Dodgy PSU, can I RMA this?

[oSkar]

I have bought an Enermax Infiniti 650W PSU from Scan and it appears to be dodgy. Whenever I switch off my PC at the PSU, the next time I power it up I have to clear the CMOS before the system will POST. Initially, I thought my problem was the motherboard, so I posted my thoughts in the abit care forum hoping I would get some good advice to fix the issue, here:

http://forums.hexus.net/abit-care-he...connected.html

I've gone as far as setting up the motherboard with the CPU, Video card and 1 stick of memory on top of a box to make sure that the problem wasn't a case short. I hooked the system up to an older power supply I had spare and everything works fine after a CMOS clear. Unplugging the PSU entirely and then plugging it in again doesn't require a CMOS clear before the system will POST. I hooked up the Enermax Infiniti again and the system won't POST unless I clear the CMOS. It works fine until the PSU is plugged out and plugged in again, then it's back to requiring a CMOS clear to boot up the system.

Will it be possible to get an RMA and a replacement PSU? I'm honestly not sure if the usual testing process is going to pick up this issue as I didn't even notice it myself for a week after building the system. Any advice would be appreciated.

My invoice number is 00E1022721.

[Blitzen]

I doubt this is a PSU fault.

This is the 'IP35 problem' rearing up again.


Flash your BIOS to the most up to date version.
Let the system reboot and all should be well.
It should then only double boot if you switch the PC off at the wall (which no-one should do anyway as it will flat the CMOS battery). <-----Have you replaced your mobo battery?

EDIT - It looks like you have tried some of this already but the symptoms that are showing do not sound PSU related.

[oSkar]

I have flashed the BIOS up to version 14. I didn't go to version 15 because I've heard of people being unhappy with it compared to 14 on the Abit forums and there weren't any applicable fixes in 15.

With the other PSU, it double boots the first time it is powered up and then single boots everytime after that. With the Enermax Infiniti I get the same behaviour, except after the PSU is switched off or disconnected from the wall. After the power is removed completely, the system won't POST unless I clear the CMOS with the power connected. Clearing the CMOS with the power disconnected doesn't help.

I've also had a close look at the PSU. None of the capacitors look damaged but there is a bit of yellow glue covering some of the smaller components which looks cracked so I guess there could be a broken connection somewhere in the PSU.

If the problem isn't PSU related, why would the no-posting problem not happen when I hook up a different PSU that had been working in my previous system for about a year?

[Blitzen]

Have you tried the Inifiniti without unplugging at the wall?

Its hard to tell if its PSU related or not but this is definitely what has been happening, with many different PSUs, using the P35 chipset.

[oSkar]

If I don't unplug the PSU from the wall, but switch off the PSU, I need to clear the CMOS before the system will POST.

If I don't unplug the PSU from the wall and don't switch off the PSU, everything works fine as far as I can tell. The system is stable enough for me to get Vista installed and run 5 minutes of Prime95 without any errors.

I'd rather not have a power supply that forces me to open the case and clear the CMOS to get it started if I go to a LAN.

[Bhavv]

This really doesnt look like a PSU problem, but it is very strange and something that I havnt encountered before.

PSU problems would be random shutdowns, PC completely not starting up (No lights, fans not switching on), and basically just problems with getting power around your system.

If your PC powers on fine and you have problems booting due to bios, that is usually due to incorrect or incompatible hardware settings.

[Blitzen]

If I don't unplug the PSU from the wall, but switch off the PSU, I need to clear the CMOS before the system will POST.

If I don't unplug the PSU from the wall and don't switch off the PSU, everything works fine as far as I can tell. The system is stable enough for me to get Vista installed and run 5 minutes of Prime95 without any errors.

I'd rather not have a power supply that forces me to open the case and clear the CMOS to get it started if I go to a LAN.

From what you have said there, although with that PSU it displays these problems, i still dont think its a PSU issue.
Its a P35 chipset/bios issue.

You shouldnt have to unplug a PC from the wall after use. This is a bios fault once the battery on the CMOS takes over almost certainly.

[Koolpc]

Looks like a motherboard issue to me.

[Andydigital]

How do you equate it to be a motherboard problem if the older PSU doesn't exhibit the problem but the newer one does. Unless the older PSU holds a residual current great enough and long enough to keep the bios settings in place. Try unplugging the older PSU for about 10 minutes before testing again to rule out this theory.

[IAmATeaf]

Do you have any USB devices plugged in? Try unplugging them all and disabling any USB settings in the BIOS. Not an Abit problem that I've heard of but Gigabyte mobos have a similar problem and this seems to fix it, worth a try I suppose.

[oSkar]

Thanks for the advice, everyone.

I tried unplugging the old PSU and leaving it off for 30 minutes, then plugging it in again. The motherboard booted up fine. I've also tried swapping the motherboard battery with an identical battery from a motherboard I've been using for about a year and it makes no difference when using the Enermax Infiniti.

I have the system set up on top of a cardboard box with nothing plugged in except an 8800 GTS, 1 DIMM, Q6600 and Tuniq Tower so there's not much chance of this being an issue with power draw and no chance of it being caused by a short with the case.

I've also had a close look at the Enermax Infiniti and it looks like there's some internal damage to some of the coils at the back of the unit. They're bent to the side a bit and the glue around the base of one of the coils has cracked so it's obvious that they weren't manufactured that way.

I know this is a very strange issue and initially I was convinced that this must be a motherboard issue as well, but I think I've done everything possible to work out the cause apart from plugging the Enermax Infiniti into an older motherboard to see if I get the same problem. Now that I've noticed some physical damage on the PSU, I'd rather not try it in case I fry the old motherboard.

[Bhavv]

Ok, I think its the PSU then. Have you emailed scan?

[oSkar]

I called their Tech Support line and they asked me to test the power supply in another system to confirm that there was definitely a problem with it. I plugged it into an Athlon 4000/nForce 4 system we had at work and I confirmed that the system won't boot with the PSU plugged in. I did find that the system would boot without the 12V 4-pin connector, however.

I called Scan again and they gave me an RMA Number and have arranged for a courier to come and pick the system up tomorrow so they can get it and test it themselves.