motherboard voltages gone haywire
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my machine (2.6 GHz celeron on an asus m/b) has just started locking up. after a few fruitless reboots i thought that the cpu might be overheating despite the lack of warning beeps and such like. i went into the hardware monitoring part of the bios and found that the all except the 12V rail were operating at about a volt too high. ie the 3.3V rail was at 4.3V and so on. and the fan RPM was not being displayed or the CPU/case temperatures. but if i moved the selection up and down, sometimes the voltages would right themselves and all the other settings would then display correctly. for a while, and then it would jump up again. i figure that either it's a power supply problem or a m/b problem :->. but before i start trying to locate (or have to buy) a replacement power supply, has anyone else experienced this and what was the solution? ps. i'm not made of money :)
.dan.g. AbstractSpoon Software abstractspoon2_at_optusnet_dot_com_dot_au
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my machine (2.6 GHz celeron on an asus m/b) has just started locking up. after a few fruitless reboots i thought that the cpu might be overheating despite the lack of warning beeps and such like. i went into the hardware monitoring part of the bios and found that the all except the 12V rail were operating at about a volt too high. ie the 3.3V rail was at 4.3V and so on. and the fan RPM was not being displayed or the CPU/case temperatures. but if i moved the selection up and down, sometimes the voltages would right themselves and all the other settings would then display correctly. for a while, and then it would jump up again. i figure that either it's a power supply problem or a m/b problem :->. but before i start trying to locate (or have to buy) a replacement power supply, has anyone else experienced this and what was the solution? ps. i'm not made of money :)
.dan.g. AbstractSpoon Software abstractspoon2_at_optusnet_dot_com_dot_au
As for the Power Supply: You can test the PS, but the results might not be the same as if the PS was under load: Remove the PS from your computer. Disconnect all cables. Take the Mainboard-Connector. It should have 20 pins in total (if it does not, you will have to check the manual for the pin layout). Short Pin 4 to Ground with a piece of wire. How to find pin 4: the pins are numbered from top to bottom in a row-first manner. The top is the part with the plastic hook. Example: [code] |-----| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 [/code] If shorted this way, the PS should start running. Then try an measure the voltages (try formfactor or wikipedia for the appropiate pins). IMPORTANT: This is just my experience. I do take any responsibility for any damages caused to you or your equipment when following these instructions. If you do not know how to behave around electricity, DO NOT TRY THIS. As for the MB: Visually check the capacitors on your MB. They have a (usually) cross-shaped predetermined breaking point on their cap. The top of the cap should be flat. If it is deformed or broken, it is likely that they reached the end of their lifespan. In that case, you could either try and replace them with new ones (see IMPORTANT note above) or buy a new MB.
Cheers, Sebastian -- Contra vim mortem non est medicamen in hortem.
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As for the Power Supply: You can test the PS, but the results might not be the same as if the PS was under load: Remove the PS from your computer. Disconnect all cables. Take the Mainboard-Connector. It should have 20 pins in total (if it does not, you will have to check the manual for the pin layout). Short Pin 4 to Ground with a piece of wire. How to find pin 4: the pins are numbered from top to bottom in a row-first manner. The top is the part with the plastic hook. Example: [code] |-----| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 [/code] If shorted this way, the PS should start running. Then try an measure the voltages (try formfactor or wikipedia for the appropiate pins). IMPORTANT: This is just my experience. I do take any responsibility for any damages caused to you or your equipment when following these instructions. If you do not know how to behave around electricity, DO NOT TRY THIS. As for the MB: Visually check the capacitors on your MB. They have a (usually) cross-shaped predetermined breaking point on their cap. The top of the cap should be flat. If it is deformed or broken, it is likely that they reached the end of their lifespan. In that case, you could either try and replace them with new ones (see IMPORTANT note above) or buy a new MB.
Cheers, Sebastian -- Contra vim mortem non est medicamen in hortem.
Sebastian Schneider wrote:
The top of the cap should be flat. If it is deformed or broken, it is likely that they reached the end of their lifespan.
This is called Capacitor Plague and is NOT normal. See this[^] for more info. It's quite the interesting read and why I'm replacing about 1 motherboard a week where I work.
Dave Kreskowiak Microsoft MVP - Visual Basic
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Sebastian Schneider wrote:
The top of the cap should be flat. If it is deformed or broken, it is likely that they reached the end of their lifespan.
This is called Capacitor Plague and is NOT normal. See this[^] for more info. It's quite the interesting read and why I'm replacing about 1 motherboard a week where I work.
Dave Kreskowiak Microsoft MVP - Visual Basic
Actually, this also happens with capacitors manufactured by well-known companies with an intact QA-department. You can call this a case of capacitor plague ONLY if the capacitors fail spectacularly and prematurely. Since the capacitors contain an electrolyte and are rated for a specific MTBF at a given temperature, they can break if they are used outside their specified temperature window. If the capacitor is rated for 10 years at 30°C, it might well fail after 5 years in 35° or 2 years in 40°, depending on the specifications used by the manufacturer. The drop in lifespan is quite dramatic for a small increase in temperature, and the result can also involve ruptures at the predetermined breaking point when all the electrolyte is gone. This does not necessarily mean that the capacitor was badly made, but just that it was not designed to operate under this conditions. -- modified at 6:50 Thursday 17th August, 2006
Cheers, Sebastian -- Contra vim mortem non est medicamen in hortem.
