According to the usual practice, the steps of the embedded motherboard repair are to check the board, debug, disassemble and repair. In this case, Qifei Technology will solve the problems of common embedded motherboards and embedded industrial computer problems by taking examples of embedded motherboard maintenance and using methods such as checking board, troubleshooting, and disassembly. Describe the faults of 5 common embedded motherboard repairs: Multi Plug DC EV charger Shenzhen Hongjiali New Energy Co., Ltd. , https://www.hjlcharger.com
1.CMOS battery failed
Chinese explanation: CMOS battery failure.
Maintenance analysis: This shows that the CMOS battery is almost out of power, just replace the battery with a new one.
2.CMOS check sum error-Defaults loaded
Chinese explanation: CMOS found an error when performing all checks, and the system default value was loaded.
Maintenance analysis: Generally speaking, this sentence says that the battery is running out of power. You can try another battery first. If the problem is still not solved, then the CMOS RAM may have problems. If you have not been to the dealer for one year, Change a motherboard, let the dealer return to the manufacturer to fix it after a year!
3.Press ESC to skip memory test
Chinese explanation: Memory check is in progress and can be skipped by pressing the ESC key.
Maintenance analysis: This is because there is no second, third or fourth test in the CMOS to skip the memory. The boot will perform four memory tests. Of course, you can also press the ESC key to end the memory check, but each time you have to This is too much trouble, you can enter the COMS settings and select BIOS FEATURS SETUP, set the Quick Power On Self Test to Enabled, and then restart after saving.
4.Keyboard error or no keyboard present
Chinese explanation: keyboard error or missed keyboard.
Maintenance Analysis: Check if the keyboard connection is loose or damaged.
5.Hard disk install failure
Chinese explanation: Hard disk installation failed.
Maintenance analysis: This is because the power cable or data cable of the hard disk may not be connected or the hard disk jumper is not properly set. You can check if the connections of the hard disk are plugged in, and see if the jumper settings of the two hard disks on the same data line are the same. If they are the same, just set the jumpers of the two hard disks differently. (One is set to Master and the other is set to Slave).
If you encounter some problems, you can use the method of checking board, troubleshooting, and dismantling.
First, check the board method:
1. Observation method: whether there is burnt, burnt, foaming, board breakage, socket rust.
2. Table measurement method: Whether the +5V, GND resistance is too small (below 50 ohms).
3. Power-on check: For the bad board, the high voltage can be slightly adjusted to 0.5-1V. After the power is turned on, the IC on the hand-held board is used to make the problematic chip heat up, so that it is perceived.
4. Logic pen check: Check whether the signal is strong or weak at each end of the IC input, output, and control poles that are suspected.
5. Identify the major work areas: Most boards have a clear division of labor, such as: control area (CPU), clock area (crystal oscillator) (frequency division), background picture area, action area (person, aircraft), sound synthesis District, etc. This is very important for in-depth repair of the computer board.
Second, troubleshooting methods:
1. Will suspect the chip, according to the instructions of the manual, first check whether there is a signal (waveform) at the input and output terminals, if there is no input, then check the IC's control signal (clock), etc. If any, this IC is bad The possibility is great, no control signal, trace to its previous pole until it finds a damaged IC.
2. For the time being, do not remove the pole from the pole and use the same model. Or the IC with the same program content is on the back, and boot to see if it is better to confirm whether the IC is damaged.
3. Use the tangential line and jumper line method to find the short-circuit line: find some signal lines and ground lines, +5V or other multiple ICs should not be connected to the short circuit, you can cut the line and measure again, determine whether it is an IC problem or a board surface Problem, or borrowing signals from other ICs to solder to the IC with the wrong waveform to see if the picture is getting better, and judge whether the IC is good or bad.
4. Control method: Find a good computer board with the same content to measure the pin type of the corresponding IC and the number of the IC to confirm whether the IC is damaged.
5. Test the IC with the ICTEST software in the microcomputer universal programmer (ALL-03/07) (EXPRO-80/100, etc.).
Third, the computer chip removal method:
1. Shearing method: no damage to the board, can not be recycled.
2. Drag the tin method: solder the tin on both sides of the IC pin, use the high temperature soldering iron to drag back and forth, and start the IC (easy to damage the board, but can protect the test IC).
3. Barbecue method: grilling on alcohol lamps, gas stoves, electric stoves, etc. After the tin is melted on the board, IC is produced (not easy to grasp).
4. Tin pot method: Make a special tin pot on the electric furnace. After the tin is melted, the IC to be unloaded on the board is immersed in the tin pot, and the IC can be taken out without damaging the board, but the equipment is not easy to manufacture.
5. Electric heat gun: Use a special electric heat gun to unload the film, blow the part of the IC to be unloaded, and then the IC after the tin is taken out (note that the air gun should be shaken when the plate is blown, otherwise the computer board will be blown. The cost of air guns is low, generally about 300 yuan, which is one of the preferred tools for most maintenance personnel).
Another common phenomenon is that the embedded industrial computer is likely to press F1 after booting. The cause of this problem is caused by incorrect CMOS settings. When the system is booted up, it will find that some devices are not installed, so you will be prompted to press F1 to continue. However, if the device is turned on in CMOS, the above problem will occur. After booting, press DELL and set the options of some devices not on the embedded industrial control board to "off" to save the CMOS settings and restart. Solution: Boot into the BIOS to enter the advanced settings option, it should be the second menu to floopyseek, set it to disable.