Usually, the main steps of embedded industrial control computer mainboard maintenance are checking, debugging, and disassembling. How to solve the problem of the motherboard of embedded IPC by using the method of checking, debugging and disassembling?
I. common failures of embedded IPC motherboards
1, CMOS battery failed, that is, CMOS battery failure, as long as the replacement of new batteries can be.
2. MOS check sum error-Defaults loaded, that is, when CMOS performs all checks, it finds an error and loads the system default. First replace the battery, if the problem is still not solved, indicating that CMOS RAM may be a problem, need to return to the manufacturer to repair or replace a new motherboard.
3. Press ESC to skip memory test, that is, memory check is being done, and ESC key is skipped. This is because no second, third, or fourth memory tests are set to skip memory in the CMOS, and the embedded industrial computer will perform four memory tests on boot. You can press the ESC button to end the memory check, but you need to do this every time. The solution is to select BIOS FEATURS SETUP after entering COMS settings, set Quick Power On Self Test to Enabled, and restart the embedded industrial computer after storage.
4, Keyboard error or no keyboard present, that is, disk error or missed keyboard. Check whether the keyboard connection of embedded industrial computer is loose or damaged.
5, Hard disk install failure, that is, hard disk installation failed. This is because the embedded industrial computer hard disk power line or data line may not be connected properly or hard disk jumper settings improper. Check to see if all the connections on the hard disk are plugged in and see if the jumper settings for the two hard disks on the same data line are the same. If so, just set the jumper settings for the two hard disks differently (one for Master and the other for Slave).
Two, the steps of checking, troubleshooting, and disassembling
(1) checking boards
1, the observation method: whether burn, burn, bubble, plate broken, socket corrosion.
2, table method: +5V, GND resistance is too small (below 50 ohms)?
3. Electric Inspection: For the damaged motherboard, can slightly adjust the high voltage 0.5-1V, after the start-up with the hand washboard IC, so that the problem chip heating, thus sensing.
4. Logic Pen Check: Check whether or not the signal is strong or weak at the input, output and control poles of the key suspected IC.
5. Discriminate each work area: The motherboard generally has a clear division of labor on the area, such as: control area, clock area, background picture area, action area, sound generation and synthesis area. (two) troubleshooting
1. According to the instruction of the manual, the suspected chip should first check whether there are signals in the input and output terminals, if there are signals in and out, then check whether there are control signals in the IC, if there are any, then the possibility of the IC being bad is very great, no control signals, traced to its front pole until the damaged IC is found.
2. Do not take off the IC from the pole which can choose the same model or program content from the pole for the time being. Observe whether the embedded industrial computer is better after booting to confirm whether the IC is damaged.
3. Looking for short-circuit lines by tangent and jumper method: find some short-circuit lines and ground lines, +5V or other IC should not be connected to the feet, can cut off the line and measure again, judge whether it is an IC problem or a board alignment problem, or from other IC borrowed signal welding to wave type of the IC to see whether the phenomenon picture is better, judge the IC is good. Bad.
4. Contrast method: Find a motherboard with the same content and measure the type and number of the lead wave of the corresponding IC to confirm whether the IC is damaged.
5, test IC with ICTEST software in microcomputer universal programmer.
(three) dismantling
1, cut the foot method: do not hurt the motherboard, can not be recycled.
2. Drag tin method: weld all the tin on both sides of IC foot, drag it back and forth with high temperature soldering iron, and at the same time get out IC (vulnerable board, but can preserve test IC).
3. Barbecue method: barbecue on alcohol lamp, gas stove, electric stove, etc. After the tin on the motherboard is melted, IC (difficult to master).
4. Tin pot method: Make a special tin pot on the electric furnace. After the tin is melted, immerse the IC to be unloaded on the main board into the tin pot, and the IC can be removed without damage to the plate, but the equipment is not easy to make.
5. Electric-heated air gun: Use special electric-heated air gun to unload the chip and blow the part of IC pin to be unloaded, then the IC after tin melting can be lifted out.
In addition, a common failure of embedded IPC is to press F1 after boot. The reason for this problem is the incorrect setting of CMOS. Embedded industrial computer boot self-test, you will find that some devices are not installed, so will prompt to continue by F1, but in CMOS if this device is turned on, the above problems will occur. Boot BIOS into the advanced settings options, in the menu to find floopyseek, set it to disable.