Usually, the steps to repaire embedded computer motherboard repair are checking the board, debugging, disassembly and repairing. In this case, Shenzhen Innovative Cloud Computer Company will demonstrate how to solve the common embedded motherboard and embedded industrial control machine problems by taking the embedded motherboard as an example.
There are five common faults for embedded computer motherboards.
1. CMOS battery failed
It shows that the CMOS battery is almost out of power. Then just change batteries.
2.CMOS check sum error-Defaults loaded Fault Discription: CMOS found an error when performing all checks, and the system default value was loaded. Generally speaking, it says that the battery is running out of power. We can try another new battery first. If the problem is still not solved, the CMOS RAM may have problems.The only way to return the motherboard to the dealer. 
3.Press ESC to skip memory test Fault Discription: Memory check is in progress and can be skipped by pressing the ESC key. It is because there is no second, third or fourth test in the CMOS. Let us skip the memory. It will perform four memory tests after boot. Of course, we can also press the ESC key to end the memory check, but we have to do the same each time. We can enter the COMS settings and select BIOS FEATURS SETUP, set the Quick Power On Self Test to be Enabled, and then restart system after saving. 4.Keyboard error or no keyboard Fault Discription: keyboard error or missed keyboard. Please check if the keyboard connection is loose or damaged. 
5.Hard drive installation failure Fault Discription: Hard drive installation failed. It is because the power cable or data cable of the hard drive may not be connected or the Hard Disk jumper is not properly set. We can check if the cable connections of the hard drives are plugged in, and if the jumper settings of the two hard drives on the same data line are the same. If they are same, just make the jumpers settings of the two hard drives different. (One is set to Master and the other is set to Slave). If we encounter some problems, we can use the methods of checking board, troubleshooting, and dismantling. First, check the motherboard: 1. Observation: to see if there is burnt, , foaming, board breakage, socket rust. 2. Table measurement: to see if the +5V, GND resistance is too small (below 50 ohms). 3. Power-on check: the high voltage can be slightly adjusted to 0.5-1V for the non-working board. The IC on the hand-held board is used to make the problematic chip heat up, so that it is perceived after the power is turned on. 4. Logic pen check: to check whether the signal is strong or weak of the input of suspected IC , output, and control poles. 5. Identify the major work areas: Most circuit boards have a clear division, 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, troubleshoot:
1. According to the user instruction of the motherboard, first check the chip to see if there is a signal (waveform) at the input and output terminals. If there is no input, please check the IC's control signal (clock), etc. If any, this IC is broken with high possibility, if no control signal, please trace to its previous pole until it finds a damaged IC.
2. Do not remove the pole from the pole for time being and use the same model. Or it is better to put the IC with the same program content on the back, and boot to see if it is damaged.
3. Find the short-circuit line with the tangential line and jumper line method. Find some signal lines and ground lines, +5V or other multiple ICs that should not be connected to the short circuit, then we can cut the lines and measure again, to determine whether it is an IC problem or a board surface Problem, or using the signals from other ICs to be soldered to the IC with the wrong waveform to see if the disply is getting better, and judge whether the IC is good or bad.
Shenzhen Innovative Cloud Computer co.,Ltd. is a professional Mini Computer manufacturer. It provides Industrial PC, Firewall Appliance, home & Office PC, etc.
Company: Shenzhen Innovative Cloud Computer Co., Ltd.
Email: sales03@cnxcy.com.cn
Whatsapp: +8615019401196
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Shenzhen Innovative Cloud Computer Co., Ltd.
March 02, 2023
