According to the customer: This machine was originally a flower screen, sometimes it will be good, and it will be repaired by an acquaintance, and it will become a sound now.
It is understood that a set of dg5 socket and plug contact failure on the d board of this machine is a common problem, so the buzzer is used to measure the contact between the socket and the plug. (The needle needs to be made with a special steel needle. I found that the next row has two feet, the plug is removed, the measuring line is good with the copper piece, and the thing is definitely on the socket. When the positive circuit board is removed, there are two copper strips (very thin) that are overwhelmed. Carefully pull the two copper strips back to the original place with a thin steel needle, and then insert it again, ok! (The whole socket and plug are treated to make it close to each other before insertion.) I realized that I should use good elasticity here. The tin-phosphorus-copper skin, the assembly manufacturer in order to save costs and not used according to the requirements, will produce this common problem! I saw on the Internet that some of the posts said that it was a flower screen. When the plug was unplugged and reinstalled, it became dull and sound. It seems that the root cause of the fault is the copper strip of this socket. Refer to the fault!