Failing power supply?

By God Of Mana ยท 14 replies
Sep 21, 2009
  1. I recently ran into some trouble with my Dell Optiplex. Running integrated everything, 2gb ram, no USP attached. I was using it as I would normally, and suddenly the screen shut off (showing the signal lost box on monitor). The fan continued running and the green power light stayed on. I held down the power button to shut it off. (thinking it was another delayed BSOD that occurred due to a faulty bit of page file.
    When I tried to restart the computer, the power light lit up in Orange, I heard the fan accelerate for 5s, and then the computer just shuts off. I realize this has SOME connection with hardware and electricity, I need help please to figure it out. Thanks in advanced,
    God Of Manna

    EDIT: I forgot to mention, a few days before this happened, the internal fan began spinning at max at all times when heavy CPU was in progress. I also wipped off some kind of blue goop off the processor or something (it was under the mesh car-borator looking thing) the day before the fan started going crazy
  2. Tedster

    Tedster Techspot old timer..... Posts: 6,002   +15

    the only way to test a psu is with a tester tool and a multimeter under load. A PSU tester tool is cheap and costs under $15.00
  3. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,443   +38

    The blue stuff you wiped off may have been the thermal paste. Without that, your CPU will overheat and cause a thermal trip, which will shut the entire machine down. Make sure you have a thin coat of TIM on the CPU.
  4. blerina

    blerina TS Rookie

    yeah the stuff you wiped is the paste that should be there. so if you can't buy the tool, try buying the paste. it's really cheap and will do the work. but you should consult someone before you do anything...and don't wipe anything from you PC unless it's dust, because everything there should be there :)
  5. almcneil

    almcneil TS Guru Posts: 1,277

    Yep, this is overheating. The other guys pointed out you probably wiped off some thermal paste. What thermal paste does is make a "thermal contact" between the processor and the heat sink. If there is even a thin layer of air between the two, the heat sink doesn't work and the processor overheats and stops working. There must be a thermal contact between the two at all times. This also explains why your fan went crazy. BIOS monitors the temperature of the processor and adjusts the fan speed according to keep the processor within operating termperature range. When the processor starts to overheat, the BIOS drives up the fan speed.

    -- Andy
  6. God Of Mana

    God Of Mana TechSpot Paladin Topic Starter Posts: 493

    Hmmm, the thermal paste is very hard to get in my country, are there any -just as effective- alternatives? And so if I was just to replace the thermal paste, everything should start working again?

  7. almcneil

    almcneil TS Guru Posts: 1,277

    I don't know what country you live in, but if you can buy computers you should be able to buy thermal paste. If the the store where you bought the computer repairs computers, they must have thermal paste.

    It just sounds like a thermal contact problem so if you put the paste between the processor and the heat sink, this should solv the problem.

    -- Andy
  8. God Of Mana

    God Of Mana TechSpot Paladin Topic Starter Posts: 493

    My country does not carry a commercial supply of tech hardware. That is: there is no where that will sell thermal paste alone. You should have to buy an entire workstation to get Sourcing form new egg is nearly senseless as shipping would cost over $150.00 Us for a tube.

    Would any silicone based compound work? I can try to make it in my chem lab, so anyone can lead me to some ingredients? :)
  9. almcneil

    almcneil TS Guru Posts: 1,277


    Where do you live?

    There must be a computer store of some kind that makes repairs. See if they will give you some paste or you can pay them to do it.

    -- Andy
  10. raybay

    raybay TS Evangelist Posts: 7,241   +10

    Which model of Optiplex??? Several Optiplex models have serious problems with failing capacitors... they are becoming rather famous for them. Among the most problematic are Optiplex GX260, GX270, GX280, GX620, SX260, SX270, SX280

    If you have one of these, the capacitors are soldered onto the system board. The look like tiny barrels... anywhere from 7/8 inch to 1 1/2 inches tall and about 3/8 to 1/2 across... look for any brown, black, or rust colored powder around the base, or capacitors that are bulging at the top or along the sides, or are split open.

    If you have any bad ones, wll will have to be replaced... there can be as many as 15 of them... They do not cost much, but it you are not good at soldering, you will need to pay or bribe a good tech who knows how.
  11. raybay

    raybay TS Evangelist Posts: 7,241   +10

    If not the capacitors, we would be happy to mail you some thermal paste. It can be found in flat little plastic or foil pouches that fit in a regular postal envelope. I would be happy to send one as a gift if that is ok with TechSpot.
  12. God Of Mana

    God Of Mana TechSpot Paladin Topic Starter Posts: 493

    @Raybay, Thanks for the offer, but I was a able to source some from a aunt who will be visiting us soon.
    The computer is a GX520, getting and changing some capacitors would not be a problem, but what can be a indecator of failing capacitors?
  13. raybay

    raybay TS Evangelist Posts: 7,241   +10

    First the board / computer stops working properly
    If yo uhave the test equipment, of course, then you test them.
    But mostly it is a visual diagnosis:
    The ones that are trouble are shipped like round barrels, and can be from 3/4 inch to 1 7/8 inches high. The bad ones are usually fourn encircling the cpu assembly, within about six inches of the cpu frame.
    Look for bulging, puffy, or rounded tops on capacitors that were normally straight sided and flat topped.
    Look for split sides.
    Look for a black or brown or rust colored powder leaking out of them.
    You can do a gurgle search for failed capacitors, as several helpful techs have posted the brands and part numbers of the capacitors known to be bad.
    They are limited to a fairly small range of motherboards, and those, too, are posted...
    Along with the ones I posted, there are more failed ones for Dell Dimension, Dell Workstation, Gateway, HP, Sony and perhaps others.
    They are the result of design and assembly problems. Nobody knew they were bad until the boards started to fail... and they fail more frequently if your computer case gets too warm or for too long.
    It took the manufacturers about 1 1/2 years to discover the extent of the problem...and they corrected them under warranty if the computer was still under warranty. We had techs all over the place in Arizona, Colorado, New Mexico, and Utah replacing boards without knowing exactly why.
    The boards were exchanged and the suspect boards were sent back for repair.
    A lot of those defective boards are still being sold on eBay.
  14. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,443   +38

  15. God Of Mana

    God Of Mana TechSpot Paladin Topic Starter Posts: 493

    Nope, all the caps seem to be in order, it must just be a lack of paste then....
    Still trying to source some.
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