PSU doesn't work on different mobo

goodcool

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Mar 20, 2009
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Hi,

I've recently upgraded my motherboard and have what I consider to be a strange problem with my power unit. My power unit DOES work, it powers my old motherboard perfectly (I've treble checked this) When I try it on my new motherboard though it fails to power it up, the CPU, GPU, case and power unit fans all spin so there is obviously some power getting through.

You're probably thinking the PSU isn't powerful enough for the new motherboard, however it's a Antec 650w 57amp, more than enough power for my system. I've tried it with just 1 stick of 1066 DDR2 ram, HD 4830 graphics card and an Intel Q6600 processor on a abit IX38 quad GT motherboard.

The PSU does have all the correct plugs, 20/24pin ATX, 4/8pin ATX, 4 PCIE 6/8 pin, and loads of molex and sata connectors. I know the PSU has more than enough amps and watts for that system at full load, but it wont even boot to bios...

I've also tried an older PSU on the motherboard, 550w, 36amp and it works perfectly (I'm actually running it now to write this) I cant use it long term though as when I put more ram and a better GPU in it wont be powerful enough.

Apart from the make and power output the two PSU only have difference, the Antec PSU that doesn't work is ATX 2.2 where they have removed the -5v pin. Would/could it make any difference? I'm lost as to what to try next... any suggestions?

Thanks in advance. :)
 
I would use the older ps until you upgrade the video card. At 36 amps, it will handle many gpu upgrades. As for the antec, I don't have any advice. I doubt the ps is defective, but you can try rmaing it anyway. Try it on another motherboard if possible. If you purchased it somewhere less than 30 days ago, you may be able to exchange it for another unit. I use ocz, and corsair is also good.
 


Well the Antec does definitely work, I've tried it on a few different motherboards.... and there is no way of getting a rma as it's a few years old now. :/

You say a 36amp psu could handle a better graphics card? Could you give me an example of a graphics card the 36 amp PSU would handle whilst running a Q6600 processor, 6GB 1066mhz ram, 1 hdd, 1 dvd rw, and a few case fans? What would be the best GPU the power unit could run with that system?

Thanks for your help :)
 
Here's one: http://www.amazon.com/Sapphire-Radeon-6850-Video-100315L/dp/B0047ZGIUK/ref=sr_1_2?s=pc&ie=UTF8&qid=1335050997&sr=1-2. If you want to overclock the cpu, you'll definately need a better ps, but at default settings, this one should work fine if you have the right connector on your old ps. Check the newegg photos for a 6 or 8 pin connector requirement for this card. Newegg offered an extra 10% off with promo code, but the link failed.