Uncreative Labs

Joined: 05 Oct 2007 Posts: 24 Location: Catalunya

Hi i am planning about taking profit of some junk...

40, 60,80 and 200GB IDE hard disks (SeeGates)
One old very tall tower box (6 5.25 bays)

A clunker AT psu (working) but needs a new fan.

I seen on ebay some IDE to USB adapters, i plan to power the disks with the psu, connect them with a usb hub and case it together in the ATX box. (Like a Gov. spec USB hard disk)

My doubt, as the rattiest individual in the planet, is if one IDE to USB adapter can work with 2 drives (as master / slave) Also i need to know how many hard disks i can connect to a 280W AT PSU.

(consider the whole invention works w/out a MoBo)

Joined: 20 Nov 2004 Posts: 589 Location: Shandong, China

You should be able to calculate the maximum power consumed by your drives by taking the multiplying the current by the voltage for both the 12V ad 5V lines and adding them together. I have a 7200RPM barracuda infront of me here, and it lists the following on the top cover:

12V, 0.54A
5V, 0.46A

(12 * 0.54 + 5V * 0.46) = 8.7VA (W)

I would guess most 3.5" IDE drives typically consume between 10 to 15W at 7200rpm. If you're running 15,000rpm SCSI it could be a lot higher. Anyway, my drive does not specify whether or not the power rating is typical or peak. The external enclosure it is contained is has a 100W external power brick, so I assume there must be a reason for it being so much higher.

You will also have to consider the power being drawn from the CPU, GPU, RAM, system board and other expansion cards, so your power needs could vary greatly.

In short, I've never ran that many drives before so I can't really answer your question. I think you should first figure out a rough figure for the total power consumption of your system and then ask around. Generally when designing electronics it is good to select parts capable of handling twice what is needed. I am not sure if this applies to power supplies as well. Harddrives tend to put a lot more stress on the power supply than other devices when going from the power on to steady state.

You should be aware that not all power supplies are created equally. Sometimes the RMS power is advertised, and sometimes the peak power is advertised. You will want to use the RMS ratings. Sometimes the RMS ratings are overstated as well, it's best to get one that is rated conservatively. If you are going to be putting a big load on a power supply and you want it to be reliable and last a long time it is best not to cheap out too much.

Does your full tower case look anything like this?

http://picasaweb.google.com/misterzeropage/MyVintageComputerStuff/photo#5204484585200514354

Joined: 05 Oct 2007 Posts: 24 Location: Catalunya

Hi, i got a bunch of barracudas too, the total Wattage would be less than 50W (put 70w to play safe ...), i am assembling the thing without any motherboard then i got enought power. I supose 280w, even RMS, can cope with this. I dunno how much power use the IDE to USB adapters i planned to use, but i bet for less than 5W all together.

Nope, my case was made in 2000, is a lot less sexier Confused

(a boring whiteish front plus a boring red button plus two boring LED'S)

Joined: 20 Nov 2004 Posts: 589 Location: Shandong, China

Yours may be sexier, but mine has a green lamp in the power switch Razz

It isn't quite visible because I used a flash to take this photo, but it looks pretty neat.

The big problem with mine is the missing panel cover. I'm still trying to figure out how to build a replacement.

Joined: 05 Oct 2007 Posts: 24 Location: Catalunya

No, no, i mean yours is a lot nicer, mine is pretty dull.

(now i regret trashing my old 486 case) With rocker power switch, green led mhz panel, and very aged yellowish plastic. THAT was a pinnacle of case design. Shocked

Joined: 20 Nov 2004 Posts: 589 Location: Shandong, China

I really don't know how I completely misread your comment. I must have been tired or something.

You should have kept the old yellow case and repainted it. If you do some reading you can actually do a near factory job. The nice part about the paint is that is doesn't go yellow. I believe IBM and Gateway 2000 painted black plastic on their old systems rather than using beige plastic...that is why they retain their complexion so well.

What's interesting is how over time the beige PC casings slowly became whiter. I was looking at my original 486 from 1992 which hasn't yellowed. It almost looks brown compared to my new Inwins. I really don't like when I buy a CD-ROM drive and the faceplate is bright white. Because of this I've switched over to black. I find it's easier to get the black components to match.