Question "Power good" voltage?

therschbach

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Sep 8, 2007
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I have an Antec TruePower Trio 650, and have had it many years. I just put together a new build and upon applying power to the system, all I get is a blinking led from the mobo. I put the old build back together and the old mobo is now doing the same thing, the onboard power led is blinking. No fan, no beep, nothing else except for the blink led. (Both mobos are Gigabyte fwiw)

So I voltage test the psu...

Orange 3.34
Red 5.09
Purple 5.07
Yellow 12.34
Blue -12.18
Gray .1

All voltages are stable. However, from what I am reading, the Gray (power good) pin should be outputting 5 volts if all the internal tests pass. So I'm assuming from my test results, that for some reason the psu isn't giving the power good signal so the mobo isn't even going to try to post, right? I'm not sure why it wouldn't power good signal if all the voltages test good?

I have another psu coming in a few days , and a psu tester, but I'm trying to make sure I'm not missing anything.
 

therschbach

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Sep 8, 2007
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The PSU is on what would be it's 3 build I think.... probably around 5 years old.

OLD SYSTEM (which worked fine until I disassembled it)
4790K, mildly oc'd
GA z97x UD5H
Gskill Ripsawz 2400 32gb 4x8
3tb hdd, 500mb ssd
1070 gtx
Cooler Master Master Case Pro 5 (LOVE This case!!!)

NEW SYSTEM
9700k
z390 Aorus Pro
Ballistix 3200 64gbb 4x16
same hdd, same ssd, +m2 drive
2080
Cooler Master Master Case Pro 5 (LOVE This case!!!)

I mean, nothing is plugged in when I'm testing it so I'm not sure why any of the other components matters. It does the same thing with nothing plugged into it, no cpu, no ram, on a box, etc...
 
Last edited:

sdedu77

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Dec 9, 2018
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I know I'm late, but hope this is still relevant.
Those voltages are normal, except for the gray (Power Good). I have a really old (13 years this year) PSU, but voltages are still within limits and the original system still boots and runs fine. I measured with a multimeter both 5v (red) and PG (gray) and the voltages are both the same (about 5.12v). That unit might be faulty.
 
Mar 5, 2020
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I just bumped into this forum and read your issues, while I have been looking at how to convert a computer power supply to a general power supply unit. In particular, I have been searching for the reason why a dummy load of resistor is necessary when the power supply unit is on but not loaded with any devices.

My observation is, when the power supply unit is standing alone, i.e. it is not loaded with anything (e.g. a dummy resistor, say 5w 10ohm, or a hard drive, motherboard, etc.), the power-good connector (the gray connector, in your case) will not measure 5v, instead it gives nearly zero voltage.

In fact, that signals the outputs are not stable yet, even though I can still measure the corresponding voltages from all the colored connectors, except for the power-good one.

Hope this information is helpful to you.