By the phenomenon of failure analysis: the sound of the machine is always normal, which shows that the power supply, laser head, RF signal processing, DSP digital signal processing, servo circuit, microprocessor, etc.. According to the principle of the sound circuit of the decompression circuit, the sound is normal. Faults may be produced in the video coding circuit W9952QP, and its peripheral components. Using the meter to measure the W9952QP pin voltage, basically normal. Suspected W9952QP peripheral components are faulty. Use the digital million to test their peripheral chip resistance, no exception. Due to the leakage of the patch capacitance on the board is prone to leakage, so that the W9952QP peripheral patch capacitance detection, nothing. Carefully check the connection between the W9923QF and the W9952QP copper foil, also found no problem. Try changing W9952QP, but the fault is still.

Touch to dynamic random access memory (DRAM) feel a temperature rise, doubt DRAM damage, because touch DRAM, there should be no temperature l feel. The DRAM model for KM416C256AJ-7, to find the same type of DRAM for, troubleshooting. Long time testing machine, figure sound normal.