Fault phenomenon of servo circuit and system control circuit is normal, abnormal failure are decoding board work. First detection + 5 V and + 3.6 V voltage is normal, because of a malfunction only appear when playing, and servo signal transmission between processing and decoding board only three fuses, namely LCK, BCK and DAT, another one is decoding board provide 16 MHZ clock signal to the servo. Decided to take after the first difficult maintenance way, check again after transmission line circuit board components. LCK, BCK and measuring voltage of the DAT are 2.6 V is normal, when the test voltage of the 16 MHZ signal lines, found between 2 V ~ 2.6 V voltage fluctuations, with his hand upon the lead voltage change is bigger, and voice also instantly become clear, that the attachment have poor contact phenomenon. CKvservice manual download site
Finally find out servo board line socket is loose, after cleaning treatment of commissioning, figure sound clear. Failure analysis and form interference because of unstable contact resistance, make the change to the decoder of the clock signal, seriously affect the output audio signal.CKvservice manual download site