output circuit, again measuring Q1305 set electrode voltage only 5 v around, and Q1304 each very voltage basic normal, check Q1305, no problem, along its output path check R1309, normal, again check C1308, found himself no capacity, replaced Hou, fault excluded.