hp pavilion t3000 PSU power supply problem ?

Discussion in 'Computer Games and General Discussion' started by markyboy77, Feb 5, 2011.

Feb 5, 2011
  1. markyboy77
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    Newcomer markyboy77 Member

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    hey guys

    i have a problem with my pc

    its a hp pavilion t3000

    my electric ran out and when i came back to turn the electric on everything was ok but my PC . it just wont start when i try to turn it it nothing happens no noise of fans of anything , i looked at the back of the tower and noticed a Solid green light . after doing a bit of research on the net i went to the HP site and various others . they all said that a green solid light was not a PSU problem .

    so i took out the batter on my MB and reset the bios jumper and tried it still nothing , i also disconneced everything mouse keyboard any USB connections everything , i took out the RAM and tried to load it and still nothing , i also put the ram in and took out all the AGP and PCI slot but still nothing arghhhh .

    any help would be much apreciated

    thanks in advance

    marky
     
  2. Originality

    Member Originality Chibi-neko

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    When faced with computers that won't turn on, I find I only have a 50% chance to fix it - that always depends on what exactly the cause is.

    First, the unreliable step - with the case open (to look inside), turn the power off from the wall, then turn it back on. Immediately after, press the on switch. From experience, this'll create a power surge that'll fix it 10% of the time. If it doesn't work, the important thing to check for is if the fans move at all.

    If the fans don't move, double check the front panel headers, specifically PWR_SW. You can just try connecting the pins with a copper wire or something for a second to try triggering the power up sequence, although it's exceedingly rare for something to go wrong with the headers outside a broken switch (from pushing it too hard) or static short circuit (reseating the FP connectors will fix that).

    If the fans do move, then it's a little more complicated. The green light can either be from an ethernet port (unusual to be lit when it's off, except with certain BIOS configurations), or from a "live indicator" on the motherboard (to tell you it's got power going through it and you shouldn't poke it too much). If the fans move but only get less than 10 revolutions, then it usually means there's a problem with the power phasing of the motherboard - either a short circuit or a failure to get enough power on the 12V rail (the big power plug that plugs into the motherboard).

    I have mixed success in fixing computers at this stage of diagnostics. I usually unplug everything from the motherboard (bar the CPU, although I do reseat the CPU fan connector), check all the capacitors for bulging caps, give it a good clean to remove dust or hairs (hairs are common causes for short circuits), check all the connectors for dirt, then start putting back the important parts (graphics, 1 stick of RAM, no disk drives). It's often advised to rub gold contacts (for the graphics and RAM) with rubber to clear any static from them, although I tend to skip that step). Then I try powering it on again (with only the minimum hardware to see if it works). Depending on the symptoms after that step (e.g. if the fans spin slightly longer than before), I try other stuff (that's a bit too vague to list in the forums).

    The most reliable way to test things is to have a spare computer to trial each of the parts (power supply, graphics, RAM, disk drives) and narrow down the cause of the problem. The PSU is the most obvious place to look first (a weak 12V rail can cause all kinds of hell in a computer), whilst the Motherboard is the most common part to fail whilst displaying this kind of symptom. If the motherboard's power phasing fails, replacement is the only option. If it's just a short circuit, then grounding the motherbaord (to clear the static electromagnetic field) and cleaning it should fix it. If it's the CPU, it's more annoying to determine (you'd have to try putting a different CPU in to test - I don't know any other way), so you might aswell just replace the motherboard and maybe get a new CPU to go with it.

    Final comments I'll make - computers have a life expectancy relative to the quality of parts. Budget motherboards tend to last 8 months to 2 years. Budget power supplies tend to have 12V rails that deteriorate over time and will probably explode if it takes any more than 70% load. Budget cases tend to be bad at cooling the system and reduces the lifespan of every component by half (or more in the rare case of a high-powered system being put in a budget case). Non-Seagate HDDs tend to last 2-8 years (usually at least 5 years). No guarantees for any Seagate HDD - I don't know any that still works for me, my friends or my clients (the people who pay me to fix their computers).
     
  3. markyboy77
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    Newcomer markyboy77 Member

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    thanks for the great reply

    the green light thats on is on the PSU its self on the back of the tower , its right underneith where i put my power cable into the back of the tower , no fans or nothing come on , i unplugged everything graphix card tv card mouse keyboard and treied it , also reset the bios and took out batter,

    strange thing is that the HP site says that the green solid lihght on the PSU means that the PSU is ok [​IMG]

    aww welll

    its weird the pc was running amazing and my electricicy just ran out like it normally does once a month and never had this problem [​IMG]

    but thanks anyways for the great reply its appreciated

    marky
     
  4. Originality

    Member Originality Chibi-neko

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    Just because the PSU transformer is ok (I'm guessing that's what the green light would signify - that it's "live"), doesn't mean the 12V rail is stable (i.e. producing 12V - it could only be producing 10V and cause the system to fail). IIRC, for a system to work the 12V rail has to be within 12V +/- 0.4V.

    Anywho, you can still try calling HP customer support. I kinda doubt they'll have someone competent enough to fix it at the other end, but you may get a nice person who'll offer to pick up the computer and take it to a tech-lab where they have the proper tools to fix it... or just replace the faulty part(s) on warranty, if the warranty still exists. I can't remember when they stopped using AGP outright for graphics... before the ATI HD series maybe...
     
  5. trumpet-205

    Member trumpet-205 Embrace the darkness within

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    I think it is safe to say that hard drive and optical drive are okay, because these thing depends on BIOS.

    It is possible that VRM on your motherboard is busted.

    When you power on the machine, do the fan spin a bit before stop or not at all?
     
  6. markyboy77
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    Newcomer markyboy77 Member

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    no no fans no beeps no noises nothing
     
  7. Originality

    Member Originality Chibi-neko

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    It sounds like it's most likely the PSU itself at fault if the fans don't even budge.
     
  8. westom

    Newcomer westom Newbie

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    First learn some basics. A power supply is only one part of a power system. A power supply is really two different supplies in one. The green light may report one good. Say nothing about the other. Or a power controller (located elsewhere) is not telling that PSU to power on. You could spend reams of money and time swapping parts. Or spend a full minute to obtain numbers. Then the next reply will report what is defective - without speculation or doubt.

    That means a buying or borrowing a multimeter. Nothing can be 'seen' without that meter. A useful answer means you first read numbers from a meter.

    Set the meter to 20 VDC scale. Attach its black lead to the chassis. Locate a purple wire from power supply to motherboard. Touch that wire inside its nylon connector. Read a three digit number. That simple.

    Do this for the purple, green and gray wires both before and when the power switch is pressed. Report those numbers here to have an answer that actually says something useful.

    Repeat these measurements for any one red, orange, and yellow wire only when the power switch is pressed. Those numbers (how they change and stabilize) defines everything in the power 'system'. Plus other computer parts - without doubt. But nobody can reply definitively without those numbers.

    Borrow the meter. Or buy one for maybe £13. Post the numbers. Then those who really know computers can provide something definitive.
     

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