Is my PSU dying?

[bigblockmatt]

I was playing COD4 the other day and i was getting an alert on my Motherboard monitor about my 3.3v rail. looking at the monitor, it shows the following
+12v = 11.855
+5v = 4.703
+3.3v = 3.088
vcore = 1.312
at a couple points the 3.3 dropped below 3.0 and the alarm went off.

not sure what is good/bad/high/low. It is a pretty old power supply... it is a Antec True 550w. http://www.antec.com/specs/true550_spe.html

[Darkstar]

I have had a bunch of bad PS units from Antec from the 430 to the 550 both the trupower and smartpower units. I would replace it with a Corsair (all i buy now)

[DMB2000uk]

Software readings aren't really very accurate, so if you could find a multimeter and check the power out for real, then you could know for sure.

For example, My Abit uGuru is reading the voltages at; 5v: 5.13, 12v: 12.42 and 3.3v: 3.42.
When I have already measured them with a DMM and they were; 5v: 4.94, 12v: 12.04 and 3.3v: 3.34.

The readings for any PSU should be within these ranges (5% of target rail voltage):
low > rail < high
3.135 > 3.3v < 3.465
4.75 > 5v < 5.25
11.4 > 12v < 12.6

If they aren't then your PSU is failing the ATX spec, and should really be decommissioned. Your components will try to draw more amps when the voltage is too low, and this could harm your kit (hence why your monitor program is set to warn you when the rails drop too low).

Ideally you would want your PSU to be better than the minimum ATX spec, as it allows for a lot of slack. Nearly all decent PSU's are tuned to within 3% of their target rail voltage, which gives the rails at:
low > rail < high
3.201 > 3.3v < 3.399
4.85 > 5v < 5.15
11.64 > 12v < 12.36

Dan

[bigblockmatt]

hmm... ok. I can understand this thing dying, i have had it for a long time ~ 3+ years.

recommendations?

[ibleet]

As Dan suggested, I would get a voltmeter or multimeter and test it before jumping to conclusions. If it turns out that all the voltages are fine, then you know you have a problem elsewhere.

If it turns out that its failing, then replace it with a Corsair 520HX.

[bigblockmatt]

could you link me to a volt meter that you would have in mind? when i think of meter, i think of a volt meter for a car (and i dont see that working too well)

[ibleet]

Sure, Sears has one on sale right now Multimeter for $12.49.

I use one similar to this to test laptops.

[bigblockmatt]

how would i use that? i dont follow how i connect it.

[Zoogle]

I don't know how to directly test the PSU while your computer is loading it (which is the more important measurement) but if you short two of the connectors, you can at least get your PSU to power on. Then its just a task of contacting the measurement lead to each one of the pins and the ground lead to the ground pin. It's rather hard to explain in words so I think the pictures on this HOW TO would be more helpful to you.

http://www.ochardware.com/articles/psuv ... volt2.html

*oh noes, link to hardware site other than LR *

[insanenoodle]

even if its not dying it would be worth it to update your psu just for energy efficiency's sake

[DMB2000uk]

Zoogle; while it is a good guide on where to measure the voltages from, it should be condemned for turning the PSU on with no load, and not mentioning about how having it powered on like this for more than a few seconds can damage your PSU. The PSU wire jump start is a good trick for checking if a PSU powers on, or if something connected to it turns on, but should be left on for only a couple of seconds.

Sorry matt; I meant to reply but obviously got sidetracked and forgot.

This is how you can measure the 5v and 12v when your computer is on. Find a spare molex and jam the DMM's prongs in like this:

First one measures 5v, and the second 12v.

If you have multiple 12v rails, it might be an idea to find out which cables they go to and measure them as well.

Your black prong wire goes back to the COM port on the DMM, and the red wire goes back to the V/Ohm/mA. The dial should be on the DC V side and around 20v is the one to click it to.

As for the 3.3v rail, you have to measure it from the back of the 24pin power connector. With the black DMM pin in the black molex wire (ground) still, use the red pin to prod in the back of the 24pin port in an orange wire bit. Shove it down the side of the wire till it hits the metal contact. This gives you the 3.3 rail.

Its probably a good idea to take 2 sets of readings. One with the PC idling at the desktop, and another maxxed out. A game benchmark or something similar would be ideal. I go over the top and have running; orthos stressprime, ati tool 3dmode, a spybot/virus check while importing a CD into itunes. Pretty hardcore

Dan

[bigblockmatt]

thanks for the great detail!!! I will swing by sears on my way home from work today and pick one up (there is a sears 2 blocks from work.)

even though if the psu is not dying on me, i still should get a new unit regardless. I have always had an antec (with no problems at all). I would like to keep the budget under 80 if possible. what guys think of rosewill? there is one on sale on newegg for 50 bucks (after huge $70) rebate.
http://www.newegg.com/Product/Product.a ... 6817182070

thanks again for the help. looks like i;m gonna have to hit up the google for the 3.3v test (i think i am gonna need some pictoral help)

[DMB2000uk]

There you go. Google would probably be vauge results anyways.

You will probably have to hold the red stick in with a bit of force, as it doesn't tend to make contact with the metal near the bottom if just left to hang in.

Dan

PS. Checked out the review of the PSU on jonnyGURU and there isn't anything major wrong with it, not as stunning as a corsair PSU would be, but for the money it looks to be great bang for the buck.

[bigblockmatt]

current "initial" findings - no load (idle windows)
3.233
1.193
4.78

[DMB2000uk]

I really hope you forgot to type a two there in the "1.193" result.

So far your PSU passes the min ATX spec (dependant on that error).

Dan

[bigblockmatt]

ha, ya it shoujld be 11.93. damn decimal point

[bigblockmatt]

well, ive been playing COD4 for a bit and playing music
the 3.3v is reading 3.22 (rough average) where the onboard moniitor was saying it was dipping below 3.1

question: what does a PSU "tester" test then? I have one of those and plug all the plugs in and it beeps and stuff saying everything is good. what does that test vs. the mutlimeter?

[DMB2000uk]

I would have thought that it too just checks the voltages.

The difference being that it just tells you if the voltage is within the acceptable range (probably the 5% ATX standard), rather than tell you what the actual voltage is.

Told you software was inaccurate didn't I.

Dan