Need a replacement power supply with -5VDC

[Almighty1]

I am in need of a replacement power supply with -5VDC which seems to be needed for the ASUS P4C400-E motherboard as mentioned by others on the internet, anyone know a good way to find one as I have tried Best Buy and they all do not have the -5VDC. Thanks!

[brethin]

Re: Need a replacement power supply with -5VDC

I am in need of a replacement power supply with -5VDC which seems to be needed for the ASUS P4C400-E motherboard as mentioned by others on the internet, anyone know a good way to find one as I have tried Best Buy and they all do not have the -5VDC. Thanks!

Never heard of a Asus P4C400-E, did you mean Asus P4C800-E?

As for the power supply, I have several that would work for you (has the -5vdc). I would be willing to sell you one just send me a PM (private message) on your price range and I will send you a list.

[c_hegge]

Re: Need a replacement power supply with -5VDC

That board (P4C800-E) does not have ISA slots, so no, you do not need -5V. Any PSU will be fine.

EDIT: I probably could add that it would probably be best NOT to use a PSU with a -5V rail, simply because those that do have it usually have most of the current available on the +5V rail, while that board has the CPU powered by the +12V rail. Power supplies that have a decent amount of current on the +12V rail, rarely have a -5V rail.

[Almighty1]

Re: Need a replacement power supply with -5VDC

Yes, I meant ASUS P4C800-E Deluxe, forgot to double check before I posted.

The P4C800-E may not have ISA slots but it requires a PSU with -5V as this has been mentioned by others who tried to use a PSU without -5VDC and the system just wouldn't even post.

http://www.c-amie.co.uk/technical/ps...010-intel-478/

[c_hegge]

Re: Need a replacement power supply with -5VDC

Well, OK. I'll be darned. No other motherboard in the world without ISA slots requires a -5V rail. ( to ASUS for that one).

[etnietering]

Re: Need a replacement power supply with -5VDC

It might be easier to just add your own -5v rail to a power supply you already have.

Something like the MC34063 could be used to take some of that excess +5v and invert it to -5v. Only takes a handful of extra parts, and the datasheet has all the equations you need to figure out all the component values.

Alternatively, if the board just needs -5v present to POST, and not for anything else, you could take a PSU with a -12v rail (which is still most, I believe) and use a 7905 to linear regulate that down (or up?) to -5v. Not as efficient, nor as "fun" in a EE sense, but cheaper and easier than the 34063 by far.

[Almighty1]

Re: Need a replacement power supply with -5VDC

I guess what I can also do is just buy a modern Power supply from a store that has a good return policy and try it and see what happens. Maybe that guy just bought a bad Power Supply or something. My question is, if the PSU comes with a 24 pin connector, will it still work fit the 20 pin mobo connector without using an adapter? Also, any brands and models out there that make PSUs at the same level as PC Power & Cooling Turbo-Cool or better? I see Corsair, EVGA, and Thermal Take at Best Buy but not sure which is good.

[Almighty1]

Re: Need a replacement power supply with -5VDC

I had tried a Corsair CX750m Power Supply which does not have a -5VDC rail and it appears to work fine for everything except the on-board Intel Pro1000/CT 1Gbps NIC is not working as it has two orange lights, I read someone said Wake-On LAN needs -5VDC to work properly so could this be the reason why it needs the -5VDC rail? At least ASUS shows the -5vdc in the manual:
http://www.manualslib.com/manual/579...page=42#manual

Not sure if that is why the NIC is not working as it says device fails to start properly in Windows XP SP3.

etnietering, thanks for the info. I just realized the 2000/2001 PC Power & Cooling Turbo-Cool 450ATX power supply that failed last week does have a Motorola MC7905CT in it.

[japlytic]

Re: Need a replacement power supply with -5VDC

How about a 7905 negative regulator with its input connected to the -12V rail?

[Almighty1]

Re: Need a replacement power supply with -5VDC

japlytic, that was basically what etnietering mentioned earlier but how exactly do you find the -12v rail and is there a tutorial somewhere showing how to do the connection for the circuit illiterate?

[budm]

Re: Need a replacement power supply with -5VDC

So the Corsair CX750m has -12V output (0.8A)
http://www.corsair.com/en-us/cx-seri...ed-modular-psu
LM79xx series, see PDF for how to use it.
Do you know how much the current requirement for the -5V will be?

[Almighty1]

Re: Need a replacement power supply with -5VDC

Thanks budm as always! Am I correct that I only need to hook up to the input leg and then basically have the output going to where the white wire is on the ATX Motherboard power connector? The -5V should be no more than 0.3A as thats what my PC Power & Cooling Turbo-Cool 450-ATX outputs according to the specs on the PSU casing so that number should be able to handle everything.

[Behemot]

Re: Need a replacement power supply with -5VDC

The -12 V rail has blue wire on the ATX connector. I also suggest some capacitor for the regulator output, something like 100 uF is more than enough. The regulator usually has pretty smooth output enough but just to be sure…

[budm]

Re: Need a replacement power supply with -5VDC

You need to install small caps at both input and output so it will not oscillate, see the notes in the spec sheet.

[Behemot]

Re: Need a replacement power supply with -5VDC

There is a cap on the other side of the blue wire, in the PSU, so I think that one will be enough…

[budm]

Re: Need a replacement power supply with -5VDC

Good design will have the caps installed as close to the IC, I always have the caps installed in my designs. That -12V feeding wire will be longer than 3 inch.

[Almighty1]

Re: Need a replacement power supply with -5VDC

Seems like the Rubycon ZLH or 16v 100uF caps would work. I noticed the spec sheet says 25uF, wouldn't 100uF be too much though?

[Tic]

Re: Need a replacement power supply with -5VDC

Hi guys i upload the thread to speak about power supply to these motherboard.

The needing of -5v line,In this notherboard is a urban legend i don't know why this thing was expanded years ago along with pci cards 2.3 incompatibilidad But there are in the begining and belive It to

I Have now a technisat power supply with no -5v line with it. The power supply is a crap power supply, But i can't change It. Because in reality the motherboard have a problem with the today psu standards

The problem is the motherboard need alot of A in 3.3v 5v and 5v line. Because all their logic work with it, except cpu fans, hdds cd rom etc..

Today modern psu can have 80 Plus certificación. High Japan codensers modular etc.. But at final the problem is they have very low power in the 3.3v and 5v line combines power. 110w 130w 150w. This kill the motherboard. And make It reset continusly or so. The cheap crappy chinese power supplies are made with cheap obsolete especificación. Deliverig more power in the old rails.that because cheap power supply works

I search and search powers supply with more power in 3.3v and 5v. But i not have very Lucky.

If they have 250w usually the have two 12v rails with is connected probably with pci-e 6 pin so you lost these raíl. As probably they akasa es600w 550 450. Maybe is possible buy and adapter pci-e 6 pin atx 4+4 pins and use these rail for cpu But i not try it. I only view It in eBay from a eeuu seller.

Other as tacen mars gaming 700w.(200w). Have poor elements inside.

Spire or lcpower ave very low wattage in the 12 raíl. Un fortunly.

If anyone know a good power supply(good quality) can work with the board please tell me, my technimax works, But the voltage are little outside of 5℅ in 3.3v 5v line some times.

[cpt.charlie]

Re: Need a replacement power supply with -5VDC

Any decent PSU from 2002-2006 will do the job, these units had strong 3.3/5v rails and about 14-18A on 12V line.

[Tic]

Re: Need a replacement power supply with -5VDC

But a 2006 psu second hand..


I found maybe and option, But i not know if it is crap or something decent :

http://www.coolmod.com/kloner-k750go...category_id=12

http://kloner.es/fuentes-atxsfxtfx/3...n-de-750w.html