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Dual PSU's

N

neo86

Gawd
Joined
Aug 19, 2001
Messages
560
After I got an extra 512 MB of RAM I noticed my system would freeze right after detecting my drives. I have four: Two 40 GB 7200 RPM, one 36 GB 15,000 RPM SCSI drive, and an NEC3520A. I had no clue what the problem was so I did the usual jumper stuff on the drives, and then I thought it might be a power issue. I unplugged one of my hard drives and everything worked fine. So... I searched online to figure how to use one of my old 250 watt PSU's to run some other drives/fans. I used a paper clip to start it up, and since I don't really turn off my computer...ever it's not too big of an issue for me to have to turn it on automatically.

Question is: Has anyone tried this? Is it really that bad to run it without a motherboard? It's really perfectly right now...
 
I've done it before, but only with an AT powersupply. It actually worked fine, but looked ghetto as hell. I think the fact that I had both powersupplies duct taped to the top of my case helped with the ghetto part a little though.
 
I did that for almost six months with an AT psu. HDDs are great when it comes to that.
 
a rudimentary tutorial for ATX dual PSUs



cut and paste 101
----------------------------------------------------------------------------------------------------------
synch 2 PSU each as a seperate bus

1. Hardwired (what a CMStacker's adapter does)
2. With a relay

or employing a shared bus Like a redundant PSU

1. with resistors
2. with mosfets
3. with diodes (Single Source Fault Tolerant Power Systems)

(3 is slightly outdated now see gee's post > http://hardforum.com/showthread.php?t=776885)

I ran 2 hardwired 400 watts and a large RAID array for 3 years without issue on one of my boards (Abit KR7A)
however it may have been a contributing factor in the death of another board (ECS whatever :p )
though Im not at all sure about that

not running them synchd however certainly corrupted the hell out of the array :p
eventually switched to a Zippy Emacs MR3-6450P N+1
with considerably less total wattage but plenty for what was actually required
with 32A on the +12V rail for the drives and considering the mobo's VRM was powered off the +5V
---------------------------------------------------------------------------------------------------------------------------------

for hardwired thats

between the 2 PSUs its
green to green (POW_ON \ power on)
black to black (COM \ ground)

and on just the second PSU
grey to black (Power Good to COM\Ground)

but consider your being massively ineffcient and pumping out alot more heat
when what it sounds like is you have a junk PSU and simply need one good one.
 
My current PSU is an Antec 480 watt TruePower. Is that a junk PSU? Just a question for future reference really. I don't want to buy Antec again if I'm going to have this problem again. :D I was under the impression Antec was pretty good.
 
no but then it might not have been designed to power your current config either
its entirely possible that most of its capacity is unused (+3.3V & +5V rails) while the +12V rail is extremely overtaxed

which is why watts dont mean Jack

why dont you list your full config (including all fans ect)
and the model designation of that Antec
 
neo86 said:
My current PSU is an Antec 480 watt TruePower. Is that a junk PSU? Just a question for future reference really. I don't want to buy Antec again if I'm going to have this problem again. :D I was under the impression Antec was pretty good.
Click to expand...
Antec makes very good PSU's, but the old TP 480W's only had +12V@22A, the new ones are +12V@28A &
the newest True Power II 480W have +12V1@18A & +12V2@18A, although the max combined is more like +12V@32A.

Today's systems power the CPU from the +12V rail, older computers from the +5V rail.

Good Luck,
Dave
 
davidhammock200 said:
Today's systems power the CPU from the +12V rail, older computers from the +5V rail.
Click to expand...

and PCI-E is pure +12V horsepower
as is most supplemental power to AGP cards

so what has in effect occurred is that on a modern rig the GPU & CPU have joined all the drives, fans and the mobo itself at the +12V teat :p
 
So in my next PSU it would be best to get one with dual 12V rails? :confused:

My current setup:

Abit AN7 (nForce2)
Athlon XP 2400+ Mobile @2000 MHz
2x512 MB Corsair/Kingston PC3200 (@PC3200)
Radeon 9800SE
Adaptec 29160N SCSI Controller
Hauppauge WinTV+RADIO PCI
NetGear FA310TX NIC (My router took out my onboard NIC during a storm :( )
Maxtor 40GB 7,200RPM 2 MB Cache
Western Digital 40GB 7,200 RPM 8 MB Cache
IBM 36 GB 15,000 RPM 8 MB Cache
2x120 mm fans around the radiator
2x80 mm fans near the back
1x80 mm fan for the drive cage with the SCSI drive in it

Haha... Now that I list it like that I can see why my PSU might have trouble... Though my setup isn't exactly up-to-update in terms of computer aging. :D
 
neo86 said:
So in my next PSU it would be best to get one with dual 12V rails? :confused:

My current setup:

Abit AN7 (nForce2)
Athlon XP 2400+ Mobile @2000 MHz
2x512 MB Corsair/Kingston PC3200 (@PC3200)
Radeon 9800SE
Adaptec 29160N SCSI Controller
Hauppauge WinTV+RADIO PCI
NetGear FA310TX NIC (My router took out my onboard NIC during a storm :( )
Maxtor 40GB 7,200RPM 2 MB Cache
Western Digital 40GB 7,200 RPM 8 MB Cache
IBM 36 GB 15,000 RPM 8 MB Cache
2x120 mm fans around the radiator
2x80 mm fans near the back
1x80 mm fan for the drive cage with the SCSI drive in it

Haha... Now that I list it like that I can see why my PSU might have trouble... Though my setup isn't exactly up-to-update in terms of computer aging. :D
Click to expand...
The number of rails is not the issue, the +12V amperage is the issue.
Both the PC P&C 510SLI & OCZ PowerStream 520W are single +12V rail & they are IMO the BEST of class.
nVidia "strongly recommends" +12V@26A for non-SLI & +12V@34A for SLI.

Dave ;)
 
Haha... Yeah, I got that it's the amperage... I just figured that saying "dual 12V rails" implied more amperage though after looking at NewEgg I can see that's no necessarily the case. I am looking at a power supply which has a dual 12V rails and has a total amperage of 34 for those. I doubt I will get one any time soon. I'm a poor college student. It's just good to know what to get :p

I'm really not sure which rails use the most amps in my system. :eek: There are some PSU's out there with like... 50 A on the 3.3V and 25 A on the 12 V. I suppose if I need a combined amperage of 34 A on dual 12V to run an SLI setup it should be more than enough for my computer. ;)
 
neo86 said:
Haha... Yeah, I got that it's the amperage... I just figured that saying "dual 12V rails" implied more amperage though after looking at NewEgg I can see that's no necessarily the case. I am looking at a power supply which has a dual 12V rails and has a total amperage of 34 for those. I doubt I will get one any time soon. I'm a poor college student. It's just good to know what to get :p

I'm really not sure which rails use the most amps in my system. :eek: There are some PSU's out there with like... 50 A on the 3.3V and 25 A on the 12 V. I suppose if I need a combined amperage of 34 A on dual 12V to run an SLI setup it should be more than enough for my computer. ;)
Click to expand...
What mobo & CPU?
 
neo86 said:
Abit AN7 (nForce2)
Athlon XP 2400+ Mobile @2000 MHz
Click to expand...

I posted above my full system specs, but here's the part you requested... Hehe.
 
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