I need some help with a PSU

PSUs: The source of DC power for all components in the PC & often a big noise source.

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wussboy
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I need some help with a PSU

Post by wussboy » Mon Dec 02, 2002 11:39 am

Hey all. I was wondering if you guys might know the answers to some PSU questions.

My computer has been crashing regularily, and I think the PSU may be at fault. But I'd like to know for sure before I replace it (being strapped for cash).

I turn the computer on and go into my BIOS's PC health screen. It shows the voltages and temperatures.

At the very start, the Vcore is 1.56 and the 12v lead is 11.99 and CPU fan speed is 6182. After a few minutes, the Vcore is 1.41, the 12v lead is 11.88 and the CPU fan speed is 6000 and everything locks up.

Here's my question. Does the Vcore come off the 12v lead? Is 11.88 terminally low for a 12v lead? Is it possible that as a PSU heats up it would loose it's ability to produce adequate 12v power?

It seems like the culprit to me, but I'd like proof before I shell out for that new oh-so-sweet Nexus PSU. Thanks in advance for your help, guys.

Rock on (quietly).

hyum
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Post by hyum » Mon Dec 02, 2002 8:04 pm

for desktop, Vcore is tyically generated from 12V on P4 systems, and from 5V on AMD system or pre-P4 intel systems.

more cases than not, static load regulation of a PS is not a cause of board failures. after all, Vcore is regulated and does not depend on small changes in Vin. however, a better PS can compensate for other faults in the board. that is, rarely is the PS at fault, however, putting in a better supply, though may not fix your root cause of the failure, may mask it so that your system doesn't crash anymore (or less than before).

geeyoff
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Post by geeyoff » Wed Dec 04, 2002 9:41 am

I was having seemingly random crashes on my computer, and they became much more frequent after I upgraded from an ancient to a modern video card. Slightly underclocking the core of my new video card, however, fixed the problem entirely.

Maybe your problem is in no way related, but it doesn't cost anything to try.

--Geeyoff

larrymoencurly
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Post by larrymoencurly » Fri Dec 06, 2002 8:41 pm

Is the regulation of the +12V really that critical for the Vcore when the mobo has its own regulator for it? I've been told that it can put out a good Vcore voltage even only 9V is fed to it.

wussboy
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Post by wussboy » Sat Dec 07, 2002 7:31 am

That is a question I would dearly love to know the answer to. I haven't ordered a PSU yet, and if it's a mobo problem, I don't want to waste my money. Any advice on where I could find that information? Anyone? Bueller?

MikeC
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Post by MikeC » Sat Dec 07, 2002 8:47 am

wussboy --11.88V is perfectly good for a +12V line. That is only a 1% drop. Intel specifies +,-5% voltage regulation or better. Also, the RPM variance is nothing, it's only 3%. It can vary up and down 5% with any fan, it does not stay rock steady.

The info you've provided so far does not point to the PSU. But you have to give us more details on your system to work with!

wussboy
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Post by wussboy » Sat Dec 07, 2002 10:22 am

Thanks Mike. That post was what I needed to hear. So, at least I know it's not the PSU.

I'm not sure what else to say, other than it crashes. I'll leave system specs later. When I turn it on and the computer is cold (off all night), it gets to the desktop and then locks up. If I reboot when it's warm, immediately I get all manner of lock ups immediately (I won't get anywhere near as far as the desktop).

This may be important: I was looking at my mobo and I noticed that 3 of the capacitors (that's the name for the things that look like grain silos, right?) have cracked tops, as in they are closed on top with 4 pieces of metal that are pushed together forming a + sign. Three of them looked like they have experienced pressure from with in and have split along one of the lines of the Plus. Does this indicate bad things? Time for a new mobo?

AMD 800
MSI KT133
256MB PC133 Ram
Geforce 2MX 32mb
Win 98SE
40GB 7200rpm
Soundblaster Live!

Thanks for your help, as always, guys. Cheers!

quokked
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Post by quokked » Sun Dec 08, 2002 7:00 am

wussboy wrote: This may be important: I was looking at my mobo and I noticed that 3 of the capacitors (that's the name for the things that look like grain silos, right?) have cracked tops, as in they are closed on top with 4 pieces of metal that are pushed together forming a + sign. Three of them looked like they have experienced pressure from with in and have split along one of the lines of the Plus. Does this indicate bad things? Time for a new mobo?
not a heathly sign there, sounds to me that those caps have gone kablooey, this is a good thread, http://miataru.computing.net/hardware/w ... /3475.html
u can try replacing those nuked caps on the board....
the 3 caps that have spilt means that they have blown :(, a lot of cap problems have been going round the web lately

wussboy
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Post by wussboy » Sun Dec 08, 2002 11:35 am

Thanks Quokked. I'm not ready to try soldering anything yet, so I just ordered a replacement. I need to take some soldering lessons, though, that's for sure. :) Can you get a book on soldering?

quokked
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Post by quokked » Mon Dec 09, 2002 2:13 am

wussboy wrote:Thanks Quokked. I'm not ready to try soldering anything yet, so I just ordered a replacement. I need to take some soldering lessons, though, that's for sure. :) Can you get a book on soldering?
it's easy to solder, but practice is needed to perfect the technique, I built a few kits before I got good at soldering and get a GOOD soldering iron :)
look up instructions on the web :)

wussboy
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Post by wussboy » Mon Dec 09, 2002 7:38 am

The last thing I tried to solder was a jumper relay on my 5145 C64 floppy drive. I had two and I wanted them to be able to copy disks from one to the other. I kinda missed with my blob of solder and tried to pry it off. Well, some of the circuit came up with it. Wasn't pretty. Since then, I've been a little shy to try it. Of course, that was back in 1984... :)

ez2remember
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Post by ez2remember » Mon Dec 09, 2002 8:17 am

I also get random resets, but I think it's more to do with the temperture of my CPU at 61 degrees idle, +10 degrees or so at maximum load for long periods.

But it is so strange anyway, sometimes I play 3D games and the system is under heavy load, but no it does not reset at all. But sometimes my system is at the coolest point, i.e. just switched on after my computer being off all day, boom a sudden reset once booted.

What is the underlying cause of this? I have heard Athlon XP processors do this from time to time, is this true?

Annyway heres my spec:

AthlonXP 2200+
ASUS A7V8X
256MB PC2100
ATI All-in-wonder 8500DV
60GB Diamondmax D?740x

Here is my crappy cooling system (Will change all this to this after the new year with the latest and greatest)
Very crappy HSF, Zalman CPNS6000
All Noisy Zalman stock fans running at 5v
Noisy 360W PSU that came with the computer

I am going to spend upto £300 ($450, but remember we in the UK pay a lot more for goods, than in the US) after christmas/new year.

Heres what I plan.

Nexus NX-3000 PSU
Thermalight SK-800
3x 80mm Panaflo fans running at 7v and 5v
Seagate Barracuda IV or V (not sure yet), have this placed at the bottom of my case, laying on sound dampening foam.

Is this a good idea, anymore suggestions you would like to add?
Or should I forget this idea and invest the money for watercooling instead?

Please recommend me a VERY QUIET watercooling system I can buy fairly easily.

quokked
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Post by quokked » Tue Dec 10, 2002 12:46 am

ez2remember wrote:Is this a good idea, anymore suggestions you would like to add?
Or should I forget this idea and invest the money for watercooling instead?

Please recommend me a VERY QUIET watercooling system I can buy fairly easily.
most watercooling systems are VERY QUIET, it's just one of the features that water cooling ends up being :)
if u're looking for something like a plug and pray solution something like the swiftech Q power http://www.swiftnets.com/products/FS020.asp#1 might be what u are after

- one suggestion what's your video card HSF setup like? some of them can be really noisy :), maybe consider the Zalman ZM-80A cooler for it :)

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