GA-P67A-UD3-B3: won't power up

[robig2]

Hi,

I`ve just bought the GA-P67A-UD3-B3 with a core i5 2500k. Plugged everything in to find that it won't power up at all (not even fans).
After trying several things I narrowed the problem down to the PSU. Plugged in a thermaltek lightpower 450w PSU and mobo started when plugging my enermax liberty 620w it won't -> sound like the problem... however when i connect the 620w to my older comp (DFI bloodiron p45 with c2d e6400 @ 3.5ghz) it work perfectly!

I`ve looked at specifications for both the psu and the board and couldn't find a single thing that would indicate they are not compatible. Can anyone help me with this please?

[Dark Mantis]

Hi and welcome to the Gigabyte forum.

The 450W Thermaltake  is a bit underpowered to run your system but obviously has enough power to work for a while. It could be that the Enermax is faulty but works well enough to power your older system. Also the new systems are a bit more fussy when it comes to PSUs. Is the Enermax a multirail 12v output ?

[robig2]

thanks for the quick reply.
yes, the enermax has dual +12v rails of 22amps each.
you can see its specifications here:
http://www.bjorn3d.com/articles/Enermax_Liberty_ELT620AWT_620W_Power_Supply_Review/863.html

[Dark Mantis]

Can you list your system components please ?

[robig2]

CPU: core i5 2500k
board:  GA-P67A-UD3-B3
memory: 2x4gb corsair CMZ4GX3M1A1600C9‎
GPU: sapphire toxic 4870
PSU: enermax liberty 620w

Anyway, stripped it of all parts but the cpu so I guess the rest doesn't matter much.

[Dark Mantis]

Have you checked the cable connections on the Enermax to make sure they are all solid ?

I don't think the smaller PSU is really man enough for your system though.

I take it that you have connected all the power cables to the motherboard, the 8pin 12v EATX, the 24 pin ?

[robig2]

yes, both cables 24pin & 8pin connected.
I tested the 8 pin cable using a multimeter and found that all 4 +12 line indeed have +12v on them. for the main cable, i tested it with a thermaltek psu tester which indicates that all voltage types are present.

I guess I can try shorting the 16th pin and testing voltage output for each pin.

About the 450w, I have no intention of even connecting it with my GPU. I`ve tried connecting a strong GPU with a weak PSU once and it fried the GPU... so the 450w was just to make sure the mobo is not defective and that it can power up.

At this point I just want to get the mobo power up.

[Dark Mantis]

Yes I didn't think you were intending to actually use the 450w but thought I had better mention it anyway.

No I don't think there is any point testing the 650w any further in that respect as you said it ran your old system ok so obviously all the voltages are there.

I have quite often had a problem on the forum here with multi rail 12v PSUs but that is normally with the GPU installed as they use quite a lot of power on bootup. However yours isn't connected you say so that can't be the problem with this one.

To be honest it is a tough one. The board and CPU etc are obviously ok as they booted with the 450 so that only really leaves one conclusion that the 650 Enermax is faulty somewhere.

[robig2]

So as far as you know there shouldn't be any compatibility issues between the board and the psu?
btw, I`ve tested the psu with a h67 board as well with no luck.

[Dark Mantis]

That pretty much confirms that the PSU is faulty then. No as far as I am aware the PSU and board should work together.

[robig2]

I tested the individual lines on the 24pin and they all seem ok - although the 3.3v was giving 2.97v (all of them).
I`m going to test the 450w 24pin to see how much the 3.3v lines give there - if this is too low it may explain whats wrong.

[robig2]

The 450w give 3.4v - thats a big difference! since it should be at +/-5% and my 620w give 2.97v which is exactly 10%

I guess I`ll have to get a new one and let it work with my old rig as long as it can.
Thanks for your help!!

[Dark Mantis]

You are most welcome and I am glad that you managed to actually prove my theory of the problem. At least you found the issue before it went really bad and took out other components at the same time which is quite common.

[robig2]

new development: I rebuilt my old rig and as before, everything worked. I looked at the bios at the voltage report for the 3.3v rail and it says 3.34v

I think I may have proven the existance of gremlins!

[Dark Mantis]

More likely the existance of a broken wire or bad connection