Faulty PSU? 5.4v on 5v rail

NF7-S

NF7-S

NF7-S

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As title really, 2nd hand build for my son...all seemed fine 890until a reboot during thw Win7 installation when it just wouldn't reboot.

Long story short it seems fine when cool but I guess something is overheating (eventually) and then causing booting issues.

The system is a Q6600 + HD4890 PSU Onyx (TBC) 750W (it's a good quality one, but old now)

I bought a PSU tester which is warning me the 5v rail is @ 5.4v.

I've put 2+2 together and think the 5.4v is just took much for something that's slowly cooking but before I splash £40 on a replacement thought I'd ask for some expert advice.

Also, if it is the PSU do folk think 450W will be enough if it's a half-decent brand?

However, I'm open to suggestions...cheaper the better (but obviously not cheap rubbish if you know what I mean! :D)

Thanks in advance :)
 
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700W is a bit of an over kill for that system, I'd personally be looking at 500W

Going for less power means you can get a decent brand, dont get a cheapy one as you regret it later on.

@jamesfreddie - it's 5% for all positive rails, 10% for negative rails so he is out of spec.
 
jamesfreddie said:
5.4V is still whithin ATX specs.

You have a 10% tolarance on the rails.

So a max of 5.5V
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±5%, 10% tolerances are for negative voltages. 5.4v is out of spec, however without knowing how the psu handles loading etc, theres no way to say when the other lines have a load that the 5v dosen't regulate itself properly, best way to test is when its actually hooked up to a motherboard with a dmm. Cannot say i have heard of that brand of psu.
 
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Well it is out of spec, 10% is for -5v not +5v whose top tolerance is 5.25v @ 5% . However like i said, best to check when the other rails have a load on them as well (i.e connected to board) as an unloaded psu might produce weird voltage readings.
 
What PSU tester? Is it under load at the time? Has the PSU tester been calibrated (I bet the specs for it also specify +/- 10% accuracy :D)
 
PhillyDee said:
What PSU tester? Is it under load at the time? Has the PSU tester been calibrated (I bet the specs for it also specify +/- 10% accuracy :D)
Click to expand...

lol tell me about it, some people actually think their software voltage readings are spot on too :D All a psu tester can do in my book is verify the blasted thing turns on.
 
Whats the exact brand and model of your power supply? That psu tester is just random tat to be treated as a little curiosity and toy, hardly anything to be taken seriously.
 
That PSU tester accuracy is +/-0.1V so on the face of it your PSU is out of spec, but personally I would still look to test with a multimeter.
 
Justintime said:
Whats the exact brand and model of your power supply? That psu tester is just random tat to be treated as a little curiosity and toy, hardly anything to be taken seriously.
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I'll take the thing back then...£25 at Maplins, not like I went for the really cheap option!

The PSU is a Oryxx OX750-SD...odd, I'm sure I did a search and read good reviews, it certainly looks quality - you know, the black webbing stuff and fancy plugs :confused:

does the one I linked to look any good for what I need?
 
Well i did indeed come across a system with an Oryxx Titan i think and it suffered from random shutdowns with a HD4870, new Seasonic psu sorted it. Never bothered to look at the psu as it struck me as a generic unit and it seems Oryxx are dead as a company, now i'd like to see who oems their psus as it seems they were sold as a high end brand, which may be true or a complete farce, no idea.

http://www.overclockers.co.uk/showproduct.php?prodid=CA-007-XF&groupid=701&catid=123&subcat=1497 This might be a better choice than the OCZ.

Have you tested your RAM and checked temps etc.. btw?
 
Found the specs for your psu
+5V - 36A
+5VSB - 2A
+12V1 - 18A
+12V2 - 21A
-12V - 0.8A
+3.3V - 35A

As far as modern specifications are concerned that is a 468W power supply as it uses a very early 3.3v/5v heavy design, i,e ATX 1.x not 2.x and is no good really for modern systems. I'm guessing its likely a generic pos.
 
cheers guys - I've had another look and altho it is quite nice looking I was getting the plugs confused with the other PC :o

I've whipped the 650W corsair from my other PC and I'll see how that goes...if it's stable then I guess it's new PSU time for sure.

is that PSU really worth the extra £20 for just 50W more?
 
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