Antec PSU incompatible with older mobo?

[maxro]

Hi,

I have just got a new Antec 330W Truepower PSU, its a RMA replacement as the last one failed after 9 months (bad caps I think)..... currently running a seasonic SS-PS200 PSU, system is very stable and has been for the last 2 years with this psu:

+5v = 4.94
+12 = 12.21 to 12.30 under load
+3.3 = 3.22

Tested with a volt meter, I think thos voltages are ok?

So I decided to give the seasonic psu a rest as its been in service for nearly 6 years now and fit the antec psu. After hooking it up I pushed the power button and all the fans psus, cpus, case etc.. spin and the green RAM LED lights up on the motherboard but the system looks completely dead...no beep...video...nothing.

I pulled the antec psu from the case and gave it the vulcan nerve grip to test the voltages...

+5v = 5.00
+12 = 11.98
+3.3 = 3.30
-12v = -11.98

I tested the antec psu in another system a PII 350Mhz more or less the same result except the cpu fan didnt spin up on the PII.

Any ideas / help much appreciated.

System:
MB: GA-7ZXE Rev 2.1, BIOS Version 7ZXE-FB
DIMM1:
DIMM2: 256MB PC-133
DIMM3:
CPU: AMD Duron 1.3Ghz
#PSU: Antec 330W
AGP1: Nvidia GeForce4 ti4200 128MB
PCI1:
PCI2: Pinnacle PCTV
PCI3:
PCI4: D-Link DE-528 (NIC)
PCI5: SMC EZ Card 10/100 (SMC1255TX) (NIC)
IDE0: 80GB Western Digital Caviar WD800BB
IDE1: 40GB Seagate Barracuda ST340016A
IDE2: Plextor CD-R 8/4/32A PX-W8432T
IDE3: Toshiba DVD ROM SD-M1612
OS: Slackware 9.1 / Windows 2000 Advanced Server (5.00.2195) SP4

 

[Know Nuttin]

it's possible that you have the newer TruePower PSU, which is more +12v oriented for the systems of today. What are the amperage ratings on the TruePower?

 

[maxro]

Thanks, this is whats on the side of the antec psu:

+5v - 30A
+12v - 17A
+3.3v - 28A
-5v - 0.5A
-12v - 1.0A
+5SB - 2.0A

The manual says its a ATX12V form factor power supply, its backward compatible to previous ATX specifications. If your motherboard doesnt support the AUX Power connectors or the +12V power connectors, you can still use this power supply.

 

[Know Nuttin]

that should be more than enough for your setup. Is it possible that something is causing the system to ground out internally?

 

[maxro]

I dont think so, well none that I can see, the case is an antec so it came with good mobo screws, is there anyway to test for grounding.

 

[Know Nuttin]

Remove the components out of the case, and build your setup on a non-conductive surface.

Oh yeah, to the forums.

 

[RJARRRPCGP]

The ATX power connector may not be in all the way. I had that symptom, too, when the power LED is lit, but the motherboard won't turn on.

 

[maxro]

Remove the components out of the case, and build your setup on a non-conductive surface.

Oh yeah, to the forums.

Thank you

If it was grounded would it still work with other PSUs?

 

[maxro]

The ATX power connector may not be in all the way. I had that symptom, too, when the power LED is lit, but the motherboard won't turn on.

I made really sure they were connected even tried wriggling the wires with the power running just in case they were lose.

 

[Know Nuttin]

It's possible. Nothing can really be ruled out, at this moment, unfortunately.

 

[maxro]

It says in the manual the power supply latches into shutdown stage (when over current, over voltage or short circuit protection is working)... which I think means the psu would totally? shutdown if something was grounded.

I think Ill connect it up again and test the voltages under load, is there anything you think I should be looking for?

 

[maxro]

Well I've just tried the antec psu in the PII system again and tested the volts while it was connected:

+5v = 4.91
+12v = 11.98
+3.3v = 3.28

I think there all within the recommended tolerances.

Just checking the POK (power good signal, pin 8 gray wire) which is showing only 0.50v shouldnt that be 5.0v for that?

 

[flamerail]

Those voltages look pretty good, I started having problems with my thermaltake purepower psu died. The 12v ran at 11.4v, 5v at 5.3v and the 3.3v at 3.1v Only thing it did was cause the rig to lockup under load.

 

[maxro]

Well from further investigation I found the problem, it was due to the power good signal which was running at 0.15V from reading the ATX12V power supply design guide it states that the power good signal (PWR_OK pin8 gray wire) should be between 2.4V and 5V.

The effect of a low power good signal on the mobo is to continually reset the CPU to protect it from bad power, however everything else seemed to get power drives,fans,memory,and even the PCI buss as the light on my NIC was on.

As the voltages all looked good to my digital multimeter I thought Id risk connecting pin8 to one of the 3.3V rails to force the mobo to boot, and it booted just fine. However the +5V rails took a sharp dip to 4.71V.

I suspect the psu is giving out bad power something that my DMM might not pick up.

This is the second antec psu I've had...I wont be getting a third one. fool me once shame on you, fool me twice shame on me, fool me three times....

Those voltages look pretty good, I started having problems with my thermaltake purepower psu died. The 12v ran at 11.4v, 5v at 5.3v and the 3.3v at 3.1v Only thing it did was cause the rig to lockup under load.