Antec Phantom 350 Shut Down - too much load? Need Fanless...

marvin-miller · Post by **marvin-miller** » Thu Jul 27, 2006 11:25 pm

Hi Folks;

I have an Antec P180 and after about a year I chose to replace my cheapy 320 watt fanned power supply with the awesome Antec Phantom 350.

I was really excited because of it's efficiency and silence. Thing is though, once I installed it my workstation would not completely boot.

Once the O/S was almost finished starting up it would access the CD drives (to pre-read the disks, I guess) and at that point the Phantom 350 would immediately shut down.

This happened each time I started the system. The Phantom 350 was cooled by the large fan in the P180's lower plenum - really, you couldn't ask for better cooling for a fanless power supply.

The conclusion I came down to is that the power supply was shutting itself off because the draw was more then 350 watts. I read that the Antec is very strict about over-loads and the like. System specs are;

Athlon XP 3000+
(7) 15K SCSI Drives
(2) Optical Drives
(1) Dual Channel Ultra-160 RAID Controller
(1) ATI Radeon 9600XT
(3) Large cooling Fans (P180 size)
(2.5) Gigs of RAM

The existing power supply is a StarTech 320 watt unit;
http://www.dealtime.com/xPF-StarTech_co ... onnector_s

and it's worked flawlessly for the last year - certainly it's outperforming the Antec Phantom 350.

The reason I felt an upgrade to an Antec 350 was warranted was because when I took the StarTech unit apart there was some burning evident on one part of the unit. I thought maybe it was going to go south plus I am wanting to add another (2) SCSI drives at some point and I thought maybe I was stretching it with a 320 watt power supply.

What are the chances I just got a dud Phantom 350?
Can someone recommend a different high quality fanless unit that would fit into the Antec P180's plenum?

Thanks!
Marvin

jaganath · Post by **jaganath** » Fri Jul 28, 2006 1:08 am

The conclusion I came down to is that the power supply was shutting itself off because the draw was more then 350 watts.

I think it's unlikely you are drawing more than 350W. More likely is that the 7 HDD's + 2 optical drives is triggering the overcurrent protection (see the FAQ about dual 12V rails and current limiters).

SnooP · Post by **SnooP** » Fri Jul 28, 2006 2:17 am

Nope don't thinks it that. That might make sense if it shut down when the hard drives are spinning up (ie straight away). Hard drives draw as much as 2A when spinning up, decreasing to around 500mA once they're running at full speed. so startup draw = 14A, draw when cdrom spins up = 7A perhaps. Perhaps the cdrom is a bit weird and surging a lot more than it should, try each cdrom individually with other unplugged.

Chrissicom · Post by **Chrissicom** » Fri Jul 28, 2006 2:44 am

Athlon XP 3000+
(7) 15K SCSI Drives
(2) Optical Drives
(1) Dual Channel Ultra-160 RAID Controller
(1) ATI Radeon 9600XT
(3) Large cooling Fans (P180 size)
(2.5) Gigs of RAM

<<< Ouch 7 15K SCSI Drives??? I think they draw at least 250 Watts alone during boot!! When you boot your computer especially hard disks require much more power than usually because the motor is started. With the rest of your components you can easily go way above 350 Watts peak during booting in my opinion. The Antec Phantom 350 is definitely not suitable for your system.

A 15K SCSI Drive needs about 12W in idle that would be around 84 Watts alone for your hard disks when you are doing nothing.

The startup power requirement for a 15K SCSI disk should be around ~2.5A on the 12V rail / disk and ~0.8A on the 5V rail / disk.

That is 17.5A on the 12V rail and 5.6A on the 5V rail. Your Antec PSU offers only 16A on the corresponding 12V2 line. As I said your PSU can never ever boot that system of yours.

SnooP · Post by **SnooP** » Fri Jul 28, 2006 3:19 am

yes but OP said

Once the O/S was almost finished starting up it would access the CD drives (to pre-read the disks, I guess) and at that point the Phantom 350 would immediately shut down.

Indicating scsi hard drives aren't the problem since they've already spun up long before its into windows.

marvin-miller · Post by **marvin-miller** » Fri Jul 28, 2006 7:11 am

Hi guys;

Thanks for the replies

The hard drives are Seagate Cheetahs and they are remarkably efficient. The Phantom 350 had no problems with starting up the drives etc - what happened was that once the O/S was loaded (log-on screen) the startup process then accesses both CD-ROM's (I suspect to pre-load the directories).

As soon as that happens the power supply shut down. It was as consistant as can be - it would never complete the boot process and it always died in the same spot and as soon and you saw the lights come on on the optical drives it shut off.

Keep in mind, that would probably represent the highest (or near) highest load on the system. All 7 drives are active loading up the O/S (RAID 5 array) and then the O/S is looking at the optical and floppy drive.

What surprises me is that the startech 320 watt PS has been working for more then a year in this system. I really thought that a 350 watt unit would give it some breathing room.

Here's the electrical specs on the drives;

Typical Current (12VDC +/- 5%) 0.79 amps
Startup Current (12VDC +/- 5%) 0.99 amps
Typical Current (5VDC +/- 5%) 0.88 amps
Startup Current (5VDC +/- 5%) 0.93 amps
Power
Idle Power (typ) 10.3 watts

Thanks;
Marvin

jaganath · Post by **jaganath** » Fri Jul 28, 2006 7:45 am

I'll ask the obvious question; have you tried disconnecting the optical drives?

marvin-miller · Post by **marvin-miller** » Fri Jul 28, 2006 7:56 am

Hi jaganath;

I didn't try disconnecting them - I just assumed the power needs of the system were too high for the supply and that it was shutting down because of this.

That led me to think that the reason the old power supply has no problems with the system would be because it has no sophisticated circuitry and just continues making power as needed - even if it's beyond the 320 watt rating.

I don't know a lot about power supplies but that seemed to make sense - as a result I returned the Phantom 350.

I still want to add a couple of drives at some point so I need some scalability as far as the power supply goes.

At this point it seems to be a question of what power supply should I install in my P180 case? I would prefer a fanless one and one that is very efficient. I don't know if the Phantom 500 will fit or not but I'm guessing it will be able to handle the power requirements of the workstation. Really, based on my experience with the StarChoice 320 watt supply I figured just about any power supply would be able to do it

cmthomson · Post by **cmthomson** » Fri Jul 28, 2006 10:36 am

It has been a while since I worked with SCSI drives, but my recollection is that they spin up sequentially to avoid a big spike at power on. So creating a RAID file system could indeed represent maximum 12V draw as all the disks seek and write at about the same time.

marvin-miller · Post by **marvin-miller** » Fri Jul 28, 2006 2:19 pm

Agreed. In fact, when the problem occurs is as the O/S is completing loading. So the 7 drives are spinning together and then it hits the optical drives and then shuts down.

I think we've cased the issue - that being the Power Supply needs to make more then 350 watts and it won't allow that so it shuts off.

Thanks guys ~ everyone's help is much appreciated

Chrissicom · Post by **Chrissicom** » Sat Jul 29, 2006 7:50 am

The Cheetas require about 1A in idle which is quite a lot for a hard drive but normal for SCSI. 7A minimum alone by hard disks (there is a lot of other 12V stuff in your system) drives an Antec Phantom 350 insanely hot. I had the same PSU once in a case with 1 120mm underneath and two 80mm fans above the Antec Phantom and it was still getting too hot if I installed it above the mainboard. When I installed the PSU below the mainboard heat was just before shutdown and my power requirements were far below your system.
It might be that your PSU is close to shutdown temp and as soon as the optical drives kick in as well the load gets too high and there's too much wattage or too much temp generated.

marvin-miller · Post by **marvin-miller** » Sat Aug 05, 2006 11:30 pm

Hi Chrissicom;

I replaced the Phantom 350 with a 500 and it's been running for days now without an issue. I'd have to say the 350 did not have enough juice to do the trick.

Actually, I think the real issue is that the 350's strict policy of not letting more then exactly 350 watts to be drawn from the PS is what did it. That's the only reason I can see for my cheap (but good) 320 watt unit being able to power the system. Because it didn't have that protection circuitry it kept making power? Something like that...