Zalman PSU incompat with am3 ?

[eperdeme]

Hello,

I have been building PC's for many years and I am stumped as to why this is failing to POST.

I have the following PSU which is unable to get the computer to POST.
The PSU works on other motherboards I have tested but will not POST on
this one.

The system turns on and the fans spin but there is no disk activity or
output from the onboard GFX or the pci-x card.

I have connected the 20+4 pin (tried with and without the 4 pin)
Connected the 2x4Pin 12V connectors (tried all combinations of 1 in 1 out, both out, both in, swapped over etc).

I took the motherboard/ram/cpu back to aria, they connected it in to a PSU and turns on fine with same cables connected as me. But with my PSU just refuses to POST. This PSU works fine on my AMD 939 motherboard, which takes the 20+4 pin and 1x4 12V

If I swap the PSU for another one of ATX 2.2 standards and it boots.

Can you tell me why this is? The PSU is;

Zalman ZM600-HP

It is an expensive PSU and a silent one so I would prefer to not replace
it for no valid reason.

CPU: AMD ATHLON II X2 245 AM3 2.9GHz
Motherboard: GA-MA785GT-UD3H(rev. 1.0)
PSU: Zalman ZM600-HP

[mac124]

As daft as it sounds, and looking at the specs of the psu http://www.zalman.co.kr/eng/product/...ad.asp?Idx=196 , your pc maynot be powerful enough for the psu to fire up as it requires minimum loads on several power rails. It is afterall quite a low power pc (as in wattage requirements) with a relatively high power psu.

There is obviously nothing wrong with all of the hardware as you have proven it all works in different set ups so i am struggling to find another explaination??

[eperdeme]

Hello,

Yes I had the same though myself. The ATX 2.2 -> 2.3 specs fixes this problem looking at the technical notes. Doubt I could take the CPU back in replace for a 4x Core one so it would boot, as its not the suppliers fault. It is a real shame .

Tried plugging in 4x hdd's to the rails but seems to not help as I guess they do not spin up as it does not POST.

Very annoying.

[scaryjim]

... it requires minimum loads on several power rails. ...

The PSU only requires a 27W load over those rails though - what I'm curious about is why it needs draw on the 3rd and 4th 12V rails but not the 1st and 2nd! It might be worth checking that you're using the right connectors to pull current off those particular rails (I'd hope your PSU manual will be able to tell you which they are...). Your system should comfortably draw enough power at start up to kick the PSU into action.

[bandsaw]

Just to add to scaryjim's post, the ZM600 has the rail info on the label on the PSU itself so you might not have to dig out the manual.