I'm having a problem with my PC.

My computer specs are:

  • Mobo: Gigabyte GA H81M S2PV
  • Proc: Intel Pentium G3220
  • Ram: 2x8GB 1333MHz Kingston (Passed on Mem86+)
  • PSU: Corsair CX430 III
  • HDD: Seagate ST500xx (Main) and 2 olds
  • VGA: PNY Nvidia GTX550TI 1GB

All componets are 15 months old except for the HDD and the VGA.

When I assembled this rig, it worked perfectly for some months, then a strange thing began to happen, in the morning it would take a lot of time to post, it started hardly noticeable, then day after day it was taking more and more time, approximately 5 months ago it was taking like 5 minutes after turning on just to post. The functioning was normal except for that delay to post. I used to sleep it sometimes and only turn it off at nights. Suddenly though, that delay problem was gone. I didn't change anything it just fixed itself somehow.

Some months ago however, another problem started to happen. The computer wouldn't turn on when 'warm'. Sleep also started working randomly... sometimes it simply wouldn't wake up and I had to turn it off and wait some minutes for it to cool down before turning it on again. At this point I stopped using the sleep function.

Since then I managed to use it almost normally. Rebooting always works and I just keep it on all day long. However, the 'cooldown' time is getting much longer (it surely has nothing to do with heat because I think after 30 mins it won't matter) and sometimes I let it updating or downloading something to auto-shutdown at night, but when I try to turn it on in the morning it won't start. I'm talking about 3-4 hours after it shut down. The worst part is that I have to turn off the power supply switch and then wait all the 'cooldown' time again, which is at the moment approximately 6 hours and increasing. Basically, I can only turn my computer on after it was unplugged for the last 6+ hours.

When I hit the power button, the fans always turn on, but when it's not working, I can hear that they're 'muffled', they don't sound as loud as when it's working properly. I'm so used to this problem that I can say immediately if it's going to work only by hearing the fans noise carefully. If it doesn't boot and I let it on (with the fans running), it won't boot not even after an hour.

I've tried removing it from the case and removing all the components from it (except the proc. and ram) and it still won't work. I'm suspecting the problem is the PSU, because even after removing the rams and even the processor, the mobo won't beep the speaker.

At the moment I have only the psu+mobo+proc+1ram (kb and monitor) on an acrylic surface. The keyboard is USB but I've tried changing the USB port and unplugging it and that didn't make any difference.

I thought it could be the system fan (because I don't have one) but I've tried plugging one and also I've disabled all the safety features (overheat, etc) on the mobo and that didn't make any difference.

The system was never overclocked.

Please note that I don't have the money to buy a new mobo or psu, and I have a multimeter and I'll be happy to test and replace individual components. I hope it's a psu capacitor or something I can easily replace. I don't know where to look nor how to test most components, but I'll be happy to try. I checked all the components thoroughly and I couldn't find anything visibly damaged (expanded capacitors, burnt CIs, etc)

If that's some kind of protective system kicking in (either from mobo or psu), perhaps there's a way to somehow 'bypass' that by hardware.

I've tested the voltages of most wires when it's not booting and they are normal.

If you have any ideas on what could be the problem, please let me know. I really need this PC to do my work and I foresee the day when I'll have to keep it on 24hs. If that happens I'll remove the VGA and the other HDDs in order to minimize the power consumption.

Thank you in advance.

EDIT: Here are the results of the tests of the psu voltages (jumping the green wire to turn it on): All voltages are good with a minimal variation for more and sometimes a variation for less (only observed in 2 red wires in the main mobo plug, which were 4.9-5.0V). The only big difference was the -12 which were outputting -11V, and I don't know if that's normal but there's no -5V wire. The constant 5V (blue) were outputting precisely 5.00V.

  • 1
    This is going to be a difficult one to solve - it does sound like a PSU problem - probably related to a cap. Not a solution by any means, but maybe try measuring the voltages the PSU is outputting to the motherboard. PSU's typically have circuitry in them to prevent restarting to quickly if ther is a short/overload. You might be better off posting this question on electronics.stackexchange.com – davidgo May 24 '15 at 1:43
  • Thank you davidgo. I have tested the voltages (as mentioned in the question) and they are normal. I'm going to wait for more opinions and if more people think it's the PSU I'm surely going to post on electronics. I forgot to mention also that I updated the BIOS recently. Also, I don't understand how some electronic can have a 'memory' of many hours when unplugged. Perhaps a capacitor that takes many hours to discharge. (I also removed the battery from the mobo just in case) EDIT: Also, I think PSU protection won't even turn on the fans... – Alan May 24 '15 at 1:48
  • Hi guys, I don't know if I'm allowed to double-post here so sorry if I'm not, I just wanted to update that if I jump any 5V with the PWR_OK, the system boots normally, but sometimes it will freeze with a blinking cursor, presumably due mobo malfunction because of the voltages not being ready yet; I don't know if it's safe to keep it jumped like that and plug the other components. – Alan May 24 '15 at 3:05
  • Sounds like a bad PSU, since you have to unplug the power to it for things to cool down. Testing this type of PSU problem is slim unless you have skills and a oscilloscope. – Moab May 24 '15 at 11:48
  • "I don't have the money to buy a new mobo or psu" - I'm sorry. I remember being a teenager and having PSUs fail. Symptoms were like this. Worsened over time. Being moneyless ruined my ability to compute back then. Not fun. "I foresee the day when I'll have to keep it on 24hs" - I've had issues like that, which worsened. I foresee a day you'll be able to keep it on zero hours. Worse, a PSU provides lifeblood (known as electricity) for all your other hardware. A bad PSU may cause harm, shortening lifespan of other equipment. Start saving up and replace before you corrupt data. Sorry. – TOOGAM Aug 25 '16 at 3:06

protected by JakeGould Aug 25 '16 at 2:02

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