How to use a multimeter to diagnose the PC motherboard
Mainly by measuring the voltage, and then comparing with the test points of the normal motherboard, find out the different test points, and finally find the faulty component along the line of the test point (running the circuit), and replace the component.
1. First use the resistance measurement method to measure the ground resistance of the power supply and interface 5V, 12V, 3.3V, etc. If there is no short circuit to the ground, proceed to the next step.
2. Power on (connect the power interface, and then press the POWER switch) to see if it can be turned on. If it cannot be turned on, repair the boot circuit. If it can be turned on, proceed to the next step.
3. Test the main power supply and core voltage of the CPU. As long as the main power supply of the CPU does not exceed 2.0V, you can add the CPU (provided that there is no capacitor bulge or leakage on the motherboard when visually inspected), and at the same time jump the FSB and multiplier jumpers on the motherboard. OK (it’s best to look at CMOS), see if the CPU can work up to C, or D3 (D1 or D3 is the code of the test card, indicating that the CPU has worked), if not, go to the next step/.
4. Temporarily remove the CPU, add a dummy load, and strictly follow the test points in the data to test whether the power supply is normal. Such as: core voltage 1.5V, 2.5V, 2.5V of PG and 3.3V of SLOT1, etc., as normal for the next small work.
5. According to the data, the test clock output is normal, and the clock output is 1.1-1.9V. If it is normal, proceed to the next step.
6. See if the RESET light on the test card is normal (normally, it is the moment of power-on, the light will flash once, and then go out, when we short-circuit the RESET jumper and line, the light will flash and flash with the number of short-circuits, as if the light is normal On or often without reset), if the reset is normal, go to the next step.
7. First test the CS chip option signal of the BIOS (the signal selected for the first instruction of the CPU), which is active at low level, and then test the CE signal of the BIOS (this signal indicates that the BIOS fat data is placed on the system bus) and is active at low level.
8. If it still does not work after the above steps, first visually check whether the motherboard is disconnected, and then work to refresh the BIOS program and check whether the CPU socket is in good contact.
9. If the above steps still do not work, only the minimum system method can be used for maintenance. The steps are: replace I/O? South Bridge? North Bridge.
10. Detection interface circuit: when overhauling the interface circuit, it is generally very useful to use the resistance measurement method. Generally, the damage of the interface circuit is mainly due to the damage of the resistance, capacitance and inductance on the back side, and the specific maintenance is shown in the figure.
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Chapter：
00:00:12 - Flash Sale
00:00:26 - Network Cable Tester
00:00:47 - Electrical Wire Tracer
00:01:15 - The End
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