Cutting and changing wires from Hp to generic PSU

[Readit-Later]

Hi, I am thinking about case swapping my HP G1 400 SFF to ATX size tower case with bigger PSU in order to run a proper GPU.. i know it usually it involves buying 24pin to 8 pin/6 pin converter etc which is hard to find (& is sometimes converter itself costs half the cost of these cheap pre-owned SFF pcs..) also these converters dont always work, like in my case i cant post to bios as my Hp G1 400 gives beep sounds when i use the conveter. Works fine on its own PSU. So I am thinking why not just replace the ATX PSU wires with HP wires by simply cut & connect? is it even possible? I have seen people just cut unnecessary wires and reconnect them for cable management.. but can we use the HP wires on a normal full size PSU? I have old 400watt PSU & willing to waste it for sake of experiment but just wanted some suggestions as I never done it before.

[Somerandomtechyboi]

12 minutes ago, Readit-Later said:

Hi, I am thinking about case swapping my HP G1 400 SFF to ATX size tower case with bigger PSU in order to run a proper GPU.. i know it usually it involves buying 24pin to 8 pin/6 pin converter etc which is hard to find (& is sometimes converter itself costs half the cost of these cheap pre-owned SFF pcs..) also these converters dont always work, like in my case i cant post to bios as my Hp G1 400 gives beep sounds when i use the conveter. Works fine on its own PSU. So I am thinking why not just replace the ATX PSU wires with HP wires by simply cut & connect? is it even possible? I have seen people just cut unnecessary wires and reconnect them for cable management.. but can we use the HP wires on a normal full size PSU? I have old 400watt PSU & willing to waste it for sake of experiment but just wanted some suggestions as I never done it before.

What you are doing is just splicing some cables to a connector thatd fit on the hp mobo, shouldnt be that hard with some basic soldering tools and a pinout for the power connector on the hp board

 

Absolutely possible as its just a bunch of wires arranged differently compared to the usual atx 24 pin, thats literally what those 24 pin adapters do

[jaslion]

You can buy a 15$ adapter or like ali express 5$ same thing. Which is a far better better idea. Yes they cost a lot respective to these old units but its best.

 

Any reason why you're spending money on such an old thing?

 

You can just buy the desktop sized one for like 50$ if you want a desktop sized one

 

You could cut and solder. But only do thatbif you are decent at doing it and use proper equipment. Probably wont be cheaper than a convertor

 

 

[manikyath]

i'm pretty sure the power supply in the 400G1 is HP's flavour of 12VO, meaning they dont have a +5vsb rail either, instead going for a +12vsb rail.

 

to convert to normal ATX you'll need at least a DC-DC converter to drive that +12vsb rail from the +5vsb rail.

[mariushm]

The reason you need adapter cables is because the motherboard expects 12v stand-by, but regular ATX power supplies produce 5v stand-by.

 

So on the adapter cable, there's a tiny dc-dc converter which boosts 5v stand-by to 12v so that the motherboard will detect and use this 12v and think it's a regular HP power supply.

 

Other than this dc-dc converter the adapter cable does just what you think, rearranging some 12v wires to go in the small connector going to motherboard. If there's a second connector, it's just for the power_ok , power_on, maybe -12v for serial ports and maybe some optional wires (some hp models allow controlling power supply fan speed from the motherboard).

 

You could make your own  boost regulator (5v to 12v) using a cheap 1-2$ module from eBay, for example this : https://www.ebay.com/itm/382508609599

or you could find a MC33063 / MC34063 chip and the components it needs (inductor, capacitors, resistors) to configure it in boost (step-up) mode and boost 5v stand-by to 12v = these 33063/34063 are like pennies and can be found in cheap usb car chargers and other things.

[Somerandomtechyboi]

1 hour ago, jaslion said:

You could cut and solder. But only do thatbif you are decent at doing it and use proper equipment. Probably wont be cheaper than a convertor

Itll be cheaper if you already have the soldering tools, may or may not be if you dont

 

Though i guess it is kind of a pain having to cut and splice a buncha wires together

 

2 minutes ago, mariushm said:

The reason you need adapter cables is because the motherboard expects 12v stand-by, but regular ATX power supplies produce 5v stand-by.

So thats what those little box looking things on adapters are for

 

Good to know not like ill actually bother with a crappy oem board atleast anything post lga 775 cause no fsb + voltmodding oc shenanigans so no fun =p

[Readit-Later]

alright.. so it's lot more complex than I thought!

I have tried a cheap adaptor via AliExpress but it didn't work as the seller claimed it works for multiple hp sffs but i guess not. The white P2 plug (power check) has different color cables then the HP ones. 

 

I took this 30$ HP 400g1 SFF as a project and don't wana spend 22$ just for an adaptor (no thanks Amazon Australia)..

 

@mariushm thanks mate for enlightening us, will definitely try to find the dc-dc conveter for 5v to 12v issue. 

 

my first post so thanks again for prompt responses.