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Voltage Problems

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by mddddd

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Does anyone know of any of fixes for a motherboard that does not accept enough voltage? Any overclocking utilities that allow a user to increase the voltage intake? I know its a wierd question but my motherboard just won't accept the right amount ofvoltage for the components. Everything is below what it is suppoesed to be at and I can't change the values in the BIOS. I even have 450W power supply and the motherboard refuses to accept the right amounts of power. Any suggestions would be greatlyappreciated. Thanks.

6 replies

by guruofdos

If you are referring to low readings in the BIOS monitor, don't worry! 5v, 12v and -12v rails are all nominal values. The only critical factor for overclocking purposes is the CPU voltage. If there is not a voltage setting for CPU Plug and Play in the bios, then there will be jumpers on the motherboard. Refer to your mobo manual.

by mddddd

Hmmm.. I will try looking on the motherboard but the voltages are registering below what they should be at. Even the VCORE is low. It's causing a lot of system instablility such as frequent crashes and the picture on the monitor keeps going off and on which could be the video card not receiving enough power. Thanks for the help though.

by thechas

Time for a voltmeter.

I recommend that you get a digital volt meter, and check the DC voltages to the motherboard, and the actual output from the V-Core regulator.

Your motherboard takes the voltage from the power supply, and uses on-board voltage regulators to create a few other volatages that it needs.
If the power supply is indeed supplying the correct voltage, that voltage is present on the motherboard.

With a 450 Watt power supply, I can't imagine any reason for the power supply voltages to be low, other than a reference issue on the motherboard itself.

If the voltages are correct at the motherboard power connector, it is possible that a plug-in card or the motherboard itself is bad.

I would not be too alarmed by the on-board voltage measurement circuit being off a bit.

However, I just had another thought.
There is a batch or 2 of motherboards that were built with some bad capacitors.
Take a look at the caps on your motherboard.
(the ones to look at are cylindrical about 1/2" tall, the top looks like aluminum)
What you are looking for is evidence of a liquid leaking from the bottom of these caps.
If you see signs of liquid residue, or the caps have bulged out at the sides, unplug the PC, and contact the motherboard mfg.

Chas

by thechas

A little primer on DC power.

The motherboard cannot 'refuse' to accept the voltage from the power supply.
It can however limit the amount of current that it will draw from the power supply.

(inspect both power connectors (power supply and MB)for dirt or corrosion)

Voltage is 'similar' to water pressure, and current is 'similar' to water flow.

Water flow is easier to control and change than water pressure is.

If you have 40 PSI water pressure, it is present at that pressure in all of the connected pipes.

The same is true for voltage.
If the power supply is supplying +5, +12, -5, and -12 volts, they are present at all respective connections.

Current flow is controlled by resistance. If you have high resistance in the connections, you can have a voltage drop across the pins.
This is the only place where the motherboard can 'refuse' to accept the voltage from the power supply.

I suspect that you have a bad motherboard or plug-in card.
Start by removing the modem or network cards, as these are the most apt to fail.

The next thing to look for, is if any parts are getting hotter than they should.

Chas

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