Main products: power adapter, medical power, LED power, charger and so on.
Shenzhen Lianyunda Electronics Co., Ltd. is committed to doing a good job in power supply products, and sincerely welcomes customers to contact us by phone or email.
Symptom: A Lenovo IdeaCentreB31r3 integrated microcomputer is less than a few days and then 10 days and a half months, and occasionally a crash occurs. At this time, the phenomenon is that the power adapter and some of the indicators are long and black, which seems to enter the energy-saving state, but cannot be activated by the keyboard, mouse or the power-on button. Press and hold the power button to turn off the power, and then turn it off immediately after the power-off. This failure mostly occurs in winter.
Analysis and overhaul: Originally thought that the mains supply, power adapter, memory card, system problems or viruses, but eventually were excluded. During the overhaul, it was also found that after the machine was shut down forcibly, just plug the power adapter output side plug for a few seconds and then plug it in again, the machine can be turned on normally and work for a long time. In addition, it was found that (the only one time) the upper part of the back cover of the machine also emitted a slight "squeaky" sound similar to electrostatic discharge. Suspected that the fault is related to electrostatic discharge, decided to open the cover.
In addition to the keyboard and mouse, the LCD monitor, hard disk, optical drive, motherboard, etc. are all assembled together, very compact, similar to a laptop computer, with no fixing screws around. Disassemble the machine: Place the LCD screen face down, firmly pull the fixing bracket to the vertical position, push the lock in the middle of the bottom of the bracket to the locked position, remove the two screws of the fixing bracket, and remove the fixing bracket. Then, start from the semi-circular notch of the back cover, expand the gap between the notch and the back cover, and then use a wide-headed screwdriver to slowly enlarge the gap and gradually advance along the optical drive and the upper and lower sides of the screen toward the USB interface. When the rear cover on the side of the optical drive is opened, gently shake it up and down and push it toward the USB side to remove the entire back cover. There is no fixed pin on the side of the USB power adapter. There are various interfaces embedded in the side of the back cover to position the card. If you are from here, it is easy to break the interface and the back cover.
Check the motherboard, the backlight board, especially the power adapter and the electrolytic capacitors around the CPU. No abnormalities are found, and the panel buttons are not leaking. The upper part of the back cover of the machine is a CPU cooling fan. The sound similar to the electrostatic discharge seems to be emitted from here. There is a lot of dust here. After the dust is removed, the surface of the CPU is coated with thermal grease, and some connectors are reinserted to strengthen the contact. The aluminum foil adhered between the components in the machine has a large resistance or even no resistance at all. The part is degummed to leak out the conductive surface, and then pressed and pasted firmly. The test machine has been normal for 3 months now. But the fault is caused by the static electricity in the winter air, or other problems, has not been clear, it is a pity.