Power Supply

Discussion in 'Computers and The Internet' started by Trotsky311, Jan 10, 2005.

  1. Trotsky311

    Trotsky311 Hip Forums Supporter HipForums Supporter

    anybody got a good way to test whether or not a powersupply is going bad?

    i've got a voltmeter, if that helps.
  2. why are you suspiciuos of it in the first place?

    my experience has been if its working its working. if the comp isn't working, its a possibility its the power supply, but could be other things as well....
  3. Trotsky311

    Trotsky311 Hip Forums Supporter HipForums Supporter

    computer runs just fine, and it's a fresh install of windows xp. I set this box up for a friend, so it's got antivirus, firewall, anti-spyware, and firefox. and all the windows updates except for sp2.

    it just shuts off at complete random. while idle, running a game or so, doesn't matter. kinda like it gets unplugged.
  4. Mui

    Mui Senior Member

    does it automatically turn the computer back on after it shutdowns or once it shutdowns it stays off?

    no error messages at all??

    what voltage is it?? What are the system specs?

    im thinking it might be because its not a high enough voltage power supply in the first place
  5. Soulless||Chaos

    Soulless||Chaos SelfInducedExistence

    Sounds like it's too weak... :rolleyes:
  6. EllisDTripp

    EllisDTripp Green Secessionist

    Yeah, you use a voltmeter. :)

    Now that you mention it, it would. :)

    Take one of the unused drive power connectors, and insert the negative meter lead into the hole for one of the black (ground) wires, and leave it there for all tests. With the meter set to measure DC voltage, check the voltages on the red and yellow wires in the connector. The red should be 5 volts +/- 0.1 V or so, and the yellow wire should read 12 volts +/- .5 V.

    If these checks are OK, the power supply is most likely OK, but a few checks are needed to be 100% sure. The power supply also puts out -5V and -12V rails, and newer (ATX) units also supply +3.3V (usually orange wires) and a second +5V source (usually purple) that stays on as long as the supply is plugged in. The wire colors for these may vary with manfacturer, but they are all in the power cable that feeds the motherboard. There is also a logical signal called "PG" or "power good" that will read a logic "1" (near 5V) if all the supply outputs are within spec. This is usually on a grey wire.

    If all the voltages are OK, and they stay stable, then the power supply is not the problem.
  7. psilonaut

    psilonaut Mushroom Muncher

    Monitor your voltage in your BIOS settings or use a diagnostic program like Aida32
  8. EllisDTripp

    EllisDTripp Green Secessionist

    I would trust a digital voltmeter connected to the power rails over any kind of software utility any day. Seeing as the software is running on a computer that may or may not be seeing the proper supply voltages (including the ones it needs for a measurement reference!), a "second opinion" from a independent instrument is a good "reality check".
  9. psilonaut

    psilonaut Mushroom Muncher

    Agreed. But a good diagnostic tool can generate fancy graphs!
  10. I doubt the power supply is the problem. usually if a power supply dies -- its dead.

    Not saying its NOT the power supply, but to me seems unlikely, especially since this is a new machine that you built.

    I bet your RAM is not 100% compatible with the motherboard, or the RAM is not in the correct slots on the motherboard.

    These day's PC Motherboards need RAM that is 100% compatible, and the type may not be enough, you may have to narrow it down to the manufacturer. Also if you have a 128 MB stick, it may have to go in one specific slot rather than a 256MB or 512MB stick. Don't know why they have it that way, but it is on a lot of new motherboards.

    Do this.

    Go to the MOBO manufacturer's website. Pull up the support page for your EXACT motherboard. They should have a list of "certified" compatible hardware, which means that the manufacturer of the MOBO has guarunteed it will work. Try RAM from that list, and also make sure that you get it in the correct slots.

    Other then that, if there is a bunch of Peripherals (printer, scanner, speakers, zip drive, etc) hooked into the machine -- they cuold be sucking the power out. Also a lot of Video cards require a lot of power, what kind of video card do you have in it?

    Lots of places to look. ;) keep us updated.
  11. I have had an issue that caused the symptoms you describe exactly with RAM and with too many Peripherals which is why i suggest it.

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