5v output... I KNOW I KNOW

[supraway]

I have the Enermax 431 watt Whisper power supply. I saw all the posts back in the day about low 5v output, and didn't listen to anybody about staying away from this particular power supply. Well, now I'm regretting it. My 5v has been going downhill since the day I bought it. Started at 5.01, 2 months later, 4.93, another 2 months later, 4.86, and now, ~4.75. I haven't had any stability issues whatsoever (computer runs 24/7, and has only crashed once or twice in 2 months), but I am one of the tweaker types who worries about things before they become an issue. I have heard of people taking apart the PSU to replace parts to resolve the issue, and was wondering if anybody has a link to an explanation of the procedure.

BTW, I already read the post by Hoot, and the 5v is low coming from the PSU, not the motherboard.

[supraway]

Oh geez, I just looked again... it looks as if it has been dropping in the last few days, too. MBM5 is now reporting my 5v to be 4.70. What am I going to do?

* I just looked again... it is actually fluctuating between 4.70 and 4.76 *

[RangerJoe]

check in your bios, i have that psu, and mine has never gone below 5.03...no matter what speed

[Fink]

Do Not Trust MBM or BIOS for Voltage Monitoring!

Check your voltages with a mulitmeter.

All my VIA boards report low +5V and rails (4.86V) but the multimeter reads 5.06V. Even during boot (this is a SCSI system-3 10K drives) the voltage only varies 0.04V.

[eobard]

Yeah I wouldn't trust MBM at all. I gave it a try in the past and got some unbelieveable readings from it.

[ButcherUK]

Multimeter on the molex connectors will read different to the motherboard sensors. Which is right? both! You loose voltage going to the motherboard.
One of the main problems though with most power supplies including enermax is that the 5 and 12v lines aren't regulated at all. Only the 3.3 is and the others are based off this, this causes a lot of problems with low 5V and high 12v etc.

[killem1x1]

These guys are right on the money. I don't use mbm for anything except double-checking my temps, the cpu display is almost always wrong, as well as the voltage. As far as I know the only true device is my trusty fluke (meter), it has never let me down.

[rogerdugans]

I use mbm for relative monitoring, ie: if I have been running at an indicated 38c temp and it changes: I need to go look at someting in my cooling setup. Same with the voltages- I don't trust them to be accurate, but they do usually run consistent. If some thing changes more than a small amount, a few tenths, then I'll take a look with a multimeter. Usually, if mbm shows a change then the actual reading is also different.....but not always.

And voltages at the psu and on the mobo are not the same, in my experience: close, but different.

I test a psu when I first install it and write my readings down on the side, for future reference: helps to isolate a bad psu if I have trouble in the future.

The only thing I can say about the drop now is: check power at the molex, and keep an eye on it: if it changes again in mbm, check the molex and see if that is the same. If the psu has NOT changed, maybe the atx connection to the mobo is loose?

[Hoot]

Core MBM=1.79 / Fluke=1.76 Error=1.7%
+5V MBM=5.18 / Fluke=5.10 Error=1.6%
+12V MBM=12.25 / Fluke=12.10 Error=1.3%
Vi/o MBM=3.47 / Fluke=3.43 Error=1.3%

Meter Accuracy +/- .3%

In defense of MBM, these are not horrendous error factors. The voltage sensing IC is not a Lab grade device. Don't expect Lab Grade accuracy.

Hoot

[supraway]

Fixed it. I originally thought the 5v coming from the PSU was low, but I unplugged the ATX connector from my motherboard, and picked at the inside pins (I dunno what to call them), making sure they were tight, cleaned them, and put the connection back together. My voltage went from 4.66 to 4.88. I haven't checked BIOS yet, but I'm assuming 4.88 is about what I'm at, and is a respectable voltage.

Thanks, Hoot, you were actually correct about the ATX connector, this was the fault, and I hope you all pass this information on.

[eobard]

Originally posted by Hoot
Core MBM=1.79 / Fluke=1.76 Error=1.7%
+5V MBM=5.18 / Fluke=5.10 Error=1.6%
+12V MBM=12.25 / Fluke=12.10 Error=1.3%
Vi/o MBM=3.47 / Fluke=3.43 Error=1.3%

Meter Accuracy +/- .3%

In defense of MBM, these are not horrendous error factors. The voltage sensing IC is not a Lab grade device. Don't expect Lab Grade accuracy.

Hoot

I use Probe, it never gave me any real problems, not even the 10c core descrepancy that most Probe users experience. When I gave the latest MBM a try my readings in both MBM and Probe went berserk. Suddenly my temps were reporting 25c higher and my voltages went nuts too, I can't remember the voltage ratings I got but it was really stupid, something like 300 volts on the 5v line. I de-installed MBM and the problems were still there in Probe. I had to clear my bios, power down and leave the system off for 10 minutes to get things to reset. I'm not saying Probe is flawless or that MBM will be horrible for everyone but it sure was horrible for me!