I have a SmartPower 2.0 450W with Antec Sonata II case.
The power fan sensor cable is unplugged. I touched the cover of the PSU and i found that it's quiet hot . Is that normal ?
Thanks in advnace.

But the PSU fan is keep running at low speed. When i touch the top of the case , i feel extremely hot.

What happens when you plug it in (the power fan sensor cable)? Does the PSU fan run at full speed?

i found the problem to be poor ventilation of the computer cabinet It traps hot air. When i took the sonata case out of the cabinet, the top of the case is warm , the PSU fan is around 1300rpm..

That's part of it, but it puts the blame too much on the case. Any PSU gets warm, even >80% efficiency ones, unless you get all the heat produced by the PSU blown out fast by a very high speed, high airflow fan. Isolating the PSU from the heat of the rest of the components also helps to keep the PSU cooler -- and this is what you did by taking it out of the case. It's exactly the reason for PSU intake vent/ducts -- like in the P180 case and many other DIY iterations here.

I've had this power supply for a year now, and it's worked fine. That is until recently my computer wouldn't turn on. And the power supply makes a repetitive tweet noise when I put the swtich on the on position. I don't think I heard this noise before. Anyway I'm sending it back for repairs. I also found that there where 5 or 6 user reviews on newegg that report the power supply working fine until finally failing after 7, 8, or 9 months.
Maybe there was a bad batch or something. The weird thing is when I forced it to turn on using paper clips to connnect the correct pins on the 24 pin motherboard connector, the power supply was working, suppling power to the fans and case leds.
I put in my friend's power supply and my computer worked fine.
Just curious, but does anyone know what the problem may be?
Anyways, could someone tell me how to check the speed of the fan?
Thanks ^^

My Antec SP 450W failed about 1 month ago. It is about 10-month-old that matchs many NewEgg user reviews. Therefore, if you have a SP 450W or Sonata II case, pay extra attentions to your power supply....

The first thing I noticed is high-pitch noise from my machine. It is not loud by you can hear it especially with the case open. Then, the machine began to fail booting up... the PC will do cold start or reboot as long as you did not switch off (using back switch) or unplug the power cord. After unplug the power cord, the machine won't start for about 20 minutes and then things came back to normal (until next unplug or switch off). It looks like the SP450 has problems in discharge or something....

Since the symptom is very similar to short current, I cannot remember how many times I had disassembled/reassembled my PC during that week (20 minutes is about the time you open the case, take out components and restart your machine....) I probably will never use Antec power supply again.

Did anyone notice that the 12V output from SP450 is quite high (>12.2V)? My new Seasonic S12 power supply reports 11.8V. (Using Asus Porbe II, not accurate but it indicates the differences)

I have an Antec Minuet II case with comes with an Antec Smartpower 2.0 450W PSU (modified, power connector at the other side and one 120mm fan instead of 2x 80mm). Exactly the same unit otherwise.

The first unit was heating up even when the pc was not running, I measured temperature overnight and it rised to about 55°C. on top of the PSU. I asked a new PSU, installed it but it didn't change, again a hot PSU while the PC wasn't even running. After 6 months of plugging out and in the power cable I again asked for a new one, hoping they fixed this issue. Before sending it back to Antec I closely watched between the vent holes of the PSU and I saw clearly a faulty (swollen at the top) capacitor (take a look at www.badcaps.net for more information about the bad capacitors plague).

When waiting on a replacement PSU from Antec I've temporary used an Aopen 300W PSU and this one didn't heat up overnight and it was even more quiet too!. The new PSU from Antec arrived, I installed it and it lasted... about 2 hours... then suddenly black screen and my PC wouldn't turn on again. I replaced it with the Aopen, no problem. Again replaced with the antec, no power. So this one has terminated itself, nice... Again I contacted antec, they asked me to cut the wires from the PSU and take a picture of it so they could send me asap a new one and I didn't have to send the faulty one back.

I received the new PSU, installed it and again... overnight it is heating up to 55°C. I am tired of it and don't trust the smartpower PSU. I replaced it with the Aopen 300W (which can deliver more current on the combined 3.3V and 5V rails: 200W instead of 150W) and since I use an AthlonXP 2500+ (runs at a very safe XP2900+ speed at default voltage on a motherboard with no bad capacitors) which has no use for the extra 12V P4 connector.

I've rerouted the power cable in the case so it can connect to the aopen PSU internally, the fan of the PSU is blowing outward the side of the case so this is good, the only drawback is that the PSU takes 'hot' air from within the case instead of the 'fresh' air from beneath the case...

I'm a bit disappointed that Antec doesn't do something about this powersupply, I'm sure I'm not alone with problems (a friend also had a smartpower 450w in a sonata II case, suddenly his PSU made a strange noise and the pc didn't boot, he replaced it with an antec neotec and is happy with it now).

Since my Minuet II case has a customized Smartpower PSU it's difficult to use a regular PSU (cooling issues/power cable difficulties) but I'm happy with the quiet Aopen PSU (wich does weight a lot more than the Antec by the way). I don't recommend the Smartpower series PSU, stay away of them and if you have one, measure temperature overnight and take a good look inside the PSU to check if you have bad capacitors.

My Antec Smart Power 450W from the bundled Antec Sonata 2 went dead after 11 months. Luckily for the 3 years warranty, I managed to replace it with another new one. I'm just concern what would happen after another year of usuage.

Uh.ohhhh...

My SP2-450 is just on 1 year old with no signs of issues. So this thread has made me slightly nervous.

I really prefer NOT to replace mine anytime soon!

about 3 months ago, my brother got this psu bundled with the sonata case. after reading this thread, i'm a little worried...any news on what antec is doing on their end about this situation?