How to use a motherboard diagnosis card

The motherboard diagnostic card is also called the post card, which is an essential tool for mainboard repair. Every time the motherboard BIOS is started, all components of the system, such as the circuit, memory, keyboard, video, hard disk, and soft drive, are strictly tested and analyzed, initialize the configured Basic I/O settings, and import the system to the operating system after the configuration is normal. The principle of the motherboard diagnosis card is to use the detection results of the internal self-check program of the motherboard BIOS and display them one by one through the code to find the computer motherboard fault.
　　

At present, the motherboard diagnostic cards on the market are similar, some of which only differ in some features. Therefore, the following describes how to use the diagnostic cards.

1. diagnostic display code.
　　
2. Turn off the power supply and remove all expansion plug-in cards.
　　
Insert the diagnostic card into the ISA slot or PCI slot (Note: The component surface of the diagnostic card faces the power supply. If the plug-in is reversed, the current card and the motherboard will not be damaged, but they will not work .)
　　
3. Open the power supply and check whether the LEDs indicate normal (the BIOS signal may flash ).
　　
4. If it is abnormal, turn off the power, and troubleshoot the error by referring to the following "indicator function quick query table". After troubleshooting, return to step 1.
　　
RUN lamp (bus pulse )?? If the motherboard runs the command, the light will shine, otherwise it will not light up.
　　
CLK lamp (bus clock )?? The CLK signal of the ISA, PCI, or MiniPCI bus of the desktop computer.
　　
BIOS (BIOS reading signal )?? When the diagnostic card is inserted in the ISA cable slot, the BIOS will shine when the motherboard is running and there is a read operation on the BIOS. The four-digit diagnostic card is the opposite.
　　
IRAY (the master device is ready )?? Only when there is an IRAY signal is on, otherwise it is not on.
　　
FRAME (FRAME cycle signal )?? When there is a cyclic frame signal in the pciipc or MiniPC slot, the light is shining.
　　
OSC (ISA Oscillation )?? It is the main oscillation signal of the ISA slot, and the power of the blank board should be always on; otherwise, the crystal oscillator circuit of the motherboard does not work, but does not have the OSC signal.
　　
RST (reset )?? After the RESET switch is enabled or switched on, it is normal to turn off for half a second. If it is not switched off, the RESET pin on the motherboard is often mistakenly connected to the accelerator switch, or the RESET circuit is bad.

12 V (power supply )?? When the blank board is powered on, it should be on. Otherwise, there is no such voltage or the motherboard has a short circuit.
　　
-12 V (power supply )?? Same as above.
　　
-5 V (power supply )?? Same as above (only the ISA slot has this voltage ).
　　
5 V (power supply )?? Same as above.
　　
3.3 V (power supply )?? The 3.3V voltage exclusive to the PCI and MiniPC slots of the desktop microcomputer and the laptop is always on when the blank board is powered on. If the PCIe slot or MiniPC slot of some boards is not on the 3.3V voltage, the system will not be on.
　　
5. Check whether the POST code is correct.
　　
6. If there is an error, turn off the power, and troubleshoot according to the meaning of the "POST code". After the troubleshooting is completed, return to step 1.
　　
7. Turn off the power supply, plug in the graphics card, I/O Card, hard drive and expansion card, then turn on the power, check the POST code.
　　
8. If there is an error in the POST code, turn off the power, and troubleshoot according to the meaning of the "POST code". After the troubleshooting is complete, return step 1.
　　
9. The detection result is normal. Self-check should be successful. If you still cannot boot the operating system, it should be software problems (or disk drivers, disk controllers, DMA circuit faults, etc ).