Can any one tell me if the following readings are correct. The + readings seem to be OK but I do not understand the - readings

+ 3.3V Voltage 3.28 V
+ 5V Voltage 4.89 V
+ 12V Voltage 11.80 V

- 12V Voltage 1.05 V
- 5V Voltage 1.99 V

The readings are from SiSoft Sandra. I also ran Aida32 and came up with similar readings. I have been trying to track down various little faults that keep cropping up, all started with the mouse that refused to move in the horizontal plane unless it was attached to a KVM switch and the other computer was turned on ( didn't work with a USB mouse either). Then the sound went, then the monitor wouldn't come on unless you did a full re-boot 3/4 times (funny enough that started working again this morning), then the odd setting would change, such as forgetting my automatic log ons when the computer starts up, open programmes getting stuck on the task bar when minimised, USB ports not recognising plug and play and other irritating little things that just don't make sense.
I have got so fed up with it that I have bought a new MB and will be installing it next week. I am running XP pro, Athlon 1.7, 256mb DDR and plenty of HDD room as I have recently reformatted and reinstalled XP in the hope that it would sort these problems out, it didn't.
It was only this morning that I seriously considered the PSU as a sort of after thought, everything else seems to be OK including memory. The system is also virus free.
Thanks

Well the rest looked ok but not these:
- 12V Voltage 1.05 V
- 5V Voltage 1.99 V

Yes- The -12 and -5 voltages look really funky- (The other Voltages look within spec)

Can you check the Voltages in bios? It's possible that SiSoft Sandra and Aida32 are playing games with you....(Then again, I suppose something could be up with your PSU- Do you have another one you could try?).

All the strange things happening to your OS though don't seem they would be typically Power Supply related.

How about your System Temps....Everything cool? :cool:

Are you still hooked up to a KVM or was that just the mouse?

Even though you stated the Computer is "virus free", I would still run Adaware, Spybot and maybe even post a HJT log.
Also try some different on-line virus scans......Almost sounds like your OS is somehow possesed. :eek:

Thanks for the reply...........
I have now thoroughly cleaned the PSU by taking the cover off and blowing compressed air through it and installed it along with a new MB. Everything seems to be working OK at the moment and the current -readings are:

-12V = -9.15V
-5V = -4.70

The + rails are slightly lower now, within tolerance apart from the +12V rail which is reading 11.17

Leave alone or get a new PSU ?

Those readings are voltages, not currents (amps).

The PSU is maybe ok for now, but wonder why it was intermittant for those two legs. PSU voltages are seldom exactly at specs for each output, especially due to variances in the method used to measure them. Higher quality PSUs are closer to specs as a rule, low supply voltages can cause components to burn out or can cause system instability.

Cleaning the PSU is a good idea, just be careful not to get too agressive so components don't get knocked loose.

And if it were mine I would replace the PSU.

:)

Originally posted by PrntRhd
[B]Those readings are voltages, not currents (amps).
I think he means "current" as "now" :)

I guess I am awake now, thanks Reid.

:D

test it with a multitester if you can as most motherboard voltage reading are not accurate but dont open it if you dont know what your doing you dont want to get a nasty shock because of the capacitor ;-)

If it doesn't fit get a bigger hammer

Icywolf are you a computer hobbist or a blacksmith ????

i dont know much about electrical stuff. I am thinking to change my PSU which is an ICUTE 420W which many ppl say better throw it away.
Can tell me what does +3.3, +5, +12 means? and those minus ones.

Btw, i went to bios and see the readings.
cpu temp:43C
motherboard: 36C
cpu fan is 2600+

+3.3 = 3.314
+5 = 5
+12 = not stable, 11.90 or 11.96 (once i saw was 11.84)

Is this bad or good?

+12 = not stable, 11.90 or 11.96 (once i saw was 11.84)

Newer CPUs run on the 12 volt, you want that one to be stable.

If your voltages are that much out of spec.....get a new power supply, it will make things better in the long run.

ok. am using a p4 2.4Ghz 533Mhz. I am buying a r9800 pro.
Does the +12V has to always be the same?

Originally posted by Grumper
If it doesn't fit get a bigger hammer

Icywolf are you a computer hobbist or a blacksmith ????

lol its a quote I found really funny because its anti-computer

Voltages going to PC components can be off by as much as 10% with no ill effects. However, the voltage coming out of the PSU shouldn't be off by more than 5%.

PC Power and Cooling makes incredibly expensive PSU's with built-in line conditioning that are guaranteed to be no more than 1-2% variant.

Electricity is a finicky thing. Not only can it be affected by your home's wiring system (thus some PC users actually need a UPC to keep their PC stable), but your PSU and mobo and other components can also dirty the power.

saphlline whats a UPC ? If you mean UPS thats only going to give you power after you lose power, and it will not give you a constant voltage unless it have a voltage regulator attached and its backed up by a generator.

As you said electricty is finicky---acceptable for most Utilities is +or- 5% on your incoming voltage ex: 120 volts is OK to the Utility ,so is 126 volts or 114 volts--so a $35 PS receives these "acceptable" voltages and that same PS might output a crapy rectified voltage to your computer components, then things happen.

As our infastructures age, and our need for constant voltages increases this greates a need for good [reasonable] voltage regulation.

Actually, a UPS does more than just give you power for a few minutes after a power failure. I started using one because I had read that it does smooth out the power supply and that it has better surge protection than regular surge protectors. I was still surprised when I found that my DSL service which had been very unreliable with lots of CRC errors had become stable with very high quality connections. It was an amazing change and clearly directly related to hooking up the UPS... I wouldn't run a desktop computer without one now.......

Yes, sorry, I meant UPS, but a slip of the finger while typing and... :rolleyes:

Most UPS's also have line conditioning built-in. They didn't used to, but now it's becoming more prevalent, which makes me wonder if they aren't finding cheaper ways of doing it.

Yes, I know that crappy PSU's output crappy power, but that's why I said that the voltages coming out of your PSU shouldn't be off by more than 5%. I said nothing about the voltages coming out of your outlet.

As our infastructures age, and our need for constant voltages increases this greates a need for good [reasonable] voltage regulation.Unfortunately, this is all too true. Especially with computer internals because as the voltages decrease, so does the magic 10% mark. 10% of +5V DC is a lot more forgiving than 10% of 1.4V DC! :eek:

Most UPS do give some measure of voltage conditioning. Especially the larger units (those that are made for small office environments). They tend to provide longer time on battery, also.