Normally when receiving a PC mainboard that doesn’t flip up, we have to test the voltage ranges for multi-standard elements or not to have the ability to make a preliminary prognosis of the illness. Train you the right way to measure the mainboard voltage on the whole.
Energy to the mainboard by plugging within the 20 pin (or 24) jack, 4 pin (6 pin) for the CPU circuit and ensure the facility provide is nice. You alter the VOM meter to the 10v scale, the colour wire of the mass plug (will be hooked up to the black jack of the facility provide wire for the exhausting drive, CD for compact), the crimson foot to enter the place to be measured.
1. When the mainboard isn’t powered on.
+ Verify if the PS_ON pin on the mainboard panel has a voltage of 1.5 – 5v (relying on the kind of mainboard that’s completely different).
+ Verify the three.3v supply on the PCI slot at pin A 14. This supply is the earlier energy provide for the southbridge chip.
+ In case of lack of one of many above two voltages, the supply can’t be activated. Discuss with the article: Fixing the mainboard cannot get the facility .
2. Energy on the mainboard.
+ Measure the ram slot voltage to see whether it is sufficient, DDR 1 = 2.5v ram (measured on pin 184), DDR 2 = 1.8v voltage (measured on pin 184), DDR 3 ram voltage = 1.5 v (measured on pin 170). Discuss with the article: Measure ram slot voltage to know the right way to measure. Be aware that when the ram slot voltage is misplaced, you need to repair this primary, as a result of shedding the ram supply will lose energy to the north chip and the CPU.
+ Proceed to measure the RAM BUS supply (VTT supply), to measure the ram bus supply, you measure on the 8-pin little one resistors with 330 worth close to the ram slot. The ram bus supply is the same as 1/2 of the ram supply, VTT ram DDR 1 = 1.25v, VTT ram DDR 2 = 0.9v, VTT ram DDR 3 = 0.75v. This supply is just equal, not 100% correct. When the ram bus energy is misplaced, there may be usually a scenario the place the ram isn’t plugged in, the exterior speaker sounds, if the ram is plugged in, then im re. Normally as a result of useless IC APW 7120, RT9173C, RT8105…
+ Measure the 1.8v voltage for the chip that must be north and south, this voltage regulator circuit is normally close to the south bridge chip. You measure on the S pin of the mosfet. When this voltage is misplaced, it’s normally as a result of useless mosfet, useless ic oscillation energy or quick circuit of male chip.
+ Measure the voltage of 1.5v for the northbridge chip and CPU (technical brothers set themselves is the CPU buffer supply). By measuring on the S pin of the mosfet situated alone close to the north chip. Dropping this voltage loses energy to the CPU and the north chip.
+ Measure the voltage provided to the CPU to see if there’s a supply of about 1.2 – 1.8v? Measure by putting the crimson rod on the S pin of the mosfet, or just flip the principle the wrong way up and measure on the coil pin. Dropping CPU voltage makes the CPU chilly when powered on. Because of useless vcore supply ic, useless ic oscillation, mosfet is touched or damaged. It’s also doable that as a result of a lack of ram voltage, the chipset loses CPU energy.
That’s the technique of measuring the mainboard voltage on the whole, whenever you lose any supply, you proceed to repair that supply, want you success.
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