Two power supplies in two days! (3rd in a year). HELP!!!!

[Rage_3K_Moiz]

If there are any capacitors on the mobo that have holes or have swollen up pretty much, then its ur mobo thats dying(or probably even dead). Or, maybe its the USB port thats causing the problem. I think that u can turn off the power to individual USB ports in Windows XP but I don't know if it actually works or how exactly it's done. If anyone does, please do mention it.

 

[kirock]

I'm an electronics engineering technologist with twenty years of electronic circuit trouble-shooting, repair and design experience and I'm not exactly sure what's going on here. It seems that the USB port continues to light/power on any device plugged into the back USB ports even when the PSU unit is off? There is some capacitors across the output of the PSU 5V rail and on the mobo. How long do the USB devices stay lit when the PSU is off? Is the PSU fan off?

 

[KingCody]

it still could be a PSU problem, it doesn't matter how many PSUs you have tried, the fact is they are all garbage units and are just as bad as the ones before it.

you should never be cheap when it comes to power supplies, it may not be the most expensive part, but it is the most important component in your entire system. the reason being that it effects the performance of everything else in your system (except monitor), and it can fry everything else in your system if it goes.

as pointed out before, the wattage rating on a cheap PSU means nothing because it will never produce what it says under normal circumstances and they have insufficient protection if any at all. they will not produce stable voltage and constant current. the current that they can provide will be mostly on the 3v and 5v rails where it is not needed, the 12v rail is the most important in any modern system and this is where cheap PSUs lack the most.

chances are that you have already spent more money on garbage PSUs than you would have spent on 1 quality unit that would not blow out smoke. quality PSUs have protection that will shut it down before it ever gets to the point of blowing out puffs of smoke. it's because they are cheap pieces of crap that they keep dying on you.

you do not have a power hungry system, you have an average system, any good brand PSU with 350watts or more will be sufficient for your needs. here is a good link on quality power supplies, and they have some in all price ranges.

good luck

 

[nork]

I agree with KingCody. All or most of us found out the hard way about how important a good power supply (ps) is and how it affects the entire system.
But this seems to be an extreme case, 2 blown ps's and one that has been damaged (you did mention a puff of smoke on this 3rd ps). So it seems that third ps is on its way out as well. Somehow i got the feeling that the problem was a mobo to case type of short. This would explain why all 3 ps's would go bad.
But now that doesnt seem to be the cause. Even though a good ps is always the way to go i get the feeling that if it isnt a mobo to case problem then it must either lie with the cpu or the mobo, with the mobo more likely being the culprit.
But KingCody is right about the ps issue so its hard to say for sure.
I sure hope the end findings get posted here as this is a tough one!
One thing i can say is that you can buy a decent ps for $30 to $40 at newegg.com and directron.com is another good place. There is a recent thread where a bunch of us found decent ps's for a person. There was even a good one on sale for $24.99. Its not on sale now but by now another one may be on sale. But if not there are still plenty between $30 and $40. I will go find that thread just to show you.
It could be, in the end, that you will want to start with a known good ps in order to find the actual culprit here.

 

[nork]

Okay, i found the thread:
https://www.techspot.com/vb/topic50676-pg1.html&pp=20

The more i think of this the more i think you are likely going to have to start with a known good ps to get to the bottom of this issue.
One thing i can say is that if you do get a good power supply, all or most of them will also have thermal protection built into them. They will protect your system in the event that perhaps your mobo is faulty or there is some other issue that was missed.
The sad part is that you just cant trust those cheap power supplies.
The people who develop and enforce the standards for these ps's need to re-write the book but thats out of our hands, or so it seems.

 

[Mugsy]

I have the power... unfortunately.

It seems that the USB port continues to light/power on any device plugged into the back USB ports even when the PSU unit is off?

Correct. With the computer shutdown, as long as it is plugged in and the power/toggle switch on the psu is on, so is anything plugged into the back (including the light on my Ethernet port).

I just tried plugging my USB devices into someone else's PC and verified that the LED's are indeed supposed to go off when the computer shuts down.

How long do the USB devices stay lit when the PSU is off? Is the PSU fan off?

Persistent. As long as the psu is plugged in, everything plugged into the back stays lit. The psu goes off when I shutdown (including fan), as does the both fans on the MoBo (one on cpu. One on the chipset). The power LED on the MoBo is always lit when plugged in. That has always been the case.

A visual inspection of the MoBo reveals no swollen capacitors or singe marks. Everything looks dust free and almost new (the board in only a year old).

Any ideas?

 

[KingCody]

many motherboards continue to provide a small amount of power to USB ports even when the PC is shut down. there is not enough power to run the device, but it is enough to keep the LEDs lit up.

I have 2 mobos that do that (Gigabyte GA-7VT600L and ASRock 939Dual-SATA2)

***Also Mugsy, please do not post the same issue twice. you already have this thread going here, and you just started another one in CPU/MOBO forum. I don't believe that it is actually written in the forum rules (although it should be), but it is frowned upon to post multiple threads on the same issue.

 

[Mugsy]

Following leads

many motherboards continue to provide a small amount of power to USB ports even when the PC is shut down.

Since my board only started doing this after this problem occured, it's evidence something has since changed.

***Also Mugsy, please do not post the same issue twice. you already have this thread going here, and you just started another one in CPU/MOBO forum. I don't believe that it is actually written in the forum rules (although it should be), but it is frowned upon to post multiple threads on the same issue.

As I've narrowed down the problem, I felt I'd have better luck reaching the right audience by posting a more refined question in a more appropriate forum.

Originally, I thought this was a power supply problem, so I posted in that forum. As it is now appearing to be a MoBo problem, I've rephrased the question and posted to the more appropriate group.

 

[Mugsy]

Update: Working but not fixed (or is it?)

Since the computer still works as long as I don't connect certain perifs, and I need my computer, I decided to put it back together and just use it as-is until I can stand it no longer and am forced to upgrade.

I started puting everything back together when I noticed that my TV card had a burn-mark on the backside near where I had connected the antenna the last time it overheated. I wiped away the burn-grime, put everything back together, and reconnected just those devices I found to be safe before.

When I shutdown, those LED lit USB devices I mentioned didn't stay on this time. Huh. I've since reconnected by printer (RS-232) without a problem. I will slowly reconnect everything over the course of the next week... TV antenna last.

Let's hope for the best. If the problem is now fixed, damned if I know why. I hate that!

 

[nork]

If the tv card has a burn mark on it, dont you think that might be the source of your problems? Wouldnt it be wise if you dont use that tv card?
Or, where is the burn mark on the card? Was the card still working?
If i could get all my perifs working and leave the tv card out i would be prone to getting a new tv card.

 

[Mugsy]

Unlikely

If the tv card has a burn mark on it, dont you think that might be the source of your problems?

Unlikely, as it most likely occured during testing psu #2 when the only thing I connected was that antenna wire. The power supply was looking for a ground and sent 550watts/20amps surging through that connection. I'm pray the card still works (I haven't tried connecting the cable again).

Or, where is the burn mark on the card? Was the card still working?

Very near where I connected the antenna.

Over the next month, I will gradually try connecting different perifs to see if the problem returns.

 

[nork]

How do you know the power supply was looking for a ground?

I wouldnt take a month to put my extra parts back in. Usually you will know when you install and turn an item on and use it once, reboot a time or 2, use it again and if all is well then go on to the next one.

I would really hesitate to use that tv card again.