Recently, some netizens reacted: Sometimes the hard disk is being used, it will suddenly "Dangdang" abnormal sound appears, then it can not continue to read and write data, restart the computer again, in the BIOS Can't find the hard drive. This kind of fault, sometimes the hard disk can still be found, the typical fault performance is that the hard disk is used normally when it is turned on, but when the hard disk is used for one or two hours, the above phenomenon suddenly appears. The author encountered the most is the old hard disk, such as Quantum 10G, 15G and 20G, what is going on? In response to this problem, we specially found a maintenance expert to answer relevant questions for us. In fact, the surface of the hard disk seems to be unstable on a certain chip of the hard disk, causing the hard disk to work. But when the fault occurred, I also tried to touch the chip on the hard disk circuit board by hand. The chips were really hot, but it didn't seem to be out of control. In this case, everyone thought that the hard disk was broken, and the hard disk was over-protected, and only the new hard disk could be replaced. However, such a faulty hard drive is not necessarily a real damage, but may be a surface artifact. We only need to do a simple process to completely return to normal, and read out all the valuable data we lost. The working principle of the hard disk: When the hard disk reads and writes data, the spindle motor rotates at a high speed, and the magnetic arm is driven to perform corresponding operations under the control of the control chip to complete the reading and writing operation of the data. The high-speed rotation of the spindle motor works at a constant speed. If the power supply voltage of the hard disk changes too much, it will cause the change of the speed of the hard disk. At this time, the positioning of the magnetic arm may be inaccurate or incorrect, resulting in no normal reading of data or hard disk. Bad sectors increase. When the host needs to read and write data, it only needs to issue a command to read and write a file to the hard disk. How to read and write is performed by the hard disk itself. These operations are opaque to the host. To put it bluntly, the hard disk itself is also a computer. When the hard disk is booted, it first reads the contents of the main boot area of the hard disk, reads the partition information of the hard disk into the cache, and then reads the target operation according to the information sent by the host. The boot area information of the partition, decrypt the contents of the boot information of the target partition, and then read the FAT table and the root directory, so that any file in the target partition can be read. After the hard disk finds the target file to be read and written, the completed operation can temporarily store the result of the execution in the cache of the hard disk, then issue an interrupt request to the host, and then send the result to the data bus. This completes the command operation task of the host. Fault analysis: Why does the hard disk suddenly appear lost in the work? The hard disk needs stable voltage and sufficient current supply. If the voltage is unstable or the current supplied by the power supply is insufficient, the seek will be difficult. Hard disk “咔”咔 ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” ” In both cases, this is usually the case when the switching power supply used by our computer is insufficient or faulty. For the +5V and +12V voltage instability provided by the power supply, we can use the multimeter test to make the decision. Too high or too low will not work, generally within 10% fluctuations can be considered normal. For the case where the power supply is insufficient, we can calculate the power required for full-load operation according to the hard disk, optical drive and related configuration used by our host, compared with the switching power supply we use. In general, the power supply should be greater than 10% of the sum of the maximum power of the components, and not equal. There is also a situation in which the hard disk itself has a problem, the chip may be faulty, or the motor may be damaged, and the magnetic arm may be broken. However, the hard disk mentioned here suddenly "snap" is not caused by insufficient power supply, nor is the hard disk control chip damaged, but the poor contact between the hard disk circuit board and the magnetic arm power supply interface of the hard disk body. . The hard disk circuit board and the power supply of the disk body are not connected by pins or flexible cables, but are crimped. Because the hard disk is used for a long time, and the working environment is not good, the interface of the circuit board is tinned and oxidized. The body spring piece is oxidized, causing poor contact between the two, resulting in unstable power supply of the magnetic arm seek motor, and the seek channel is abnormal, and the hard disk cannot work normally. Troubleshooting: The solution is also very simple. Disassemble the four screws of the fixed circuit board, remove the circuit board, pick up the circuit board, and have two rows of springs on the interface side of the circuit board. We need to use water with care. Sandpaper polishes the contacts of each spring piece. At the same time, the corresponding contacts on the circuit board should also be polished, and then the circuit board can be replaced as it is. Postscript: Quantum's 10G, 15G, 20G, 40G hard drives have similar failures, which can be different from the failure of Quantum 10G, 15G hard drive circuit board burnout. The circuit board is intact and there is no trace of any damage on the surface. As long as the hard disk works normally after booting, the fault that starts to squeak in 20-30 minutes can be solved according to this method. A university computer classroom 40 DIY machines, using Quantum 15G hard drive, purchase for about two years. Suddenly there were two or three hard drives that worked hard for an hour and couldn't read the data. In less than a month, there were thirty-five machines with exactly the same problem. The warranty period of the hard disk is one year, and it has been over-guaranteeed. If the hard disk is replaced, it will cost 120,000 yuan. The machine is almost ready to be phased out, and it will not cost a lot of money to replace the new hard drive. Finally, after the hard disk is processed one by one according to the above method, it has been used for almost one year, and no problem has been found. This article comes from [System Home] www.xp85.com