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Brand New Power Supply - 3.3v rail out of spec?

Discussion in 'General Hardware' started by serratedauto, Jan 1, 2013.

  1. serratedauto

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    I just picked up a Corsair CX430 430W power supply from newegg for $24.99 after rebate to replace a crappy PSU for my home server that came with the case (the case + PSU was $29.99, the PSU was really loud and only came with 2 SATA connectors).

    Anyway, the new PSU just arrived from newegg and I hooked it up to my Antec PSU tester (multimeter is at home) and it's showing that the 3.3V rail is out of spec by almost 20%. Everything else looks fine, it's just the 3.3V rail that is out of spec. Is this going to cause any issues or should I just RMA this back to Corsair?

    [​IMG]
  2. Frag Maniac

    Frag Maniac

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    Wow, that's really low. The CX430 usually tests very well. The 3.3v VR test at TPU had it dipping at most 3.6%, and averaging more like 3.24%.

    The jonnyGURU test showed very good results too, not wavering much even in the hot box.

    Barring a problem with your tester, which seems unlikely given it's 5 and 12 volt readings, I'd say it looks like you're going to have to RMA it.
  3. sneekypeet

    sneekypeet Unpaid Babysitter Staff Member

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    What does software like AIDA 64 or the motherboard software show, just out of curiosity. Also I would hook up a digital multi-meter and verify the actual voltage. If it is out of spec ( +/- 10%) I would send it back.
  4. newtekie1

    newtekie1 Semi-Retired Folder

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    I second the Digital Multi Meter suggestion.

    Though is there anything in a modern computer that even uses the 3.3v rail?
    Crunching for Team TPU 50 Million points folded for TPU
  5. sneekypeet

    sneekypeet Unpaid Babysitter Staff Member

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    IDk last time I had 3.3V issues was on a DFI Nf4
  6. Jetster

    Jetster

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    Just run it. It will be fine.
  7. Laurijan

    Laurijan

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    I would not trust the tester - measure the voltage with a multimeter.
  8. serratedauto

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    I bought the PSU while I am on vacation so I won't be able to test it until next week. But would the tester really be at fault if it was giving "decent" 12V and 5V readings and low 3.3V readings?
  9. newtekie1

    newtekie1 Semi-Retired Folder

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    Sure, if the 3.3v circuit on the tester is broken somehow. I had a test like that that would consistently give bad 5v readings. It turns out the pin on the tester for reading 5v was oxidized so it always read low. After cleaning the pin with some contact cleaner the readings went back to normal. Never did figure out why just that one pin got oxidized.

    Do you have another PSU that you can test to see what the tester says with another unit?
    Crunching for Team TPU 50 Million points folded for TPU
  10. novatech New Member

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    PSU Corsair 3.3v out of spec

    It should be said we have purchased 11 PSU units from Corsair that all exhibit this issue all voltages are fine except the 3.3 v is reading 2.7v which is way out of spec.

    You are not alone, we are sill trying to get all the defective unit sent back for good ones.
    the CX600 & CX430 as well as others are no longer manufactured by SeaSonic as they used to be in the last year since Corsair is no longer using Seasonic for these unit we have had a rash of returns and out of spec PSU units.

    Generally, supply voltages must be within ±5% of their nominal values at all times. The little-used negative supply voltages, however, have a ±10% tolerance. There is a specification for ripple in a 10 Hz–20 MHz bandwidth:[8]

    Supply [V] Tolerance Range (min. to max.) Ripple (p. to p. max.)
    +5 VDC ±5% (±0.25 V) +4.75 V to +5.25 V 50 mV
    −5 VDC ±10% (±0.50 V) –4.50 V to –5.50 V 50 mV
    +12 VDC ±5% (±0.60 V) +11.40 V to +12.60 V 120 mV
    −12 VDC ±10% (±1.2 V) –10.8 V to –13.2 V 120 mV
    +3.3 VDC ±5% (±0.165 V) +3.135 V to +3.465 V 50 mV
    +5 VSB ±5% (±0.25 V) +4.75 V to +5.25 V 50 mV

    8 ^ a b "ATX Specification Version 2.2". 090503 formfactors.org
    http://en.wikipedia.org/wiki/ATX
  11. Frick

    Frick Fishfaced Nincompoop

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    Software or proper measuring?

    And about software readings: DO NOT TRUST THEM. Seriously. Don't. ATM my 12V line is sitting at 7V, according to software.
  12. de.das.dude

    de.das.dude Pro Indian Modder

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    i had a friend with a cx600, had issues with the 3.3V as well. they replaced his in a day. his was a physical loose connection prob though.

    so might be the same issue. you can use a multimeter to check.
  13. shovenose

    shovenose

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    And that's why you shouldn't buy those unexccusably poor quality Corsair PSU's. Their higher end ones, no complaints, but those new CX units kinda suck.

    But then again with no load and using a useless "PSU Tester" who knows... if the computer works the out of spec 3.3V should fix itself.
  14. Batou1986

    Batou1986

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    yea software measurement is crap
    take one psu build identical systems with different motherboards all of them will report different voltages with the same psu
  15. EarthDog

    EarthDog

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    Software is very unreliable. Use the MM if you have one...Also, spec is 5%... the value must be within 5% of 3.3v. :toast:
  16. novatech New Member

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    This was verified with DMM & with Dedicated PS tester

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