例1 播放碟片时有较大的吭声故障现象:开机后播放碟片有图像有伴音,但有较大的响声。检修:引起该故障可能有三个原因:(1)机械及模式开关不正确;(2)进给电机驱动电路工作不良;(3)伺服电路有故障。打开机盖,反复检查机械的装配及模式开关SWA、SWB、SWC,发现 SWB 和 SWC 接触不良,用无水酒精清洗并吹干,装上再试机,响声减小。但还没完全消除,再检查模式开关,发现 SWB Example 1 play a disc when there is a large silent phenomenon: play the disc after boot image with sound, but a larger sound. Overhaul: The cause of the fault may have three reasons: (1) mechanical and mode switch is not correct; (2) feeding motor drive circuit is not working; (3) servo circuit is faulty. Open the cover, repeatedly check the mechanical assembly and mode switch SWA, SWB, SWC, found SWB and SWC poor contact, washed with anhydrous alcohol and dried, install retrial machine, the sound decreases. But not completely eliminated, and then check the mode switch, found SWB