Power supply for very old motherboard

[pastel tundra]

Hi !
lately I’ve been playing with some old computers. I have found an ASUS A7V8X-X motherboard for socket A (socket 462) without a single failed cap, and I want to use that poor thing a bit with windows XP
the thing is : the actual psu (a unknown brand 480 watt with 4 molex and a 20+4 atx) work, but smell absolutely horrible when in use. I’m pretty sure a psu is not supposed to smell bad, and I don’t want to open it to check the capacitor. so i want to change it for a textorm TX650+ (but any other psu can work, I just want lot of molex)
can this power supply work ? I checked the info of the manufacturer of the board, and I found some image about psu need. I have no clue if modern standard atx psu can work with it, I don’t want to kill the board

So in summary :
Can a modern PSU work on a 22 years old motherboard

I have some image of the documents I found and a pic of the psu

Thanks for the help !

Also the computer work, I started it and everything is fine (except for the smell) I stoped it as soon as I smelled it. The smell is hard to describe, it’s not like a normal burning thing, it more like burning chemical maybe ?

Maybe if I let the psu working outside for a bit the smell will stop, but I don’t feel good using that

[vernal depot]

From a glance feels like any normal atx power supply will work, may just have to be careful about the dimensions, so it fits, but wait for some other responses, I am not sure if I am missing something.

@livid yacht when you are available, could you take a look here.

[pastel tundra]

The weird thing is the pin layout seems to be reversed on the chematic. It’s calling it atx pwm and after atx12v

No clue who did that. Idk if (but I don’t think) this one is a high quality board, I have another from a year before with twice the port on it, but the chipset is locked to agp 4x. The gpu i will use (GeForce 6800) seems to be agp x8

[gray lintel]

the plug and its countpart are always reversed to each other because you look always at the plugging side - not the "cable side" - on it.
Somewhere the specs/manual should tell which ATX Version is needed. Does the board need 3,3V ?

[pastel tundra]

Oh yeah that’s true. How I didn’t think of that XD

[pastel tundra]

I didn’t check for the 3,3v

[gray lintel]

Is it this model?
https://www.amazon.fr/Alimentation-HEDEN-PSX-A830-V2-2-HE04XC/dp/B00NA4GRJG?language=en_GB&currency=EUR

[pastel tundra]

It seems

Mine doesn’t have sata tho

[gray lintel]

The power supply specs changed over time in the way the power between 12V, 5V and 3.3V is balanced...
You can't expect that the current generation of power supplys works with very old mainboards! 🙁 matching 20 pin plugs is not enough.
i can't give a definitive answer, maybe this one: old supplys have old capacitors inside and these are surely dry and to replace the stinky supply with another old supply gets stinkier....

[pastel tundra]

Well no modern psu then, I wonder if the smell will finally get away. Is it dangerous to use it ? Through the psu vent I didn’t saw blown/fat capacitor

It’s just extremely dusty

[gray lintel]

It could also have "release valve" and/or leaked electrolytes and dust on top, so you couldn't see it.

[pastel tundra]

Possible yeah

Not sure it’s a good idea to open it

[gray lintel]

Well, i wouldn't exclude all modern psu. i guess a modern 900 W and above psu is less susceptible than a modern 500 W psu - but i don't know exactly!

[pastel tundra]

Could a not 100% compatible psu kill the mainboard ?

[gray lintel]

i can't exclude it. how much do you want to risk? financially? do you need/want/like the mainboard that dearly?

[pastel tundra]

It’s a fun project, and I have a rescue one (one year prior, worse agp, kt333 instead of kt400 so no usb2 and agp 8x). I can definitely risk it. I can put a random GeForce mx400 and don’t really damage anything valuable

[gray lintel]

so, for fun sakes... 😄

[pastel tundra]

I will still wait for other people answer, but maybe I can try something. I also have some random old psu but they come from the same place. Not sure for the reliability

It was all given for free

So no financial loss

Also gave me a pentium 1 and a i486 2dx (but no motherboard for them sadly)

[gray lintel]

😆 something like that is also in my garage 🤭
need to go now, it's half past eleven in the night (local time). bye* 🥱

[pastel tundra]

Bye ! Thx for the help

[pastel tundra]

So, I did some digging
From what I understand, some old motherboard need a -5v pin, but that pin got removed when ISA disappeared. This motherboard 20 pin layout doesn’t seem to need one. So modern psu with a -12 and no -5 should work

But there is something else, older psu have way more amps in the 3,3v and 5v than the 12v. So modern psu, even if the pins are correct doesn’t guarantee good operation.

I found this psu with 22 amps on both 3,3 and 5 volt. But the max amount it can throw is 120w Is that sufficient ?

The full system is :
asus A7V8X-X motherboard
one ide hdd, one ide cd reader
nvidia GeForce 6800 (with one molex connector)
sound blaster audigy sx platinium pro (with one molex too)

[livid yacht]

The old 20pin is technically still compatible with modern PSUs if they have a split 20+4 connector, so you can just plug the 20pin part in. You correctly observed that older PSUs had more power delivery over 3.3V and 5V, but there are modern PSUs that should be able to deliver enough for this.
Bear in mind that this is an Athlon platform, definitely only 32bit, and likely maxing out at 1.5GB of RAM.

[livid yacht]

ATX specification prevents this in theory, but I am not sure anybody ever tried this in practice.

[pastel tundra]

Well the motherboard max at 3 gb, I use 2 rn (and won’t add more)

[livid yacht]

That is pretty good for that platform.

[pastel tundra]

Yeah I was lucky to get that one

No clue if it was high end or not, but it has a kt400 chipset

[livid yacht]

Be careful with GPUs, the AGP slot had different voltages for different generations: https://forums.tomshardware.com/threads/difference-between-1-5v-agp-and-3-3vagp.870830/

[pastel tundra]

Oh Alr thx for that info

The board is from 2003 and gpu from 2004

[livid yacht]

Should be AGP8x on both then. But do check that before putting it in.

[pastel tundra]

Both the board and gpu seems to be agp8x

I also have an older socket A with agp x4

[pastel tundra]

So you think this could work ? Even without the -5v ?

[livid yacht]

Depending on what you want to do, getting a simple PCI graphics card may be the easier option.

[livid yacht]

I think it should.

[pastel tundra]

Sadly I only have agp and pci on that board, and pci-e psu (except for a intel 740 and the geforce 6800)

[livid yacht]

Yes, and I meant PCI, not PCIe. I still have an old Voodoo3 PCI for such occasions.

[pastel tundra]

Oh i can write back, no clue what just happened

Got timed out for trying to correct a message

[pastel tundra]

Thx for the help

[livid yacht]

Do report how it went. If you want to put Linux on this, your choices are limited. I would probably try AntiX.

[pastel tundra]

I will try win xp on that machine

Never had to install an os on hardware this old. I do have a windows 98 installation cd and windows xp upgrade one

[livid yacht]

XP is compatible with this, 98 might be difficult because of the RAM (too much for 98).

[pastel tundra]

Oh yeah isn’t 98 maxed out at 512 mb ?

[livid yacht]

I don't remember. I think ME had trouble above 512MB, which suggests 98 would need to go even lower.

[pastel tundra]

I have 256 on my windows 98 se machine. Lucky for me the os was already installed when I got it

It’s a p2 350mhz and the gpu is integrated in the motherboard

[vernal depot]

Sorry, Discord being weird, "... card__s(ex__cept ..." triggered "sex" keyword for some reason
Should not affect you anymore and will find some fix if it happens again to another message.

your message edit.

Sadly I only have agp and pci on that board, and pci-e cards(except for a intel 740 and the geforce 6800)

[pastel tundra]

alr thx !

[pastel tundra]

Good news ! Modern psu work

For now with limited hardware, I will add the main gpu and soundcard after, I don’t want to brick them