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New PSU, no boot

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December 18, 2011 3:18:13 PM

I recently bought the SilverStone Strider ST40F-ES because the power supply ( 350W) of my old pc gave up.

When I plug in the 24-pin connector and boot up, everything works ok, the CPU fan starts spinning fine but my usb ports etc don't have any power.
When I connect the required 4-pin power connector in the motherboard and I press the boot button, nothing happens, it is a dead machine.

Why does plugging in the 4-pin connector make my pc fail? And without it, it doesn't function properly.

More about : psu boot

a c 78 B Homebuilt system
a b ) Power supply
December 18, 2011 3:40:21 PM

All PSUs are not the same.

The difference between a good PSU and a bad one is like the difference between night and day and that is for the exact same wattage on the box.

There is a lot of reasons that you could have the problem that you have.

I would like you to take everything out of the case and put your components on a wooden table. Make sure you touch the metal outside of the case early and often while you do this. Then plug only the CPU and RAM into the motherboard and plug the PSU twice into the motherboard and try to turn it on.

If you don't know how to turn the power on without the power button on the front of the case, there are websites and videos online that can teach you how to do it. Just look it up on a search engine if you need to. If you have your motherboard manual handy you can look for the part where it shows you which two pins are for the power button and touch a flat screw driver to both at the same time.
December 18, 2011 4:38:24 PM

Thanks man!

I grounded myself and removed everything, HD, graphics card etc etc...
Except the RAM and CPU, now when I turn on the system with the screwdriver, it has thesame results:
When both 24 and 4 pin are inserted, nothing happens, when just the 24 pin is inserted, the system turns on.

Some additional info: when both are inserted and everything was still connected, only the SATA devices (HD, Optical) worked, inputs like USB, PCI etc didn't.
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a c 78 B Homebuilt system
a b ) Power supply
December 18, 2011 4:43:12 PM

Do you have any spare parts laying around that you could test things with or that you could borrow from somebody?

Also, what happened when the 350 quit working? Did it just never come back on one day or did it go out with a literal bang?
December 18, 2011 4:50:38 PM

My brother tells the screen just went black, the pc shut down and there was a smell of something burnt.
With the old PSU nothing happened, but when he plugged in the PSU of another old pc, it did come alive.
That made him think the PSU was the cause. So we ordered a new one.

I have a recent build here, with corsair TX850 v2 and all recent parts to test something when necessary?
a c 78 B Homebuilt system
a b ) Power supply
December 18, 2011 4:56:05 PM

So he tried an old PSU in the computer and it started up without any problems in the case with everything connected and all that?

Where is that PSU now? Can you try it again?
December 18, 2011 5:04:06 PM

He isn't sure he also did the 4-pin connector, we're gonna go over to his house and test it now ^^
a c 78 B Homebuilt system
a b ) Power supply
December 18, 2011 5:06:11 PM

Let me know how it works out.
December 18, 2011 9:53:56 PM

Turns out the old PSU works, just like the other one and the new one.
Pc "boots" when you only connect 24-pin, 20-pin connector (originally there was only a 20 pin in it.
But as soon as you connect the other 4-pin nothing happens.

So it's not a PSU problem, but a broken motherboard maybe?
a c 78 B Homebuilt system
a b ) Power supply
December 19, 2011 8:33:54 AM

OK, tell me if I am getting this right.

You have a 24 pin connector and a 4 pin connector on your motherboard.

If you plug in the 24 pin without the 4 pin, fans turn on. This performs the same on 3 different PSUs.

If you plug in the 4 pin processor power cable then nothing ever comes on. This performs the same on 3 different PSUs.

If all of those statements are true, then it is either a broken motherboard or a broken processor most likely.

If your processor sockets are the same, could you try his processor in yours and your processor in his? If they aren't the same socket don't try it, though, because you could break one or both by trying it.
December 19, 2011 11:02:56 AM

Yes, those statements are true.

I own a pentium 4, a i5 2500K and the motherboard/CPU that is broken is AM2, so no compatibility there.

I'll probably ditch that AM2 pc and use the HDD for that pentium 4 pc :) 
Now I have 2 back-up PSU's for my pentium 4 pc, lol

December 19, 2011 11:05:27 AM

Also a little PSU related question:

Is it normal that those 3 350W-450W PSU's I have are way more quiet than the Corsair TX850 v2 I have in my gaming rig?
That PSU is the most noisy component of my build. With all casefans plugged out, it remains noisy so I'm sure it's the PSU.
a c 78 B Homebuilt system
a b ) Power supply
December 19, 2011 12:45:58 PM

It really depends on the cooling setup and how much work the PSU fan has to do.

I would need full system specs as well as a description of your cooling setup before I could say anything about that.

If your PSU is top mount, that means all the heat from the PSU goes into the PSU and gets blown out the back of it by the PSU fans. That can potentially be a lot of heat internal to the PSU on a constant basis. Keep in mind that this is in addition to the heat that is normally inside the PSU from its general workings.

I don't know your situation, but I will pretend for the sake of argument that you are using the whole 850w and at 100% load it is 82% efficient. That would mean you were taking ~1037 from the wall. The extra ~187 would turn into heat internal to the PSU.

Add to that 187 with all the heat your graphics card makes, all the heat your CPU makes, and so on (these fans disperse heat, not remove it, so it is still internal to the PC until the PSU can suck it out.

With no fans, the processor and GPU would easily surpass 120c each which is north of 200 degrees Fahrenheit.

The point is, if your PSU is top mounted and it is doing all the work to pull all this heat out, the fan could be forced to work at max all the time to try and keep up. If that happens, the PSU fan will be very loud.

On the other hand, if you have a few systems around that can work just fine on a 350w the heat they throw off inside would be much less and at 82% efficiency at 100% load (assumed) that would be ~427 from the wall and only about 75w (vs previous 187F) that is generated by the PSU itself.

The fans on the 350w could theoretically work a lot less to get rid of the much less potential heat generated.

I hope that gives you a decent idea of the dynamics in play here.

If you want me to give you better info than that I can't do it without knowing the specifics of your situation.

Anyway, if you really are maxing the fan on a top mounted Corsair TX850 then I would suggest getting a different case with a bottom mount PSU setup and fans on the top that draw the heat upwards and out. That would greatly reduce the stress on the PSU fans and probably allow it to work much more quietly.

It is also possible that the PSU fan is flawed somehow which could cause it to be more loud than usual as well. Again, I can't really know this.
a c 122 B Homebuilt system
a c 144 ) Power supply
December 19, 2011 5:07:51 PM

Raiddinn said:
OK, tell me if I am getting this right.

You have a 24 pin connector and a 4 pin connector on your motherboard.

If you plug in the 24 pin without the 4 pin, fans turn on. This performs the same on 3 different PSUs.

If you plug in the 4 pin processor power cable then nothing ever comes on. This performs the same on 3 different PSUs.

If all of those statements are true, then it is either a broken motherboard or a broken processor most likely.

If your processor sockets are the same, could you try his processor in yours and your processor in his? If they aren't the same socket don't try it, though, because you could break one or both by trying it.

More than likely the motherboard. CPU's surprisingly do not fail that often.
December 19, 2011 5:54:01 PM

Well, this is my setup:
Spoiler
Samsung SpinPoint F3 Desktop Class HD103SJ
Cooler Master HAF X
Intel Core i5 2500K @ 3.3 Ghz
Corsair Enthusiast Series TX850 V2
Microsoft Windows 7 Home Premium w/SP1
Sapphire RADEON HD 6950 Dirt3 Edition
Corsair Vengeance - Geheugen - 8 GB
Crucial m4 - Solid state drive - 128 GB
Sony Optiarc AD-7280S
ASRock Z68 Extreme4 Gen3


The PSU is bottom mounted, exhausting from the bottom of the case. The case is on wheels, so enough space to exhaust there. Air coming out is cool/cold.
Here are some temperatures:
GPU: 35 degrees celcius (catalyst control center)
CPU: 34 degrees celcius (coretemp)

Nothing running, just my browser.

When playing graphic intense games (BF3 on max settings) I have no difference in noise. So Idle or at full load, my pc keeps humming like it does..
That's pretty irritating, because when I'm trying to sleep while downloading some files overnight..
Here is a youtube video I made of my first tx850v2: http://www.youtube.com/watch?v=qRWizAhb7rI

I did return my previous tx850 v2 for this reason. But I got a new one with thesame thing?
a c 78 B Homebuilt system
a b ) Power supply
December 19, 2011 6:06:47 PM

Well, it sounds like the PSU isn't overworked.

It is as JSC said, much more likely for it to be a motherboard problem than a CPU problem.

If you are going to start buying new parts, I would start with that.

However, I still think you should attempt to find some computer that you can switch processors with (same socket) if possible.

As for the PSU, maybe that model is just loud. I think it is one of the ones made by Channel Well Technology (CWT) instead of the ones made by Seasonic, so that could have to do with it.
December 19, 2011 6:49:20 PM

I'm not buying anything new for that AM2 computer, I'll just leave it and reuse the parts I can still use somewhere else. :) 

The TX-850 v2 appears to be from Seasonic.
Should I try to replace the PSU again, this time for another type? (it's been over 1 month since I have the replacement, I had exams..)

Which type should I get? I want to play safe now and get a good brand. (which I tought Corsair was)
a c 78 B Homebuilt system
a b ) Power supply
December 19, 2011 7:07:21 PM

Corsair doesn't make their own PSUs, they draw up designs and tell some other maker to build it in bulk.

They primarily use Channel Well Technology and Seasonic as their OEMs.

I am not 100% sure, but I do think the TX850 is a CWT model, not a Seasonic.

Do you have some sort of documentation that says it is from Seasonic?

You can tell if you want by just cracking open the PSU housing. The real manufacturer will almost certainly be spelled out clearly internal to the PSU, probably on a sticker on the fan, but potentially on the PSU's circuit board too.

If you think you can give it back to the store you bought it from and get something else, I wouldn't suggest opening the case and trying to prove one way or the other.

In any event, Corsair is a good brand, generally. I happen to stand behind Seasonic above all the other brands so I would say that CWT drags them down, but tbh CWT is a good enough maker and you don't hear many complaints about the models they have from CWT either.

If you want to trade it in for something else, try an XFX 850w instead. AFAIK, XFX only uses Seasonic as their OEM.
December 19, 2011 7:15:55 PM

Everything I found on the internet points towards seasonic for this one:
http://forums.anandtech.com/archive/index.php/t-2181866...
(BoomerD's reply)

I'm planning to return it, which one should I go for: that XFX 850W or the corsair AX850 ? (I'm gladly paying the 45 euro difference with the TX if that darn thing would just be silent)
a c 78 B Homebuilt system
a b ) Power supply
December 20, 2011 6:36:36 PM

I like the XFX.

I have an XFX 650w bottom mounted in my case and I can barely hear anything coming out of my case even though I have like 8 fans.
!