Splicing New PSU to 18 Pin Motherboard

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Splicing New PSU to 18 Pin Motherboard

Postposted on Fri Jul 22, 2011 12:16 pm

Hey guys

Basically my All in One Sony Vaio Power Supply is Dying . It had become dangerous , making buzzing noises and I am afraid of it blowing or causing a fire . I spent about £20 calling SOny for a replacement, though they no longer make them , and have dug around for hours on end trying to find an identical replacement
I managed to get a 20 Pin PSU to fit in the case despite the Vaio's awkward size , however the Sony motherboard has an Odd 18 Pin connector.
So I cut off the MOBO 18 pin male connector off the faulty, original PSU and spliced it to my replacement PSU .I had heard of this method working beofre !
I noticed the old PSU had a brown wire connected to the motherboard which the new PSU doesn't have. THe old PSU also had an extra ground Ground wire for the Mobo. At the moment I have just taped up the brown and spare black wires from the cut off , old male connection plug. Because as the New PSU doesn't have a brown wire or a spare or enough spare black wire .
everything else is spliced to the replacement PSU , I press the on buton and nothing is happening .I also notice the inevitable spare red and blue wires on the replacement PSU

Any suggestions ?
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Re: Splicing New PSU to 18 Pin Motherboard

Postposted on Fri Jul 22, 2011 12:24 pm

Losing an extra ground is probably not a big deal. I'm more concerned with the mystery brown wire, and the fact that the other wires may not follow the standard PSU wiring color code (since the whole PC is obviously quite non-standard).
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Re: Splicing New PSU to 18 Pin Motherboard

Postposted on Fri Jul 22, 2011 12:40 pm

Upon further research/reflection...

Assuming the color codes match ATX spec, here's what I'd recommend:

- Splice the extra ground together with one of the other grounds.

- The brown wire should be a 3.3V sense wire, which the PSU uses to sense (and compensate for) resistive losses in the wiring harness. Did one of the pins of the new PSU's original connector have two orange wires (one thick, one thin) running into it? If so, the thin orange one is likely the one you need to connect the brown wire to.

If they used a non-standard color code, you're going to need to figure out what the proprietary code is... and unfortunately, depending on how they've mangled it, you may have already damaged the motherboard and/or PSU.
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Re: Splicing New PSU to 18 Pin Motherboard

Postposted on Sun Jul 24, 2011 3:30 am

Hi

All the orange wire's were on a separate pin ,below are pictures for more information . Still cant get her to turn on , still wondering :( what the problem could be

1st picture here's a picture of the splicing , it seems every other wire matches up
]Image






2 Here's the old PSU]Image




3 Here's the new PSUImage


4 Here's everything wired up Image
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Re: Splicing New PSU to 18 Pin Motherboard

Postposted on Sun Jul 24, 2011 8:05 am

That Advance power supply has less than half the capacity of your original unit. I wouldn't expect it to hold up for long.
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Re: Splicing New PSU to 18 Pin Motherboard

Postposted on Sun Jul 24, 2011 8:19 am

I plugged the machine into a watt/power meter with the old PSU and it only ever uses 150w to 180w under full load . How can you tell the Advance power supply has less than half of the capacity ? Could that be the reason it doesn't even switch on?
I thought it was a difference of 50 watts ( Advance PSU 250w - Delata PSU 295)
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Re: Splicing New PSU to 18 Pin Motherboard

Postposted on Sun Jul 24, 2011 8:24 am

CPUs and graphics cards draw most of their power from the +12V rail. The original Delta power supply has two +12V rails rated at 11 and 12 amperes each. If they both can work at their maximum at the same time (not a given), that would be (11 A + 12 A) x 12 V = 276 watts. The Advance PSU is rated at a near-useless 5 A of +12 V = 60 watts.
Last edited by JustAnEngineer on Sun Jul 24, 2011 8:27 am, edited 1 time in total.
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Re: Splicing New PSU to 18 Pin Motherboard

Postposted on Sun Jul 24, 2011 8:27 am

JustanEngineer , thanks , silly of me to think it might power it then? I am sending a PM
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Re: Splicing New PSU to 18 Pin Motherboard

Postposted on Sun Jul 24, 2011 8:52 am

A good quality 80+% efficient 300-watt PSU should be more than adequate, other than the pinouts not matching up. Something like the Enermax ENP350AGT NAXN or Corsair CMPSU-430CX for £35 would do the trick.

If you don't want to butcher the wiring on the new power supply, you could do your splicing to an ATX extension cable, letting you plug a standard 24 pin ATX connector into your harness.
http://www.scan.co.uk/products/akasa-ak ... 24f-pin%29
http://www.scan.co.uk/products/akasa-24 ... b24-24-ext
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Re: Splicing New PSU to 18 Pin Motherboard

Postposted on Sun Jul 24, 2011 9:35 am

Yup, total wattage is not the only thing that matters. Older systems drew more of their power from the +3.3V and/or +5V rail; modern systems draw nearly all of their power from the +12V rail. PSUs designed for older systems tend to have a more even distribution of capacity between the +3.3V/+5V rails and +12V rails, whereas newer ones put most of the capacity on +12V.

Looks like the Advance unit is a fairly old design...
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Re: Splicing New PSU to 18 Pin Motherboard

Postposted on Thu Jul 28, 2011 10:27 am

Ok
Thanks for your replies guys , I ordered a brand new TFX FSP 300 WAtt dual rail PSU , it came through the post this morning . I will let you know how it goes and will eventually make a video for people with the same 'common problem'
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Re: Splicing New PSU to 18 Pin Motherboard

Postposted on Mon Feb 10, 2014 2:30 pm

I really, really wish this guy had followed up.

Apologies for necro-posting.
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